JP5264380B2 - Structural analysis method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structural analysis method which enables accurate calculation in a short time with regard to the structural analysis of a member injection-molded using a material containing a filamentary material. <P>SOLUTION: The structural analysis method for the member to be injection-molded using the material containing the slender filamentary material includes a shape acquisition step of obtaining shape information indicating the shape of the member, an element division step (S2) in which the entire shape of the member is divided into a plurality of elements to produce element information indicating each divided element, a thermal analysis step (S3) in which thermal characteristic values indicating the thermal characteristics of the member by carrying out thermal analysis by the use of each element indicated by the element information on the assumption that a heat source is in a part corresponding to the gate of a mold for charging the material to produce thermal characteristic information including it, a conversion step (S4) for converting the thermal characteristic information into physical property information indicating physical property values for carrying out the structural analysis, and a structural analysis step (S5) for carrying out the structural analysis of the member using the physical property information and information indicating each element. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a structure analysis method and a property value calculation method for structure analysis, and more particularly to a structure analysis method of an injection molded product using a fiber reinforced resin material.

  The injection-molded resin member is used for various daily members such as a television, an air conditioner, a cellular phone casing, and a car bumper. As the use of resin members expands, the performance and properties required for resins are becoming higher. For example, a thin and strong material is required to meet the demand for reducing the weight of mobile phones. As described above, a fiber reinforced resin obtained by adding a fiber such as glass or carbon to a resin is often used for a member that requires durability and impact resistance in order to improve rigidity and strength.

  In order to verify the members and the strength of the members, a structural analysis using a finite element method or the like is performed. Since numerical simulation can verify the performance of various members at a relatively low cost, it contributes to cost reduction and reliability improvement of the members. Structural analysis is also generally performed for resin members, and structural analysis in consideration of fiber orientation has been proposed particularly for fiber reinforced resins (see, for example, Patent Document 1 and Patent Document 2). In the fiber reinforced resin, the former is about 3 to 5 times stronger than the latter in the strength in the fiber direction and the strength in the direction perpendicular to the fiber. Therefore, structural analysis in consideration of fiber orientation is an important technique for improving the accuracy of strength prediction of the fiber reinforced resin to be injection-molded.

  Specifically, the structural analysis described in Patent Document 1 includes roughly three steps. First, the flow analysis of the resin flowing through the mold is performed using the elements for flow analysis. Here, the fiber orientation information indicating the fiber orientation of each element is acquired by setting the flow direction of each element as the fiber orientation of each element.

  Next, the fiber orientation information acquired in the flow analysis step is converted into fiber orientation information for structural analysis. The mesh used for analysis differs between the flow analysis and the structural analysis. For example, a flow analysis uses a fine mesh of millions of elements to accurately simulate fiber behavior, whereas a structural analysis uses a coarse mesh of hundreds of thousands of elements. Therefore, by converting the fiber orientation information associated with the element for flow analysis into the fiber orientation information associated with the element for structural analysis, the physical property value considering the fiber orientation can be used for the structural analysis.

Finally, a structural analysis is performed using structural analysis elements and structural orientation fiber orientation information. In the structural analysis, physical property values considering fiber orientation are used based on fiber orientation information. Thereby, highly accurate structural analysis becomes possible.
JP 2006-272928 A JP 2004-25796 A

  However, in the conventional structural analysis considering the fiber orientation, there is a problem that it takes a lot of time to calculate the entire structural analysis.

  That is, first, the flow analysis takes a lot of time. This is because the calculation time increases as the mesh becomes finer in the analysis, and in the flow analysis, the calculation is performed using a relatively fine mesh as described above. Moreover, it takes time to convert the fiber orientation information for flow analysis into the fiber orientation information for structural analysis. Since the mesh used for analysis differs between flow analysis and structural analysis, this conversion associates the elements for flow analysis with the elements for structural analysis, and then fiber orientation to match each corresponding element Information needs to be converted from one for flow analysis to one for structural analysis. As described above, the number of elements for flow analysis is about several million elements and the number of elements for structural analysis is about hundreds of thousands of elements, so the time required for this calculation is long.

  The present invention solves the above-mentioned problems, and calculates the structural analysis of a member injection-molded using a material containing a fibrous substance in a shorter time while maintaining or improving the accuracy of the conventional structural analysis. A structural analysis method, a structural analysis device, a structural analysis program, a physical property value calculation method for structural analysis, a physical property value calculation device for structural analysis, and a physical property value calculation program for structural analysis are provided.

In order to solve the above-mentioned problem, the structural analysis method according to the present invention is:
A structure analysis method for a member that is injection-molded using a material containing a fibrous substance,
A shape acquisition step of acquiring shape information of the member;
An element dividing step of dividing the member into a plurality of elements and generating element information indicating each divided element;
Using each element indicated by the element information, a thermal characteristic value indicating the thermal characteristic of the member is calculated by performing a thermal analysis assuming that there is a heat source in a portion corresponding to the gate of the mold into which the material is poured, and calculating A thermal analysis step for generating thermal characteristic information including the thermal characteristic value,
A conversion step of acquiring the thermal characteristic information and converting the acquired thermal characteristic information into physical property information including physical property values used for structural analysis;
It looks including the structural analysis step of performing a structural analysis of the member by using the above physical property values included in the property information, and the respective elements which the element information indicating,
In the thermal analysis step, the thermal characteristic information including the heat flux vector information indicating the heat flux vector of each element is generated,
In the conversion step,
Obtaining the thermal characteristic information including the heat flux vector;
Converting the heat flux vector into physical property information including physical property values in consideration of the orientation of the fibrous material by setting the orientation of the fibrous material as the heat flux vector .

  In the present invention, the structural analysis of a member injection-molded using a material containing a fibrous substance can be calculated in a shorter time while maintaining or improving the accuracy of the conventional structural analysis.

  Embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows the appearance of a structural analysis apparatus according to Embodiment 1 of the present invention. The structural analysis device 20a is a device that performs structural analysis of a member that is injection-molded using a material containing an elongated fibrous substance, and is, for example, a computer that can execute a software program. A display unit 22 such as a liquid crystal display, an input unit 24 such as a keyboard and a mouse, a CAD (Computer-aided design, see FIG. 2) device, and the like are connected to the structure analysis apparatus 20a. In the present embodiment, a description will be given using a fan as an example of a member that performs structural analysis. The display unit 22 in FIG. 1 shows a state where the fan is divided into elements as will be described later.

  The member may be made of a resin containing a fibrous substance, and includes products, semi-finished products, parts, and the like. As specific examples, in addition to the above fans, automobile bumpers and TV outer frames Body, mobile phone casing, and the like.

  FIG. 2 is a block diagram of the structural analysis apparatus 20a according to the first embodiment. As shown in the figure, the structural analysis apparatus 20a includes an input information acquisition unit 52 that acquires information input by a user from the input unit 24, and a plurality of storage units realized by a storage medium such as a hard disk. As will be described in detail later, each storage unit holds information generated by each processing unit, information acquired by the input information acquisition unit 52 based on user input, and the like in a predetermined format.

  The element storage unit 32 stores element information 32a that is information for specifying the positional relationship of each element divided for analysis. FIG. 3 shows a specific example of the element information 32a according to the first embodiment. The element information 32a includes an “element number” for specifying each element and information indicating the position of each element. In the present embodiment, each element is a tetrahedron including four vertices from “vertex 1” to “vertex 4”. Therefore, the information indicating the position of each element holds information indicating the coordinates of each vertex in the coordinate system fixed to the member. In the present embodiment, each element is an example of a tetrahedron, but the shape of each element is not limited to a tetrahedron, and a rectangular parallelepiped or the like may be appropriately selected according to the shape of the member.

  The thermal analysis condition storage unit 34 stores thermal analysis condition information 34a that is information indicating conditions necessary for performing thermal analysis, such as information indicating boundary conditions for thermal analysis and information indicating the position of the heat source. Yes. The thermal analysis condition information 34 a is information stored by the user via the input information acquisition unit 52. FIG. 4 shows a specific example of the thermal analysis condition information 34a according to the first embodiment. The thermal analysis condition information 34a includes thermal conductivity, specific heat, gate temperature, node temperature, gate position, and the like for use in thermal analysis. In the present invention, since the thermal analysis is performed in order to obtain the thermal characteristics of the member, the thermal conductivity and the specific heat do not need to be accurate values of the material of the member, and may be any value, for example, 1. The gate temperature is the temperature of the portion corresponding to the gate of the mold into which resin is poured for injection molding, and the node temperature is the temperature of the node where the boundaries of the elements intersect. These temperatures are also arbitrary values set as appropriate. FIG. 4 shows an example in which the gate temperature is 1 and the node temperature is 0. The gate position indicates the position of the part corresponding to the gate of the mold.

  The thermal characteristic storage unit 36 stores thermal characteristic information 36a and 36b indicating thermal characteristic values calculated by thermal analysis performed by the structural analysis device 20a. The thermal characteristic information 36a, 36b of the present embodiment includes heat flux vector information 36a and temperature information 36b. FIG. 5 shows a specific example of the heat flux vector information 36a according to the first embodiment. The heat flux vector information 36a is information representing the heat flux vector of each element calculated by thermal analysis. FIG. 6 shows a specific example of the temperature information 36b according to the first embodiment. The temperature information 36b is information representing the temperature of each element calculated by thermal analysis.

The conversion condition storage unit 38 stores conversion condition information 38a that is information for converting the thermal characteristic value calculated by the thermal analysis into a physical property value used for the structural analysis of the member. The conversion condition information 38 a is information stored by the user via the input information acquisition unit 52. FIG. 7 shows a specific example of the conversion condition information 38a according to the first embodiment. The conversion condition information 38a includes conditions for converting a thermal characteristic value into a physical property value that takes orientation into consideration, as shown in FIG. Specifically, the conversion condition information 38a indicates the local maximum value and minimum value in the member for each of the elastic modulus E _{MD in} the fiber direction, the elastic modulus E _{TD in the} direction perpendicular to the fiber direction, and the density ρ. Contains information to indicate. In the conversion condition information 38a, for example, the maximum elastic modulus E _MDmax in the fiber direction is _set to 140000 (kg / cm ² ).

  The physical property storage unit 40 stores physical property information 40a which is information indicating the physical property value of each element used for the structural analysis. FIG. 8 shows a specific example of the physical property information 40a according to the first embodiment. The physical property information 40a includes the physical property value of each element obtained by converting the thermal characteristic value of each element. The elements for which the thermal characteristic value and the physical property value are calculated are the same, and both are associated by an element number in the present embodiment.

  The structure analysis condition storage unit 42 stores structure analysis condition information 42a that is information indicating conditions for performing structure analysis. The structural analysis condition information 42 a is stored by the user via the input information acquisition unit 52. Although details of the structure analysis condition information 42a are not shown, for example, boundary conditions used for the structure analysis are included.

  The structural analysis result storage unit 44 stores structural analysis result information 44a that is information indicating the result calculated by the structural analysis. FIG. 9 shows a specific example of the structural analysis result information 44a according to the first embodiment. The structural analysis result information 44a includes information indicating the stress and displacement of each element as a result of the structural analysis. The elements here are the same as the elements from which the above-described thermal characteristic values and characteristic values based thereon are calculated, and these are associated by element numbers.

  Referring to FIG. 2 again, the structural analysis device 20a further includes a shape acquisition unit 56, an element division unit 58, a thermal analysis unit 60a, a conversion unit 64a, a structural analysis unit 66, and a display control unit 70. . An instruction given to each processing unit by the user is delivered via the input information acquisition unit 52.

  The shape acquisition unit 56 acquires shape information indicating the shape of the member. The shape acquisition unit 56 of the present embodiment acquires shape information from the CAD device 26 through a connection line.

  When obtaining the shape information from the shape obtaining unit 56, the element dividing unit 58 divides the entire member into a plurality of elements, thereby generating element information 32a.

  The thermal analysis unit 60a acquires the thermal analysis condition information 34a from the thermal analysis condition storage unit 34, acquires information indicating each element of the member from the element division unit 58, and performs thermal analysis based on the acquired information. . In addition, the thermal analysis unit 60 a stores thermal characteristic information 36 a and 36 b including an analysis result obtained by thermal analysis in the thermal characteristic storage unit 36.

  When the thermal analysis process by the thermal analysis unit 60a is completed, the conversion unit 64a acquires the conversion condition information 38a from the conversion condition storage unit 38, acquires the thermal characteristic information 36a and 36b from the thermal characteristic storage unit 36, and acquires these. Based on the obtained information, the thermal characteristic value is converted into a physical property value of the member.

  FIG. 10 is a block diagram illustrating details of the conversion unit 64a according to the first embodiment. As illustrated, the conversion unit 64 a includes a thermal characteristic information acquisition unit 72 a, a conversion condition information acquisition unit 78, and a physical property value calculation unit 80.

  The thermal characteristic information acquisition unit 72a is a processing unit that acquires the thermal characteristic information 34a from the thermal characteristic storage unit 34, and acquires the thermal flux vector acquisition unit 74a that acquires the thermal flux vector information 36a and the temperature information acquisition that acquires the temperature information 36b. Part 74b. The conversion condition information acquisition unit 78 acquires the conversion condition information 38 a from the conversion condition storage unit 38. The physical property value calculation unit 80 calculates the physical property value of each element based on the heat flux vector information 36a, the temperature information 36b, and the conversion condition information 38a. The physical property value calculation unit 80 stores the physical property information 40a including the physical property value obtained by the conversion in the physical property storage unit 40, and notifies the structure analysis unit 66 that the conversion process has been completed.

  When the conversion processing by the conversion unit 64a is completed, the structure analysis unit 66 acquires the element information 32a from the element storage unit 32, acquires the physical property information 40a from the physical property storage unit 40, and acquires the structural analysis condition from the structural analysis condition storage unit 42. Information 42a is acquired, and structural analysis is performed based on the acquired information. The structure analysis unit 66 causes the structure analysis result storage unit 44 to store the structure analysis result information 44a including the analysis result obtained by the structure analysis. Further, the structure analysis unit 66 delivers the structure analysis result information 44 a to the display processing unit 70.

  The display processing unit 70 displays the result of the structural analysis on the display unit 22 based on the structural analysis result information 44a.

  Next, details of processing executed by the structural analysis apparatus 20a according to Embodiment 1 will be described with reference to a flowchart.

  FIG. 11 is a flowchart of processing executed by the structural analysis apparatus 20a according to the first embodiment. The shape acquisition unit 56 acquires shape information from the CAD device 26 via a communication line (S1). The element dividing unit 58 divides the entire member into a plurality of elements without duplication based on the shape information, thereby generating element information 32a, and storing the generated element information 32a in the element storage unit 32 (S2). ). An example in which the fan 90a as a member is divided into elements is shown in FIG.

  The thermal analysis unit 60a performs a thermal analysis process (S3). FIG. 13 is a flowchart showing details of the thermal analysis process (S3). The thermal analysis unit 60a acquires the element information 32a from the element division unit 58 (S11). The thermal analysis unit 60a acquires the thermal analysis condition information 34a from the thermal analysis condition storage unit 34 (S12). The thermal analysis unit 60a uses the information acquired in each acquisition process (S11 and S12), for example, performs a thermal analysis by a finite element method, and thereby calculates a thermal characteristic value including the heat flux vector and temperature of each element. (S13). Here, the finite element method is one of the numerical analysis methods used for thermal analysis and structural analysis to be described later. The object is divided into a plurality of small elements, and simplified equations are combined into each element. It is a technique to apply and numerically obtain a solution that satisfies the applied equation. Since the finite element method is a well-known technique, a detailed description thereof will be omitted.

  The thermal analysis unit 60a stores thermal characteristic value information (heat flux vector information 36a, temperature information 36b) including the thermal characteristic value calculated in the thermal characteristic value calculation process (S13) and stores it in the thermal characteristic storage unit 36. (S14).

・・・式（１） Here, the governing equation of heat conduction used for the thermal analysis by the thermal analysis unit 60a is shown in Formula (1).

... Formula (1)

In Equation (1), Κ is the thermal conductivity, T is the temperature, q (with three dots on top) q is the internal heating value per unit volume, ρ is the density, c is the specific heat, t is the time, V _x , V _y , V _z represent the heat velocities in the conductive medium, respectively.

・・・式（２） On the other hand, the governing equation used for the flow analysis is shown in Equation (2).

... Formula (2)

In the formula (2), V _x , V _y , and V _z represent the flow velocity of the resin, P represents the pressure, and τ represents the surface force.

・・・式（３） The first to fifth terms on the right side of Equation (2) represent thermal conduction, internal energy due to compression, work due to normal stress, work due to shear stress, and internal heat generation, respectively. Moreover, in injection molding CAE (Computer Aided Engineering), Formula (2) can be simplified like Formula (3) on the assumption of (a)-(g) shown below.
(A) The fluidized rice cake is thin. That is, the flow length is sufficiently longer than the wall thickness, so that the flow component V _{z in the} wall thickness direction can be ignored.
(B) Since the resin is a highly viscous fluid, the inertial term and the bulk force term are small compared with the surface force and can be ignored.
(C) The velocity gradient in the plane direction is sufficiently smaller than the velocity gradient in the thickness direction, so that the in-plane surface force can be ignored.
(D) Since the model shape is thin, the thermal conductivity in the plane direction is sufficiently smaller than the thermal conductivity in the thickness direction. Therefore, the thermal conductivity in the plane direction can be ignored.
(E) The internal energy due to compression is negligible because the velocity gradient is small.
(F) The work due to the normal stress is considered as internal heat generation only at the rapidly changing section.
(G) Work due to shear stress is intended only for the velocity gradient component in the thickness direction.

... Formula (3)

  The right side of Equation (3) is simplified to terms of heat conduction, work due to shear stress of the velocity gradient component in the thickness direction, and internal heat generation terms. When this is compared with the equation (1), the governing equation of heat conduction is a simplified governing equation of flow analysis that ignores the influence of shear stress of the velocity gradient component in the thickness direction. Therefore, when the shear stress can be ignored, that is, when the viscosity and the shear rate that determine the shear stress can be ignored, the flow analysis can be simply approximated by the heat transfer analysis. Here, since the viscosity is expressed as a function of shear rate, temperature, and pressure, when the member has a simple shape in which these do not change greatly, the orientation of the fibrous substance contained in the material, That is, it is useful to use the governing equation of heat conduction in order to analyze the direction of the fibers poured into the mold.

  Specific examples of the shape in which the shear rate, temperature, and pressure do not change greatly include a shape with a small number of gates and a shape with little increase / decrease in plate thickness. In addition, the flow transition part (flow tip, inside of the molded product far from the mold, etc.) is also a part where the shear rate, temperature and pressure do not change greatly. Can be obtained. In this case, the heat flux vector is a value indicating the orientation of the fiber.

  Thus, the orientation of the resin contained in the member is obtained by performing thermal analysis. As can be seen from the complexity of the governing equation expressed by Equation (2), the calculation of the flow analysis is complicated and takes a lot of calculation time. On the other hand, the calculation load of the thermal analysis is lighter than that of the flow analysis, so that it is possible to shorten the time required for calculating the orientation of the resin.

  FIG. 14 shows a part of the heat flux vector of each element obtained by the thermal analysis of the fan 90a. The direction and length of each arrow shown in FIG. 14 indicate the direction and magnitude of the heat flux vector of each element, respectively. When resin is poured into the gate portion 92a where the mold gate is located at the time of molding, the resin spreads radially from the gate portion 92a to the far side of the blade, and it is shown that it flows along the contour of the blade. Yes. Since the direction of the fiber contained in the resin is along the flow direction of the resin, the arrow in FIG. 14 indicates the orientation of the fiber.

  FIG. 15 is a photograph showing the front of the fan 90a, and FIG. 16 shows an enlarged image of the rectangular portion 94b shown in FIG. 15 by an X-ray CT (Computed Tomography) apparatus, and the rectangular portion of FIG. 94a corresponding to 94a. In the image shown in FIG. 16, a black linear substance is a fiber contained in a resin. As can be seen from FIG. 16, the fibers are generally directed from the upper right to the lower left.

  FIG. 17 is a diagram showing the fiber orientation of the fan 90a created based on the image obtained by the X-ray CT apparatus. Compared with the whole of FIG. 14, the fiber orientation obtained by the thermal analysis, that is, the direction of the arrow shown in FIG. 14 and the orientation of the actual fiber based on the image by the X-ray CT apparatus substantially coincide. I understand that. Therefore, the orientation of fibers contained in the resin can be accurately simulated by thermal analysis.

  Refer to FIG. 11 again. The conversion unit 64 converts the thermal characteristic value obtained by the thermal analysis into a physical property value used for the structural analysis (S4). FIG. 18 is a flowchart showing details of the conversion process (S4) of the first embodiment.

  The thermal characteristic information acquisition unit 72a acquires thermal characteristic information 36a and 36b (S21). More specifically, the heat flux vector acquisition unit 74a acquires the heat flux vector information 36a, and the temperature information acquisition unit 74b acquires the temperature information 36b. The conversion condition information acquisition unit 78 acquires the conversion condition information 38a from the conversion condition storage unit 38 (S22). The physical property value calculation unit 80 calculates a physical property value based on the heat flux vector information 36a, the temperature information 36b, and the conversion condition information 38a (S23).

  Here, the physical property value calculation process (S23) by the physical property value calculation unit 80 will be described in detail.

・・・式（４） First, the physical property value calculation unit 80 converts the temperature of each element into the elastic modulus of each element. In this conversion, the following equation (4) is used. In Equation (4), the temperature of the element to be converted is T, the maximum temperature and the minimum temperature are T _max and T _min , the elastic modulus in the fiber direction of the element is E _MD , and the maximum elastic modulus and the minimum elastic modulus in the fiber direction. _Are E _MDmax and E _MDmin , respectively.

... Formula (4)

Incidentally, modulus _{E TD} of fibers perpendicular direction, the _{E MD} of formula (4) _{E TD,} the _{E mdmax} to _{E TDmax,} converted by the respective substituting equation of _{E mdmin} to _{E Tdmin.}

As described above, the physical property value calculation unit 80 associates the maximum temperature included in the temperature information 36b with the maximum value (for example, E _MDmax ) of the elastic modulus included in the conversion condition information 38a, and the minimum temperature included in the temperature information 36b. _{Is associated} with the minimum value (for example, E _MDmin ) of the elastic modulus included in the conversion condition information 38a, and the temperature is set such that the higher the temperature included in the temperature information 36b, the greater the elastic modulus of the element. The temperature of each element included in the information 36b is associated with the elastic modulus of each element on a one-to-one basis. In this embodiment, when the temperature of each element is obtained by weighting each of the maximum temperature and the minimum temperature, the maximum value of the elastic modulus and the minimum value of the elastic modulus are A value obtained by weighting the same as when the temperature is obtained is calculated as the elastic modulus of each element.

  In general, in one member, the elastic modulus is large near the gate, and the elastic modulus decreases as the distance from the gate increases. The difference in the elastic modulus of the resin containing the fiber is mainly caused by the difference in the length of the fiber contained in the resin. Specifically, the elastic modulus of the resin increases as the fiber length increases. When the resin is allowed to flow through the mold, many long fibers remain in the vicinity of the gate because they are difficult to flow. On the other hand, since the short fiber is easy to flow, it flows to a part away from the gate. For this reason, the elastic modulus tends to increase in the vicinity of the gate as described above and decrease as the distance from the gate increases.

  On the other hand, the temperature distribution of the member when the gate is used as a heat source is high in the vicinity of the gate and the temperature is lowered as the distance from the gate is increased, as in the ease of fiber flow. Therefore, the elastic modulus distribution caused by the difference in fiber fluidity and the temperature distribution as a result of heat transfer show similar tendencies. And the temperature and elastic modulus of each element are substantially matched by simple conversion like said Formula (4).

  Next, in the physical property value calculation process (S23), the physical property value calculation unit 80 calculates the orientation of the elastic modulus based on the heat flux vector of each element. A coefficient (matrix) for converting the entire coordinate system into an element coordinate system which is a coordinate system of each element is calculated so that the fiber direction of each element coincides with the direction of the heat flux vector. This coefficient (matrix) is a value (matrix) indicating the orientation of each element.

・・・式（５） Finally, the physical property value calculation unit 80 converts the temperature of each element into the density of each element. In this conversion, the following formula (5) is used. In Expression (5), the temperature of the element is T, the maximum temperature and the minimum temperature included in the temperature information 36b are T _max and T _min , the element density is ρ, and the maximum density and the minimum density of the conversion condition information 38a are ρ, respectively. Let _max and ρ _min .

... Formula (5)

As described above, the physical property value calculating unit 80 associates the maximum temperature included in the temperature information 36b with the maximum density ρ _max included in the conversion condition information 38a, and sets the minimum temperature included in the temperature information 36b as the conversion condition information 38a. The temperature of each element included in the temperature information 36b is set to correspond to the minimum value ρ _{min of the} density included in the temperature information 36b so that the higher the temperature included in the temperature information 36b, the higher the density of the element is. One-to-one correspondence with the elastic modulus of the element. In the present embodiment, when the temperature of each element is obtained by weighting each of the maximum temperature and the minimum temperature, the temperature of each element is set to the maximum value of the density and the minimum value of the density. A value obtained by weighting the same as that obtained is calculated as the elastic modulus of each element.

  In general, in the case of a member having a simple shape such as a plate having a uniform thickness, the resin is less likely to flow as the distance from the gate of the mold increases. This is because the temperature of the resin is high near the gate of the mold, but the temperature of the resin decreases as the distance from the gate increases, and the viscosity of the resin increases accordingly. Since the viscosity of the resin flowing through such a mold changes, the density of the member increases at the gate portion and decreases as the gate portion is separated. Therefore, the density distribution of the member is the same as the temperature distribution of the member when the gate portion is used as a heat source. And the temperature and density of each element are substantially matched by simple conversion like said Formula (5).

  Returning to the description of the conversion process of FIG. 18, finally, the physical property value calculation unit 80 stores the physical property information 40a indicating the calculated physical property value in the physical property storage unit 40 (S24). The physical property values here include the elastic value, orientation, density, etc. in the fiber direction and the direction perpendicular to the fiber direction as described above (FIG. 8 shows the fiber direction for the element having the element number “1000” and the direction perpendicular thereto. The elasticity value of a direction and a density are illustrated.) The elastic value in the fiber direction and the direction perpendicular to the fiber direction, and the value indicating the orientation are collectively referred to as an orientation elastic value hereinafter.

  In this way, the conversion process does not consider the difference between the divided elements, that is, does not perform mapping of elements caused by different divided elements, integration or distribution of values of the respective elements, and the like. As will be described later, in the present invention, the same division element can be used in the thermal analysis and the structural analysis. Therefore, the conversion process can be simplified and the processing time can be shortened.

  Refer to FIG. 11 again. The structural analysis unit 66 performs structural analysis of the member using the physical property values calculated in the conversion process (S4) (S5). FIG. 19 is a flowchart showing details of the structure analysis process (S5).

  The structure analysis unit 66 acquires the element information 32a from the element storage unit 32 (S31). The element information 32a acquired here is element information generated by the element dividing unit 58 in the element dividing process (S2). That is, it is the same as the element information used for the thermal analysis process (S3).

  The structure analysis unit 66 acquires the physical property information 40a from the physical property storage unit 40 (S32). The physical property information 40a acquired here is the physical property value calculated in the conversion process (S4), that is, in the present embodiment, includes the orientation elastic value and the density.

  The structure analysis unit 66 acquires the structure analysis condition information 42a from the structure analysis condition storage unit 42 (S33). The structural analysis condition information 42a is information including conditions such as boundary conditions necessary for the structural analysis. Specifically, each of the divided elements or the nodes of each element, for example, displacement and rotation constraints, loads, stresses, etc. It is information including conditions that are set as appropriate by the user according to the situation where the analysis conditions are assumed.

  In the case of the fan 90a, the structural analysis condition information 42a includes, for example, information in which a portion that fits into a rotation shaft inserted in the center of the fan 90a is a fixed end and another surface is a free end. Further, the structure analysis condition information 42a in this case may include information indicating the centrifugal force according to the rotational speed and the air pressure received by the fan.

  Similar to the thermal analysis process (S3), the structural analysis unit 66 performs structural analysis by using a method such as a finite element method using the elements included in the element information 32a. Thereby, the structure analysis unit 66 calculates the structure analysis result, and generates the structure analysis result information 44a including the calculated structure analysis result (S34). In the present embodiment, the structural analysis result includes the stress and displacement of the member. Based on the result of the structural analysis, for example, the thickness of the blades of the fan 90 that can withstand the maximum rotational speed can be examined based on the structural analysis in consideration of the orientation of the fibers. Therefore,

  Thus, the same division element is used in the structural analysis and the thermal analysis. Therefore, it is not necessary to convert the physical property value of each element calculated based on the mapping between different elements, that is, the result of the thermal analysis, into different elements. Therefore, the structural analysis process can be simplified, and the calculation time required for the process can be shortened. The structural analysis uses physical property information in consideration of fiber orientation. Therefore, highly accurate structural analysis becomes possible, and a dense and advanced design of a member and a mold for injection molding becomes possible.

  Returning to the description of the structure analysis processing of FIG. 19, finally, the structure analysis unit 66 stores the structure analysis result information 44a in the structure analysis result storage unit 44 (S35). Thereby, the user holds the result of the structural analysis and can refer to it as needed.

  Returning again to FIG. The display control unit 70 acquires the structural analysis result information 44 a from the structural analysis unit 66 and displays an image indicating the structural analysis result information 44 a on the display unit 22. Thereby, the structural analysis apparatus 20a ends the process.

  As described above, the calculation load can be reduced in the calculation process of the fiber characteristic information and the process of converting the fiber characteristic information into the physical property information. Therefore, the processing time required for each process is shortened. Moreover, since the structural analysis is performed based on the physical property information in consideration of the fiber orientation, a highly accurate structural analysis result can be obtained. Therefore, it is possible to perform a highly accurate structural analysis in a shorter time than the case of calculating by a conventional technique.

(Embodiment 2)
In the second embodiment, the structural characteristic value is calculated by converting the thermal characteristic value calculated by the thermal analysis. Here, the structural characteristic value is a value indicating the structural characteristics of the member, and in this embodiment, is the strength of each element of the member.

  In the second embodiment, the strength is calculated in consideration of the position where the weld occurs (weld position) in the member where the weld occurs.

  The weld is a portion where the flow of the material poured into the mold merges and is fused, and often appears in a linear shape or a belt shape, but the shape is not limited thereto. The weld is generated at a position where the material flowing from each gate collides when the material is poured from a plurality of gates. Further, for example, when a window or a hole is provided in the member, the weld is generated in the vicinity thereof. The weld impairs the appearance of the member, and the strength decreases at the weld position. Therefore, the weld may cause a failure of the member.

  In order to prevent defects due to welds, various contrivances are made to the molding die and member. For example, a mold gate is provided and the shape of the mold and the member is designed so that a weld is generated at a position having little influence on the strength of the member. Further, the temperature of the material to be poured is adjusted so that the generation of welds can be suppressed. As described above, in a member in which a weld is generated, it is important to predict a weld position as a premise for preventing defects due to the weld.

  Embodiment 2 of the present invention will be described below with reference to the drawings. In the present embodiment, the same reference numerals are assigned to the same parts and processing units as those in the first embodiment throughout the drawings.

  FIG. 20 shows the appearance of the structural analysis apparatus according to the second embodiment of the present invention. The structural analysis device 20b is a device that calculates the strength of a member that is injection-molded using a material containing an elongated fibrous substance. In the present embodiment, the plate 90b displayed on the display unit 22 shown in FIG. 20 will be described as an example of a member. As shown, the plate 90b has two gate portions 92b and 92c corresponding to the gates of the mold. Since the member has a plurality of gate portions, a weld is generated in the plate 90b.

  FIG. 21 is a block diagram of the structural analysis apparatus 20b according to the second embodiment. Hereinafter, a storage unit that stores information characteristic of the present embodiment and a processing unit that performs processing characteristic of the present embodiment will be described, and a memory that stores information similar to that of the first embodiment The description here regarding the processing unit and the processing unit that performs processing is omitted.

  The element storage unit 32 stores element information 32b as in the first embodiment. The element information 32b includes, as shown in FIG. 22, the size of each element in the x direction, y direction, and z direction, and the reference position of each element associated with the “element number” for specifying each element. Including. Since each element of the present embodiment is a cube as shown in the display unit 22 of FIG. 21, the positional relationship of each element can be specified by the element information 32b. In the present embodiment, the size in the x direction (Δx), the size in the y direction (Δy), and the size in the z direction (Δz) are all “0.5”, and the element number is “1”, for example. The reference position of the element is “(0, 0, 0)”. Although this element is used for calculation such as thermal analysis as in the first embodiment, a tetrahedron, a cube, or the like may be selectively used as the shape of the element.

  The thermal analysis condition storage unit 34 stores thermal analysis condition information 34b. Unlike the thermal analysis condition information 34a according to the first embodiment, the thermal analysis condition information 34b according to the present embodiment includes two gate positions, as shown in FIG.

  The thermal characteristic storage unit 36 stores thermal characteristic information 36c to 36e. 24 to 26 show specific examples of temperature gradient information 36c, heat flux vector information 36d, and temperature information 36e, respectively, of the thermal characteristic information. The temperature gradient information 36c includes information indicating a temperature gradient in each element. The heat flux vector information 36d and the temperature information 36e are information indicating the heat flux vector and temperature of each element, as in the first embodiment.

The conversion condition storage unit 38 stores conversion condition information 38b. The conversion condition information 38 b is information stored by the user via the input information acquisition unit 52. FIG. 27 shows a specific example of the conversion condition information 38b according to the second embodiment. The conversion condition information 38b includes a condition for converting the thermal characteristic value into intensity, as shown in FIG. As the strength, the lesser of the tensile strength, the yield point strength, 70% of the tensile strength or the yield point strength may be used. The strength of the resin containing fibers is greatly different between the direction of the fibers and the direction perpendicular thereto. Therefore, the strength of the resin containing fibers has orientation. Hereinafter, the strength in the direction along the fiber is σ _MD , and the strength in the direction perpendicular to the fiber is σ _TD .

Specifically, the conversion condition information 38b is used to obtain the maximum strength of the member in order to obtain the strength of each element (strength σ _{MD in the} fiber direction and strength σ _{TD in the} direction perpendicular to the fiber direction). Information indicating a value and a minimum value (maximum intensity σ _MDmax , minimum intensity σ _MDmin ) is included. The conversion condition information 38b shown in FIG. 27 shows an example in which the maximum strength σ _MDmax in the fiber direction is 1800 (kg / cm ² ). The conversion condition information 38b also includes a weld strength magnification that is a coefficient for calculating the strength at the weld position.

  The weld strength magnification indicates the strength at the weld portion relative to the strength of the material itself, that is, how much the strength of the portion where the weld is generated in the material is higher than the strength of the material itself. The conversion condition information 38b shown in FIG. 27 shows an example in which the weld strength magnification is 1/3.

  Refer to FIG. 21 again. The thermal analysis unit 60b according to the present embodiment acquires the thermal analysis condition information 34b from the thermal analysis condition storage unit 34, acquires information indicating each element of the member from the element division unit 58, and based on the acquired information. Thus, thermal characteristic information 36c to 36e including temperature gradient information 36c, heat flux vector information 36d, and temperature information 36e is calculated.

  When the thermal analysis process by the thermal analysis unit 60b is completed, the conversion unit 64b acquires the conversion condition information 38b from the conversion condition storage unit 38, acquires the thermal characteristic information 36c to 36e from the thermal characteristic storage unit 36, and acquires these. Based on the obtained information, the thermal characteristic value is converted into intensity.

  FIG. 28 is a block diagram illustrating details of the conversion unit 64b according to the second embodiment. As shown in the figure, the conversion unit 64b includes a thermal characteristic information acquisition unit 72b, a conversion condition information acquisition unit 78, a weld position specification unit 82, and an intensity calculation unit 84a.

  The thermal characteristic information acquisition unit 72b includes a thermal flux vector information acquisition unit 74a that acquires the thermal flux vector information 36d from the thermal characteristic storage unit 36, a temperature information acquisition unit 74b that acquires the temperature information 36e from the thermal characteristic storage unit 36, A temperature gradient information acquisition unit 74c that acquires temperature gradient information 36c from the thermal characteristic storage unit 36; The conversion condition information acquisition unit 78 acquires the conversion condition information 38b from the conversion condition storage unit 38 as in the first embodiment.

  The weld position specifying unit 82 acquires the temperature gradient information 74c via the temperature gradient information acquisition unit 74c, and specifies the weld position of the member based on the acquired temperature gradient information 74c. FIG. 29 is a diagram showing a temperature distribution calculated by thermal analysis using two gate portions as heat sources. Referring to FIG. 29, the weld position 100 in the member 90b is a place where the flow of material such as resin flowing in from the gates 92b and 92c is merged. It is a place where the temperature is equal between the elements to be operated. Therefore, the element whose temperature gradient is equal to or less than the threshold is specified as the weld position 100.

  The weld position specifying unit 82 generates information indicating the element of the specified weld position as weld position information, and delivers the information to the strength calculation unit 84a.

  Note that the threshold value of the temperature gradient for specifying the weld position may be “0”. In this case, an element having a temperature gradient of 0 is specified as a weld position.

  For example, temperature information may be used instead of the temperature gradient. For example, as can be seen from the isotherms 96a to 96e connecting the same temperatures in FIG. 29, the temperature of the material flowing into the mold from the gate gradually decreases as the distance from the gate portions 92b and 92c increases. Therefore, the weld position corresponds to a position where the temperature is low. Therefore, the weld position can be specified as a position having a temperature lower than the threshold value.

  The intensity calculation unit 84a acquires the conversion condition information 38b, the temperature information 36e, the heat flux vector information 36d, and the weld position information, and calculates the intensity based on the acquired information.

  Next, details of processing executed by the structural analysis apparatus 20b according to Embodiment 2 will be described with reference to a flowchart.

  FIG. 30 is a flowchart of processing executed by the structural analysis apparatus 20b according to the second embodiment. The shape acquisition unit 56 and the element division unit 58 are respectively similar to the shape information acquisition process (S1) and the element division process (S2) of the first embodiment, and the shape information acquisition process (S41) and the element division process (S42). Execute. An example of element division of the plate 90b according to the present embodiment is shown in FIG.

  The thermal analysis unit 60b performs a thermal analysis process (S43). FIG. 31 is a flowchart showing details of the thermal analysis process (S43) according to the second embodiment. The thermal analysis unit 60b acquires the element information 32b from the element division unit 58 (S51). The thermal analysis unit 60a acquires the thermal analysis condition information 34a from the thermal analysis condition storage unit 34 (S52). The thermal analysis unit 60a uses the information acquired in each acquisition process (S51 and S52), for example, performs a thermal analysis by a finite element method, and thereby, thermal characteristics including the heat flux vector, temperature gradient, and temperature of each element. A value is calculated (S53). The thermal analysis unit 60a stores the thermal characteristic information 36c to 36e including the thermal characteristic value calculated in the thermal characteristic value calculation process (S53) in the thermal characteristic storage unit 36 (S14).

  Referring to FIG. 30 again, conversion unit 64b converts the thermal characteristic value into intensity (S44). FIG. 32 is a flowchart showing details of the conversion process (S44) of the second embodiment.

  The thermal characteristic information acquisition unit 72b acquires thermal characteristic information 36c to 36e (S61). More specifically, the heat flux vector acquisition unit 74a acquires the heat flux vector information 36d, the temperature information acquisition unit 74b acquires the temperature information 36e, and the temperature gradient information acquisition unit 74c acquires the temperature gradient information 36c.

  The weld position specifying unit 82 specifies the weld position based on the temperature gradient information 36c (S62). Here, as described above, the weld position specifying unit 82 determines whether or not the temperature gradient of each element is equal to or less than a threshold value, and specifies an element that is equal to or less than the threshold value as a weld position.

  As described above, the weld position can be specified as a position where the temperature is lower than the threshold value. In this case, the weld position specifying unit 82 specifies the weld position from the temperature distribution (temperature of each element) instead of the process of specifying the weld position based on the temperature gradient information 36c (S62). That is, the weld position specifying unit 82 refers to the temperature information 36e including the temperature of each element, specifies the minimum temperature in the plate 90b, and the temperature of each element is equal to or less than the minimum temperature. Whether the element is equal to the minimum temperature or equal to or less than the threshold is specified as the weld position. Here, the minimum temperature in the plate 90b refers to the lowest temperature among the temperatures of the elements included in the plate 90b.

  The conversion condition information acquisition unit 78 acquires the conversion condition information 38b from the conversion condition storage unit 38 (S63). The intensity calculator 84a calculates the intensity based on the heat flux vector information 36a, the temperature information 36b, and the conversion condition information 38a (S64).

  Here, the intensity calculation process (S64) by the intensity calculator 84a will be described in detail.

  The strength calculation unit 84a converts the temperature of each element into the strength of each element. Here, the strength includes the magnitude of strength in the fiber direction, the magnitude of strength in the direction perpendicular to the fiber, and a value indicating the orientation of strength according to the fiber direction.

・・・式（６） In the intensity calculation process (S64), the following formula (6) is used to calculate the magnitude of each direction of the intensity. Equation (6) is obtained by replacing the elastic value E of Equation (4) with the strength σ, the element temperature is T, the maximum temperature and the minimum temperature are T _max and T _min , respectively, and the strength in the fiber direction of the element is The magnitudes of σ _MD and the maximum and minimum strengths in the fiber direction are σ _MDmax and σ _MDmin , respectively.

... Formula (6)

The elastic modulus sigma _TD fibers perpendicular direction, the sigma _MD of formula (6) to the sigma _TD, the sigma _mdmax the sigma _TDmax, converts the expression obtained by replacing each sigma _mdmin the sigma _Tdmin.

As described above, the strength calculating unit 84a associates the maximum temperature included in the temperature information 36b with the maximum strength (for example, the maximum strength σ _{MDmax in the} fiber direction) included in the conversion condition information 38b, and the minimum temperature included in the temperature information 36b. The temperature is associated with the minimum strength (for example, the minimum strength σ _{MDmin in} the fiber direction) included in the conversion condition information 38a, and the higher the temperature included in the temperature information 36b, the greater the strength of the element. The temperature of each element included in the temperature information 36b is associated with the intensity of each element on a one-to-one basis. In the present embodiment, when the strength of each element is obtained by weighting each of the maximum temperature and the minimum temperature, the temperature of each element is obtained for the maximum strength and the minimum strength, and A value obtained by applying the same weight is calculated as the intensity of each element.

  As described above, the vicinity of the gate in one member contains many fibers having a long length, and therefore the strength of the resin is high. And as the distance from the gate increases, the length of the contained fibers decreases, and therefore the strength decreases. Further, the temperature distribution of the member when the gate is used as a heat source is higher in the vicinity of the gate and lower as the distance from the gate is increased. Therefore, the distribution of the strength of the resin caused by the difference in the fluidity of the fibers and the temperature distribution as a result of the heat transfer have a similar tendency, and a simple equation such as the above formula (6) can be obtained. Almost matched by conversion.

  Next, in the intensity calculation process (S64), the intensity calculator 84a calculates the orientation of the intensity based on the heat flux vector of each element. A coefficient (matrix) for converting the entire coordinate system into an element coordinate system which is a coordinate system of each element is calculated so that the fiber direction of each element coincides with the direction of the heat flux vector. This coefficient (matrix) is a value (matrix) indicating the orientation of the strength of each element.

  The strength calculation unit 84a calculates the strength of the weld position (S65). The strength calculation unit 84a sets the magnitudes of the fiber direction calculated in the strength calculation processing (S64) and the strength in the direction perpendicular thereto for the element corresponding to the weld position specified in the weld position specifying processing (S62). By multiplying the weld strength magnification, the magnitude of the strength in each direction of the element corresponding to the weld position is corrected.

  The intensity calculation unit 84a includes the intensity corrected in the weld position intensity calculation process (S65) for the element corresponding to the weld position, and the intensity calculated in the intensity calculation process (S64) for the other elements. Is stored in the structure analysis result storage unit 44 as structure analysis result information 44b (S66).

  As described above, the strength of the member is directly calculated from the temperature distribution by converting the temperature distribution obtained by the thermal analysis. Moreover, the conversion is processed according to a simple expression such as the above expression (6), and therefore the processing time required for the conversion is short. Therefore, it is possible to perform the strength of the member with sufficient accuracy and in a very short time.

(Embodiment 3)
In the present embodiment, the stress distribution is calculated by the same method as in the first embodiment, the intensity distribution is calculated by the same method as in the second embodiment, and these calculated stress distribution and intensity distribution are used together. To create a safety factor distribution.

  Embodiment 3 of the present invention will be described below with reference to the drawings. In the present embodiment, the same reference numerals are assigned to the same parts and processing units as those in the first and second embodiments throughout the drawings.

  The external appearance of the structural analysis apparatus 20c according to the third embodiment is the same as the external appearance of the structural analysis apparatus 20a according to the first embodiment shown in FIG. 1. The structural analysis apparatus 20c according to the third embodiment includes, for example, a computer and This is realized by a display unit 22 such as a monitor and an input unit 24 such as a keyboard and a mouse connected thereto.

  FIG. 33 is a block diagram of a structural analysis apparatus 20c according to Embodiment 3 of the present invention.

As shown in FIG. 34, the conversion condition storage unit 38 stores conversion condition information 38c including conditions for calculating the elastic modulus E, the density ρ, and the strength σ. As the conversion conditions for calculating the elastic modulus E, the conversion condition information 38c includes the maximum elastic modulus E _{MDmax and} E _TDmax and the minimum elastic modulus E _{MDmin and} E _TDmin in the fiber direction and the direction perpendicular thereto. As the conversion condition for calculating the density ρ, the conversion condition information 38c includes a maximum density ρ _max and a minimum density ρ _min . As the conversion conditions for calculating the strength σ, the conversion condition information 38c includes the maximum elastic modulus σ _MDmax, σ _TDmax and the minimum elastic modulus σ _MDmin, σ _TDmin in the fiber direction and the direction perpendicular thereto.

  The structural analysis result storage unit 44 stores structural analysis result information 44c including information indicating the stress of each element as a result of the structural analysis and information indicating the strength of each element. In the present embodiment, the intensity not considering the weld position will be described as an example. However, the intensity considering the weld position is calculated in the same manner as in the second embodiment, and thereby the intensity considering the weld position is calculated later. A safety factor to be calculated may be calculated. The structural analysis result information 44c may include information indicating displacement.

  Further, the structural analysis result storage unit 44 stores structural analysis result information 44c further including information indicating the safety factor of each element calculated using the stress and the strength.

  When the thermal analysis process by the thermal analysis unit 60a is completed, the conversion unit 64c acquires the conversion condition information 38a from the conversion condition storage unit 38, acquires the thermal characteristic information 36a and 36b from the thermal characteristic storage unit 36, and acquires these. Based on the obtained information, the thermal characteristic value is converted into a physical property value and strength.

  FIG. 35 is a block diagram illustrating details of the conversion unit 64c according to the third embodiment. As illustrated, the conversion unit 64c includes an intensity calculation unit 84b in addition to the processing units included in the conversion unit 64a according to the first embodiment.

  The intensity calculation unit 84b acquires the heat flux vector information and the temperature information from the thermal characteristic information acquisition unit 72a, acquires information on the intensity σ of the conversion condition information from the conversion condition information acquisition unit 78, and based on the acquired information The strength of each element of the member is calculated.

  Reference is again made to FIG. The safety factor calculation unit 86 acquires the strength of each element calculated by the conversion unit 64a and the stress of each element calculated by the structural analysis unit from the structural analysis unit 66, and acquires the strength of each acquired element and the strength of each element. Using the stress, the magnification of strength with respect to the stress of the corresponding element (strength / stress) is calculated for each element.

  Next, processing executed by the structural analysis apparatus 20c according to the third embodiment will be described. FIG. 36 is a flowchart of processing executed by the structural analysis apparatus 20c according to the third embodiment.

  The shape acquisition unit 56 and the element division unit 58 are respectively similar to the shape information acquisition process (S1) and the element division process (S2) of the first embodiment, and the shape information acquisition process (S71) and the element division process (S72). Execute.

  The thermal analysis unit 60a performs the thermal analysis process (S73) in the same manner as the thermal analysis process (S3 in FIG. 11) of the first embodiment. The details of the thermal analysis process (S73) are the same as the details of the thermal analysis process of the first embodiment (see FIG. 13), so detailed description thereof is omitted here.

  The conversion unit 64c performs the same process as the thermal characteristic value-physical property value conversion process (S4 in FIG. 11) shown in detail in FIG. 18, thereby converting the thermal characteristic value into a physical property value (S74).

  Furthermore, the converter 64c converts the thermal characteristic value into intensity (S75). Details of the thermal characteristic value-intensity conversion process (S75) according to Embodiment 3 will be described with reference to the flowchart shown in FIG.

  The thermal characteristic information acquisition unit 72a acquires thermal characteristic information 36a and 36b (S81). More specifically, the heat flux vector acquisition unit 74a acquires the heat flux vector information 36a, and the temperature information acquisition unit 74b acquires the temperature information 36b.

  The conversion condition information acquisition unit 78 acquires the conversion condition information 38b from the conversion condition storage unit 38 (S82). The intensity calculator 84b calculates the intensity of each element based on the heat flux vector information 36a, the temperature information 36b, and the conversion condition information 38a (S83). The strength calculated here is the same as the strength calculated in the strength calculation process (S64) of the second embodiment, the strength in the fiber direction, the strength in the direction perpendicular to the fiber, and It includes a value indicating the orientation of strength according to the fiber direction. Subsequently, the strength calculating unit 84b stores the calculated strength of each element in the structural analysis result storage unit 44 as the structural analysis result information 44c (S84).

  Referring to FIG. 36 again, the structural analysis unit 66 performs the structural analysis of the member using the physical property value calculated in the thermal property value-physical property value conversion process (S74), thereby under the conditions assumed by the user. The stress and displacement of the member are calculated (S76). The details of the structure analysis process (S76) are the same as the structure analysis process of the first embodiment shown in FIG. 19, and thus detailed description thereof is omitted here.

  The safety factor calculation unit 86 calculates the safety factor of each element (S77). FIG. 38 shows a detailed flowchart of the safety factor calculation process (S77) according to the third embodiment. The safety factor calculation unit 86 acquires strength information including the strength of each element from the structure analysis unit 66 (S91). The safety factor calculation unit 86 acquires the stress information of each element from the structural analysis result storage unit 44 (S92).

  The safety factor calculation unit 86 calculates the safety factor of each element by dividing the strength of each element by the stress of the corresponding element (S93).

  Here, the strength has orientation as described above. Stress can also be calculated for each direction. Therefore, for example, the safety factor of each element is calculated for each of the fiber direction of each element and the direction perpendicular thereto, and the smaller one is defined as the safety factor of the element.

  In calculating the safety factor, for example, the intensity obtained by converting the intensity in each direction into one magnitude may be used. In this case, the absolute value of the stress generated in each element may be used as the stress used for calculating the safety factor.

  The safety factor calculation unit 86 stores the calculated safety factor of each element in the structural analysis result storage unit 44 (S94).

  Refer to FIG. 36 again. The display control unit 70 causes the display unit 22 to display, for example, a contour diagram in which the difference in magnitude of the safety factor of each element is associated with a change in color, a list of absolute values of the safety factor for each element, S78), the process is terminated.

  As mentioned above, in this Embodiment, the safety factor for every element of the member containing a fiber is calculated. Therefore, a highly accurate simulation of the safety factor can be realized. Further, since the elastic modulus and strength for each element used for calculating such a safety factor are calculated based on thermal analysis, the time required for the calculation is shorter than that calculated by flow analysis or the like. Therefore, the safety factor of the member can be calculated in a short time. Furthermore, the safety factor in consideration of the fiber orientation of each element can be calculated. Therefore, it is possible to calculate the safety factor with high accuracy, and it is possible to design the product and the mold for injection molding the product with high accuracy.

  In each embodiment of the present invention, the analysis result is calculated for each element. However, the analysis result may be calculated for each node that is an intersection of boundaries dividing each element. This makes it possible to select an appropriate calculation method as appropriate.

  INDUSTRIAL APPLICABILITY The present invention can be used for structural analysis of a member or the like that is made of a material that includes a fibrous substance and is injection-molded.

The figure which shows the external appearance of the structural-analysis apparatus which concerns on Embodiment 1 of this invention. 1 is a block diagram of a structural analysis apparatus according to Embodiment 1. FIG. FIG. 5 shows a specific example of element information according to the first embodiment. FIG. 5 is a diagram showing a specific example of thermal analysis condition information according to the first embodiment. FIG. 4 is a diagram showing a specific example of heat flux vector information according to the first embodiment. FIG. 4 is a diagram showing a specific example of temperature information according to the first embodiment. FIG. 6 shows a specific example of conversion condition information according to the first embodiment. FIG. 4 is a diagram showing a specific example of physical property information according to Embodiment 1. FIG. 4 is a diagram showing a specific example of structural analysis result information according to the first embodiment. FIG. 3 is a block diagram showing details of a conversion unit according to the first embodiment. 5 is a flowchart of processing executed by the structural analysis apparatus according to the first embodiment. The figure which shows the example which divided | segmented the element of the fan 90a as a member. The flowchart which shows the detail of thermal analysis process S3. The figure which shows a part of heat flux vector of each element obtained by the thermal analysis of the fan. 3 is a photograph showing the front of the fan exemplified in Embodiment 1. FIG. The figure which expands and shows the image by the X-ray CT apparatus of the rectangular part shown by FIG. The figure which shows the orientation of the fiber of the fan produced based on the image by an X-ray CT apparatus. 5 is a flowchart showing details of conversion processing according to the first embodiment. The flowchart which shows the detail of structure analysis process S5. The figure which shows the external appearance of the structural analysis apparatus which concerns on Embodiment 2 of this invention. FIG. 4 is a block diagram of a structural analysis apparatus according to a second embodiment. FIG. 10 is a diagram showing a specific example of element information according to the second embodiment. The figure which shows the specific example of the thermal analysis condition information which concerns on Embodiment 2. FIG. FIG. 6 is a diagram showing a specific example of temperature gradient information according to the second embodiment. The figure which shows the specific example of the heat flux vector information which concerns on Embodiment 2. FIG. FIG. 6 shows a specific example of temperature information according to the second embodiment. FIG. 10 is a diagram showing a specific example of conversion condition information according to the second embodiment. FIG. 6 is a block diagram showing details of a conversion unit according to the second embodiment. The figure which shows the temperature distribution calculated by the thermal analysis by using two gates as a heat source. 10 is a flowchart of processing executed by the structural analysis apparatus according to Embodiment 2. 10 is a flowchart showing details of thermal analysis processing S43 according to the second embodiment. 9 is a flowchart showing details of conversion processing S44 of the second embodiment. FIG. 6 is a block diagram of a structural analysis device 20c according to a third embodiment. FIG. 10 shows a specific example of conversion condition information according to the third embodiment. FIG. 9 is a block diagram showing details of a conversion unit according to the third embodiment. 10 is a flowchart of processing executed by the structural analysis apparatus according to the third embodiment. 10 is a flowchart showing details of thermal characteristic value-intensity conversion processing according to Embodiment 3. 10 is a flowchart showing details of a safety factor calculation process S77 according to the third embodiment.

Explanation of symbols

  20a, 20b, 20c structure analysis device, 22 display unit, 24 input unit, 26 CAD device, 32 element storage unit, 34 thermal analysis condition storage unit, 36 thermal characteristic storage unit, 38 conversion condition storage unit, 40 physical property storage unit, 42 structural analysis condition storage unit, 44 structural analysis result storage unit, 52 input information acquisition unit, 56 shape acquisition unit, 58 element division unit, 60a, 60b thermal analysis unit, 64a, 64b, 64c conversion unit, 66 structural analysis unit, 70 display control unit, 72a, 72b thermal characteristic information acquisition unit, 74a heat flux vector information acquisition unit, 74b temperature information acquisition unit, 74c temperature gradient information acquisition unit, 78 conversion condition information acquisition unit, 80 physical property value calculation unit, 82 weld Position specifying part, 84a, 84b Strength calculation part, 86 Safety factor calculation part.

Claims (7)

A structure analysis method for a member that is injection-molded using a material containing a fibrous substance,
A shape acquisition step of acquiring shape information of the member;
An element dividing step of dividing the member into a plurality of elements and generating element information indicating each divided element;
Using each element indicated by the element information, a thermal characteristic value indicating the thermal characteristic of the member is calculated by performing a thermal analysis assuming that there is a heat source in a portion corresponding to the gate of the mold into which the material is poured, and calculating A thermal analysis step for generating thermal characteristic information including the thermal characteristic value,
A conversion step of acquiring the thermal characteristic information and converting the acquired thermal characteristic information into physical property information including physical property values used for structural analysis;
It looks including the structural analysis step of performing a structural analysis of the member by using the above physical property values included in the property information, and the respective elements which the element information indicating,
In the thermal analysis step, the thermal characteristic information including the heat flux vector information indicating the heat flux vector of each element is generated,
In the conversion step,
Obtaining the thermal characteristic information including the heat flux vector;
Converting the heat flux vector into physical property information including physical property values in consideration of the orientation of the fibrous material by using the orientation of the fibrous material as an orientation of the fibrous material . In the thermal analysis step, the thermal characteristic information further including temperature information indicating the temperature of each element is generated,
The conversion step is
Obtaining the thermal characteristic information including the temperature information;
Obtaining conversion condition information including a maximum value and a minimum value of physical property values in the member;
The structure according to claim 1, further comprising: converting the temperature in a one-to-one correspondence with the physical property value so that the higher the temperature included in the temperature information is, the larger the physical property value of the element is. analysis method. 3. The stress and / or displacement of each element according to claim 1, wherein, in the structural analysis step, the stress and / or displacement of each element is calculated with reference to a boundary condition set by a user and the calculated physical property value of each element. Structural analysis method. The conversion step is
Obtaining conversion condition information including a maximum value and a minimum value of elastic modulus and a maximum value and a minimum value of density in the member;
The maximum temperature included in the temperature information is associated with the maximum value of the elastic modulus, the minimum temperature is associated with the minimum value of the elastic modulus, the maximum temperature and the minimum temperature are weighted, and the temperature of each element is determined. Calculating a value obtained by weighting the maximum value of the elastic modulus and the minimum value of the elastic modulus as obtained when the temperature of each element is obtained, as the elastic modulus of each element. ,
Converting the heat flux vector into physical property information including the elastic modulus of each element in consideration of the orientation of the fibrous material by setting the orientation of the fibrous material, and
The maximum temperature included in the temperature information is associated with the maximum value of the density, the minimum temperature is associated with the minimum value of the density, and the temperature of each element is obtained by weighting the maximum temperature and the minimum temperature. And calculating a value obtained by weighting the maximum value of the density and the minimum value of the density with the same weight as when the temperature of each element is obtained, as the density of each element. The structural analysis method according to claim 2 or claim 3. The conversion step is
Obtaining conversion condition information including a maximum value and a minimum value of physical property values in the member, and a maximum value and a minimum value of strength in the member;
The maximum temperature included in the temperature information is associated with the maximum value of the physical property value, the minimum temperature is associated with the minimum value of the physical property value, and the maximum temperature and the minimum temperature are respectively weighted, and the temperature of each element A value obtained by weighting the maximum value of the physical property value and the minimum value of the physical property value in the same weight as when the temperature of each element is obtained, as the physical property value of each element. When,
The maximum temperature included in the temperature information is associated with the maximum value of the intensity, the minimum temperature is associated with the minimum value of the intensity, and the temperature of each element is obtained by weighting the maximum temperature and the minimum temperature. And calculating the value obtained by weighting the maximum value of the structural characteristic value and the minimum value of the intensity as in the case of obtaining the temperature of each element as the intensity of each element. ,
In the structural analysis step, the stress of each element is calculated with reference to preset boundary conditions and the calculated physical property values of each element.
The structural analysis method according to claim 4, further comprising: calculating a safety factor of each element by dividing the strength of each element by the stress. The conversion step is
Obtaining conversion condition information further including an intensity magnification indicating how much strength of the portion where the weld has occurred in the material compared to the strength of the material;
Determining whether the temperature of each element included in the temperature information is equal to or lower than the minimum temperature, and identifying an element equal to or lower than the minimum temperature as a weld position;
For the element identified as the weld position, the intensity obtained based on the temperature information is multiplied by the intensity magnification to correct the weld position intensity, and the intensity information including the corrected weld position intensity is generated. The structural analysis method according to claim 5, further comprising: In the thermal analysis step, the thermal characteristic information including temperature gradient information indicating a temperature gradient of each element is generated,
The conversion step is
Obtaining the thermal characteristic information including the temperature gradient information;
Obtaining conversion condition information further including an intensity magnification indicating how much the strength of the portion where the weld has occurred in the material compared to the strength of the material;
Determining whether the temperature gradient of each of the elements included in the temperature gradient information is less than or equal to a threshold, and identifying an element that is less than or equal to the threshold as a weld position;
For the element identified as the weld position, the intensity obtained based on the temperature information is multiplied by the intensity magnification to correct the weld position intensity, and the intensity information including the corrected weld position intensity is generated. The structural analysis method according to claim 5, further comprising:

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