JP2003271678A - Numerical analysis method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a numerical analysis method and device capable of accurately estimating a flow condition of a flow matter, especially the flow condition of an extrusion molded material in extrusion molding. <P>SOLUTION: This numerical analysis method for simulating the flow behavior of the flow matter when the flow matter is filled in an analysis target by a computer with the usage of an analysis model wherein the shape of the analysis target is divided into a plurality of minute elements is provided with a process for setting an initial value of a flowability parameter for prescribing flow easiness of the flow matter with respect to the minute element, a process for analyzing while the flow matter is filled in the analysis target, a process for relating the respective minute elements with minute elements on the upstream side, a process for varying the flowability parameter for each of the minute elements based on the variation of a specified parameter with respect to the minute elements on the upstream side, and a process for analyzing again while the flow matter is filled in the analysis target based on the varied flowability parameter. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method, an apparatus and a storage medium for analyzing a fluid flow behavior by numerical analysis by a computer.

[0002]

2. Description of the Related Art Generally, an analysis method for reproducing a fluid flow process in which a fluid flows through a flow path by computer simulation is utilized in various fields such as injection molding and filling of liquid crystal panels. In particular, the simulation of the flow process of the injection molding material in injection molding has been widely put to practical use in the development of injection molded products.

The analysis method is described in a large number of documents such as Kazumori Funazu supervised molding process of polymer / composite material, Shinyamasha Cytec. On the other hand, these injection molding process analysis methods contribute to high quality, efficiency, and cost reduction in product development of injection molded products and the like. Regarding the utilization method and the like, for example, JP-A-3-224712, JP-A-4-152120, and JP-A-4-305.
No. 424 and Japanese Patent Laid-Open No. 4-331125.

In general injection molding analysis, the flow resistances of the mold sprue, runner, and cavity are determined by the sprue, runner,
It is calculated based on the cavity shape and the viscosity of the fluid. The flow resistance is an index indicating the ease of flow in the cavity. For example, in the case of a molded product having a thinner wall thickness than the maximum size of the molded product, the flow resistance in the cavity is determined by the following formula. (Flow resistance) =-1 / (wall thickness) ² / (12 × (viscosity)) (1) The flow state in the cavity is expressed as follows using the above flow resistance. (Flow velocity) = 1 / (Flow resistance) × (Pressure gradient) (2) In the injection molding analysis, first, the molded product is divided into minute elements such as a triangle, a quadrangle, a tetrahedron, and a hexahedron, and each minute element is divided. The above flow resistance is determined by using the Navier-Stokes equation, which is well known as a fluid motion equation, or a simplified equation thereof, and a basic equation called a mass conservation law or an energy equation. Based on, the well-known numerical calculation methods such as the finite element method and the difference method are used to calculate the pressure and flow velocity of each minute element. When the result of the analysis shows that the molding is impossible at the maximum value of the set pressure, measures such as increasing the wall thickness of the analysis target are taken.

In the numerical analysis of the injection molding process, in the flow resistance calculation, the viscosity of the molding material is set as the input condition as shown in the equation (1). At this time, the viscosity is the temperature of the fluid, the shear rate, the pressure, etc. Often defined as a function of. For example, in injection molding of resin materials, viscosity is often considered as a function of temperature and shear rate, and is often defined by the following equation.

(Viscosity) = A × (shear rate) ^B × exp (C × (temperature)) (3) where A, B and C are material constants measured using a viscometer for each resin material. Yes, it is stored in the material database and is read and used during analysis.

In general, an injection-molded product has a structure in which an uneven thickness portion and a branch portion are combined, so that there are contraction, expansion, and branch flow due to the shape. In this case, the injection molding during flow is performed. It is affected by the molecular orientation and stretching of the material, and the elastic effect.

In particular, liquid crystal polymers are formed by rigid molecules and have the property of promoting molecular orientation when subjected to shearing force. It is known that the polymer behaves distinctly different from that of the polymer.

Various constitutive equations have been proposed in order to express the flow behavior peculiar to the fluid as described above, but the numerical calculation method becomes complicated and the numerical stability in the high-speed region such as injection molding is improved. Due to the problem, it was difficult to use practically.

[0010]

In view of these circumstances, the present invention provides a numerical analysis method for predicting the flow state of a fluid, in particular, the flow behavior of an injection molding material in injection molding with high accuracy using an easy calculation method, and The purpose is to provide a device.

[0011]

In order to achieve the above object, according to the present invention, the flow behavior of a fluid when the fluid is filled in the analysis object is determined by the shape of the analysis object. A numerical analysis method for simulating by a computer using an analysis model divided into a plurality of minute elements, the step of setting an initial value of a fluidity parameter that defines the ease of flow of a fluid in a minute element, and an analysis target Based on the correlation between each microelement and its upstream microelement, the step of analyzing the process of filling the fluid with the microelement, the step of associating each microelement with its upstream microelement, A numerical value characterized by having a step of changing the fluidity parameter for each time, and a step of performing again the analysis of the process in which the fluid is filled in the analysis object based on the changed fluidity parameter析方 there is provided a method.

Further, in a preferred aspect of the present invention, in the step of changing the fluidity parameter for each microelement, the change in the specific parameter is caused by the flow direction, flow rate, flow rate gradient, shear rate and It is a numerical analysis method which is a change in one or more parameters selected from the shear stress and the wall thickness of an object to be analyzed in the minute element.

In a preferred embodiment of the present invention, in the step of changing the fluidity parameter for each microelement, the flow direction of the fluid, the flow velocity, the flow velocity gradient, the shear rate and the shear stress, and the analysis of the microelement. This is a numerical analysis method in which a fluidity parameter for each microelement is multiplied by a weighting function with the change in each microelement and the microelement upstream of the wall thickness of the object as a parameter.

A preferred embodiment of the present invention is a numerical analysis method in which the fluidity parameter is flow resistance.

A preferred embodiment of the present invention is a numerical analysis method for analyzing the behavior of the injection molding material when the object to be analyzed is filled with the injection molding material in the injection molding process.

Further, according to the present invention, there is provided a numerical analysis device for simulating a flow behavior of a fluid when the fluid is filled in the fluid to be analyzed, wherein the shape of the fluid to be analyzed is divided into a plurality of minute shapes. Analysis condition setting means for setting the analysis conditions including the analysis model divided into elements, initial parameter setting means for setting the initial value of the fluidity parameter defining the flowability of the fluid in each minute element, and the analysis target The analysis execution means for analyzing the process in which the fluid is filled in, the flow history analysis means for associating each minute element with its upstream minute element, and the associating each minute element with its upstream minute element A fluidity parameter changing means for changing the fluidity parameter for each minute element is provided based on the numerical analysis apparatus.

Further, in a preferred aspect of the present invention, the fluidity parameter changing means is selected from a flow direction, a flow velocity, a flow velocity gradient, a shear velocity and a shear stress of the fluid and a wall thickness of an object to be analyzed in the minute element. The numerical analysis device is means for changing the fluidity parameter of each microelement based on the change in each microelement and the microelement upstream of the one or more parameters.

Further, in a preferred aspect of the present invention, the fluidity parameter changing means determines the flow direction, flow velocity, flow velocity gradient, shear velocity and shear stress of the fluid and the wall thickness of the analysis object in the microelement. It is a numerical analysis device that is a means for multiplying a fluidity parameter for each microelement by a weighting function having a change in each microelement and a microelement upstream thereof as a parameter.

A preferred embodiment of the present invention is a numerical analysis device in which the fluidity parameter is flow resistance.

A preferred embodiment of the present invention is a numerical analysis apparatus for analyzing the behavior of the injection molding material when the object to be analyzed is filled with the injection molding material in the injection molding process.

According to the present invention, the flow behavior of the fluid when the fluid is filled in the fluid to be analyzed is analyzed by using an analytical model in which the shape of the fluid to be analyzed is divided into a plurality of minute elements. There is provided a computer-executable numerical analysis program that can be executed by a computer to execute each step of the numerical analysis method described in any of the above.

According to the present invention, there is also provided a computer-readable storage medium storing the above program.

Further, according to the present invention, the injection molding process of the injection molded article is analyzed by using the above numerical analysis method, the manufacturing parameters are finally determined based on the analysis result, and the manufacturing parameters are finally determined based on the finally determined manufacturing parameters. A method of manufacturing an injection-molded article for manufacturing an injection-molded article is provided.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments in which the present invention is applied to injection molding analysis will be described below.

In this case, the object to be analyzed is the shape of the injection-molded product molded by injection molding, in other words, the shape of the cavity portion engraved inside the mold used for injection molding.

As the fluidity parameter in the present invention, if it is a parameter that defines the flowability of the fluid,
Although any material may be used, flow conductance or flow resistance is preferably used. The case where the flow resistance is used will be described below.

First, the initial value of the flow resistance is obtained and set for each minute element. The initial value of the flow resistance may be obtained by any method, but for example, the value calculated by the following formula for each minute element from the wall thickness and temperature of each cavity and the shear rate can be used. . (Flow resistance) =-(12 x (viscosity)) / (wall thickness) ² (4) (Viscosity) = A x (shear rate) ^B x exp (C x (temperature)) (5) In the thickness direction When considering the situation where the viscosity is unevenly distributed, the flow resistance may be expressed by the following equation in the form of integral in the thickness direction as is generally done.

[0028]

[Equation 1]

The flow resistance may be given by the pressure at the flow front portion, or the flow resistance may be given by changing the flow rate distribution at the flow front portion.

Next, the process of filling the object to be analyzed with the fluid is analyzed to associate each microelement with the microelement upstream thereof. That is, for a small element,
The history of the flow, from which minute element the fluid is flowing, is obtained. This association may be obtained retroactively up to several stages, but in order to speed up the calculation, it is preferable to obtain only the association with the immediately preceding minute element. This association may be performed based on any calculation. For example, the average pressure of all the microelements adjacent to the microelement to be analyzed is compared, and the microelement with the highest pressure moves to the microelement. Should be regarded as inflowing and associated.

Further, based on this association, the flow resistance is changed for each micro element based on the change of a specific parameter in each micro element and the micro element upstream thereof. Although various parameters can be used as the specific parameters, they are selected from the flow direction of the fluid, the flow velocity, the flow velocity gradient, the shear velocity and the shear stress, and the wall thickness of the analysis object in the minute element. It is preferable to use one or more of the parameters specified above. This is because these parameters have a great influence on the anisotropy of flow. Of these, it is also preferable to use two or more parameters in combination.

The flow resistance may be changed for all the microelements, or may be set only for the microelements having a great influence of the flow anisotropy. For example,
The flow anisotropy has a large effect on the part where the analysis target is branched, while on the part where the flow direction is forcibly changed, such as on a straight line part or a corner part, the flow anisotropy is affected. The impact is small. Therefore, it is preferable to change the flow resistance only for the portion where the analysis target is branched.

To change the flow resistance, it is preferable to multiply the flow resistance by the following weighting function. (Weight function) = A x Θ + B x THK + C x VEL + D x SHR + E x STR (7) where Θ is the normalized angle between the flow direction of each microelement and its upstream flow direction, THK is the average value of the target shape wall thickness given to each micro element and the target shape wall thickness given to the element that is upstream thereof, and VEL is the in-plane flow due to the flow velocity of each micro element and its upstream flow velocity. Velocity gradient, SHR is the shear velocity gradient due to the shear velocity which is the velocity gradient in the thickness direction of each microelement and its upstream shear rate, STR is the shear stress gradient due to the shear stress of each microelement and its upstream shear stress, A, B,
C, D, and E are parameters determined by experiments.

Further, the weighting function to be applied to the flow resistance is not limited to the linear equation as in the above (7), and a polynomial or an exponential function may be used. Further, the inertial effect depending on the velocity gradient in the in-plane direction, which is often omitted in the injection molding analysis, is pseudo-expressed by using the product of the flow velocity and the flow velocity gradient in the in-plane direction as a parameter. It becomes possible.

Any method may be used as the method of determining the coefficient of the weighting function. For example, injection molding of the shape of the molded product shown in FIG. 1 is performed, and the progress of filling in the mold is measured using a technique such as the short shot method that is generally performed. The short shot method is a method of observing the progress of filling by cooling with a small amount of injection material to be solidified during filling and taking out. When the effect of wall thickness change is considered, the wall thickness is changed, and when the material velocity, velocity gradient, and shear stress are considered, the injection speed is changed while the short shot method is used for measurement. While comparing the results of the actual injection molding thus obtained with the numerical analysis results, the numerical analysis is repeated by appropriately changing A, B, C, D, and E, and the numerical analysis results match the actual measurement results. A,
B, C, D, E can be found. A, B, C,
It is desirable to measure D and E for each material and store it in the database. FIG. 1 is an example in which the progress state of the flow front obtained by the short shot method is displayed in an overlapping manner, which is called a filling pattern. By comparing this pattern with the pattern obtained from the numerical analysis result, the above A,
B, C, D, E can be determined.

By performing the analysis of the process in which the fluid is filled in the object to be analyzed based on the changed fluid resistance,
Flow analysis can be performed in consideration of flow anisotropy,
Highly accurate analysis results can be obtained.

FIG. 2 is a flow chart showing the schematic procedure of one embodiment when the present invention is applied to injection molding analysis. The numerical analysis method according to the present embodiment includes a data input / preparation process (steps 1 and 2), an analysis execution process (steps 3 to 6), and an analysis result display process (step 7) that are performed in a normal numerical analysis. Data input
The preparation process is divided into step 1 for inputting analysis conditions and step 2 for setting initial flow resistance, and the analysis execution process is step 3 for flow analysis, steps 4 and 5 for calculation of flow resistance change, It is divided into step 6 for performing the filling process.

Further, FIG. 3 is a block diagram of the analysis apparatus used in the present embodiment, wherein the analysis condition setting means 101, the initial parameter setting means 102, the analysis executing means 103, the flow history analysis means 104, and the fluidity parameter changing means. 105,
An arithmetic unit 100 for performing an analytical arithmetic process including a filling progress unit 106 and an analysis result output unit 107, a data storage unit 110 including a memory and a hard disk for storing analysis data and software, a keyboard, a mouse, a digitizer, and a three-dimensional shape measurement. An analysis condition input device 120 including a device and the like, a display, a printer, an output device 130 including a stereolithography device, and the like are provided. Each of these means is realized in the form of a function or subroutine on hardware constructed by a CPU and a memory of an arithmetic unit (computer).

The following example is for the purpose of explaining the basic method of carrying out the present invention, and as shown in FIG.
Taking the injection molding into a V-shaped cavity as an example, the case where the present invention is applied to the filling analysis during injection molding using the flow direction as a specific parameter used for the weighting function will be described.

First, in step 1, the analysis condition input device 12
With 0, an analysis condition including at least an analysis model in which the shape of the analysis object is divided into minute elements is further input, and if necessary, an analysis condition including parameters such as the viscosity of the molding material, the injection temperature, and the injection pressure is input. Here, as shown in FIG. 5, the shape of the injection-molded product of FIG. 4 was divided into hexahedral microelements. The weighting function parameter of the molding material is also used as the analysis condition input device 120.
Enter more. These analysis condition inputs may be input by selecting them from electronic information that has been input to the analysis condition input device 120 in advance and stored in the data storage device 110 as a database. Further, the gate portion 7 is input as the gate position where the material is injected. The input analysis condition data is held in the memory and, if necessary, saved in the data storage device 110 by the analysis condition setting means 101. The analysis model can be constructed on the memory by reading the already created one on the memory or automatically creating it from CAD data representing the outer shape or the like.

Next, in step 2, the data storage device 110
The analysis condition data is read into the memory of the arithmetic unit 100, and the initial parameter setting means 102 sets the initial flow resistance for each minute element.

Next, in step 3, based on the analysis condition data and the initial flow resistance set, the analysis executing means 1
The injection molding flow analysis is executed by 03. In the injection molding flow analysis, usually, the period from the start of injection molding to the time when the fluid is completely filled in all the minute elements included in the analysis model is divided into several steps for calculation. As a result, at each calculation step, the filling progress state in the analysis model,
The analysis results of the material flow direction, pressure, temperature, etc. in each minute element are obtained, and the arithmetic unit 100 is used as the previous analysis result.
In the memory or the data storage device 110.
Here, as the analysis executing means 103, a means using a numerical analysis method such as a finite element method, a boundary element method, a difference method, and a finite volume method may be used.

Next, at step 4, the flow history analysis means 104 determines the upstream microelements for each microelement from the above analysis results, and the calculation result is the arithmetic unit 10.
0 memory or data storage device 110.

Next, at step 5, the flow resistance calculating means 1
According to 05, a weighting function was calculated by using the angle formed by the flow direction of the molding material in each micro element and the flow direction of the molding material in the micro element upstream thereof, and the flow resistance of each micro element was multiplied by the weight function. The value is calculated, and the calculation result is recorded in the memory of the computing unit 100 or the data storage device 110. The flow resistance multiplied by the calculated weight function is reset for each minute element.

Next, returning to step 3, the analysis execution means 103 executes the injection molding flow analysis again based on the flow resistance. As a result, the flow analysis result is obtained, but the conditions such as the flow direction presupposed in the calculation of this step are based on the initial value of the flow resistance, and therefore there is a possibility that the error is large. Therefore, based on the analysis results of the flow direction, pressure, temperature, etc. obtained by the calculation in this step, the flow returns to step 4 again, and the flow resistance is recalculated. In this way, steps 3, 4 and 5 are repeated until the calculation results converge. Specifically, the difference between the analysis result of this time and the analysis result of the previous time is calculated, and it is determined whether or not it is within a predetermined difference. If it is not within the predetermined difference, the analysis result of this time is compared with the previous analysis result. Is recorded in the memory of the arithmetic operation unit 100 or the data storage device 110, and the procedure returns to step 4 to repeat the analysis.

When the difference between the current analysis result and the previous analysis result obtained as a result of the analysis is within a predetermined difference, it is considered that the analysis has converged, and in this analysis, filling of all minute elements is completed. It is determined whether or not. If the filling of all the minute elements is not completed, the filling progressing means 10 is performed in step 6.
The filling is advanced by 6, and the process is repeated from step 3.

When all the minute elements have been filled, the analysis result output means 109 outputs the analysis result, and in step 7, the analysis result output device 120 outputs the pressure, temperature,
The analysis results such as speed are output by a method such as a contour map display, numerical data output, graph output, vector display. FIG. 6 shows the flow velocity vector of the material in a state where the mold cavity portion is filled with 60% of its volume. The direction of the arrow represents the flow direction, and the longer the arrow, the higher the flow velocity. It represents. FIG. 7 is a filling pattern diagram showing the filling time of each minute element in a contour line in a state where all the minute elements are filled.

[0048]

EXAMPLE An example in which the method and apparatus for predicting and analyzing a physical phenomenon according to the present invention is applied to a practical product will be described below as an example applied to an injection-molded product shown in FIG.

First, in order to obtain the anisotropy coefficient, an injection molding experiment was conducted using the test piece shown in FIG. 1, and the following was determined using the short shot method.

(Weight function) = A × Θ + B × THK + C × VEL + D × SHR + E × STR (8) A: 5.0, B: 0.5, C: 0.2, D: 1.0, E: 0.7 Next, in step 1, As shown in FIG. 9, the shape of the molded product was divided into triangular or quadrangular minute elements 11, and the positional coordinate values of the respective minute element vertices were input by the analysis condition input device 120. As another analysis condition, gate position 1
2. Molding conditions such as filling time, injection temperature, mold temperature, and physical properties such as viscosity and thermal conductivity of molding material, and other input conditions used in ordinary injection molding flow analysis were input.

The following steps are repeated throughout the filling process. In step 2, from the thickness and viscosity of each part,
The initial flow resistance is calculated, the injection molding flow analysis is executed based on the initial flow resistance in step 3, and the flow direction change angle and the wall thickness change rate of each minute element and its upstream in the flow process are executed in step 4. The flow rate gradient change rate, shear rate change rate, and shear stress change rate were determined. Subsequently, in step 5, the flow resistance was determined by the above equation (8), and the process was returned to step 3 again to execute the injection molding flow analysis by the flow resistance. By repeating Step 3 to Step 6 six times, the error between the maximum value (or the average value or the integral value) of the pressure distribution in the flow before the iteration converged within 1%, and the converged solution was obtained. In step 6, the filling was advanced. By repeating the above steps until the filling is completed, the filling pattern shown in FIG. 10 was obtained. The filling pressure at this time was found to be 80 MPa at maximum, and since it was within the maximum possible pressure range of the injection molding machine, it was judged that injection molding was possible, and when an actual mold was manufactured and molded,
It could be molded without problems.

[0052]

According to the present invention, it is possible to significantly improve the accuracy of analysis of behavior when a fluid is filled in an object. For example, this makes it possible to simulate the injection molding process more accurately, and improves the efficiency of mold design and product design by setting the appropriate gate position and wall thickness, shortening the product development period and It can contribute to the improvement of quality. In particular, in the numerical analysis of the injection molding process of a material having a strong anisotropy due to the flow orientation such as liquid crystal resin, the analysis accuracy can be significantly improved as compared with the conventional numerical analysis method and apparatus.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an example of the shape of an injection mold cavity, which is used when determining the flow resistance from the characteristics of the shape and flow behavior.

FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 3 is an analysis device used in an example of an embodiment of the present invention.

FIG. 4 is an injection molded article shape used in an example of an embodiment of the present invention.

5 is a conceptual diagram showing a state in which the injection-molded article of FIG. 4 is divided into minute elements.

6 is a conceptual diagram showing a state in which 60% of the volume of the injection-molded article of FIG. 4 is filled.

7 is a filling pattern diagram showing a state in which the flow front moves during filling of the injection-molded article of FIG. 4 obtained by the flow analysis method of the present invention.

FIG. 8 is an injection-molded product shape used in an example of the present invention.

9 is a conceptual diagram showing a state in which the injection-molded product shape of FIG. 8 is divided into minute elements.

FIG. 10 FIG. 8 obtained by the flow analysis method of the present invention.
FIG. 6 is a filling pattern diagram showing a state in which the flow front moves when the injection-molded article is filled.

[Explanation of symbols]

100 ... Arithmetic device 101 ... Analysis condition setting means 102 ... Initial parameter setting means 103 ... Analysis execution means 104 ... Flow history analysis means 105 ... Fluidity parameter changing means 106 ... Filling progress means 107 ... Analysis result output means 110 ... Data storage device 120 ... Analysis condition input device 130 ... Output device 1 ... Cavity shape 2 ... Gate position 3 ... Short shot Flow tip position obtained by the method 4 ... Injection-molded product 5 ... Hexahedron microelement 51 ... Gate position 6 ... Injection-molded product 7 ... Gate position 8 ... 60% filling Flow tip position 61 ... Unfilled portion at 60% filling 62 ... Velocity vector at 60% filling 63 ... Filled portion 9 at 60% filling 9 ... Filling pattern 10 obtained by numerical analysis・Injection molded article shape 11 ... microelements 12 ... gate position 13 filling patterns obtained from ... Numerical Analysis

Claims (13)

[Claims] 1. A numerical analysis for simulating a flow behavior of a fluid when the fluid is filled into the analysis object by a computer using an analysis model in which the shape of the analysis object is divided into a plurality of minute elements. A method of setting an initial value of a fluidity parameter that defines the flowability of a fluid in a micro element, a step of analyzing a process in which a fluid is filled in an analysis target, and each micro element The step of associating the micro-elements with the upstream micro-elements, the step of changing the fluidity parameter for each micro-element based on the change of a specific parameter in each micro-element and the micro-elements upstream thereof, and the modified flow And a step of re-analyzing the process in which the fluid is filled in the analysis object based on the sex parameter. 2. In the step of changing the fluidity parameter for each microelement, the change in the specific parameter is caused by the flow direction of the fluid, the flow velocity, the flow velocity gradient, the shear rate and the shear stress, and the change in the microelement. The numerical analysis method according to claim 1, which is a change in one or more parameters selected from the wall thickness of the analysis target. 3. In the step of changing the fluidity parameter for each microelement, the flow direction, flow velocity, flow velocity gradient, shear rate and shear stress of the fluid and the wall thickness of the analysis object in the microelement are measured. The numerical analysis method according to claim 2, wherein a weighting function having a change in each micro element and a micro element upstream thereof as a parameter is applied to the fluidity parameter of each micro element. 4. The numerical analysis method according to claim 1, wherein the fluidity parameter is flow resistance. 5. The numerical analysis method according to claim 1, wherein the behavior of the injection molding material when the object to be analyzed is filled with the injection molding material in the injection molding process. 6. A numerical analysis device for simulating, by a computer, the flow behavior of a fluid when the fluid is filled in the analysis object, wherein the analysis model is obtained by dividing the shape of the analysis object into a plurality of minute elements. The analysis condition setting means for setting the analysis conditions including the above, the initial parameter setting means for setting the initial value of the fluidity parameter defining the flowability of the fluid in each microelement, and the fluid to be analyzed are filled with the fluid. Based on the correlation between the analysis execution means for analyzing the process, the flow history analysis means for associating each micro element with the upstream micro element, and each micro element based on the association between each micro element and the upstream micro element. And a fluidity parameter changing means for changing the fluidity parameter. 7. The fluidity parameter changing means comprises one or more parameters selected from a flow direction, a flow velocity, a flow velocity gradient, a shear velocity and a shear stress of a fluid, and a wall thickness of an object to be analyzed in the minute element. 7. The numerical analysis device according to claim 6, which is a means for changing the fluidity parameter of each microelement based on the change in each microelement and the microelement upstream thereof. 8. A fluidity parameter changing means is provided for each microelement and its upstream of a flow direction, a flow velocity, a flow velocity gradient, a shear velocity and a shear stress of a fluid and a wall thickness of an object to be analyzed in the microelement. The numerical analysis device according to claim 7, which is a means for multiplying a fluidity parameter for each minute element by a weighting function having a change in the minute element as a parameter. 9. The numerical analysis device according to claim 6, wherein the fluidity parameter is flow resistance. 10. The numerical analysis device according to claim 6, which analyzes the behavior of the injection molding material when the injection molding material is filled with the injection molding material in the injection molding process. 11. A numerical analysis for simulating, by a computer, a flow behavior of a fluid when the fluid is filled in the analysis object by using a computer using an analysis model in which the shape of the analysis object is divided into a plurality of minute elements. A computer-executable program that executes each step of the numerical analysis method according to claim 1. 12. A computer-readable storage medium storing the program according to claim 11. 13. An injection molding process of an injection molded product is analyzed using the numerical analysis method according to claim 5, manufacturing parameters are finally determined based on the analysis result, and injection is performed based on the finally determined manufacturing parameters. A method for producing an injection-molded article for producing a molded article.