JPWO2011108468A1 - Material constant estimation system and material constant estimation method - Google Patents

Abstract

A load condition providing unit that provides a load condition of a material test performed on a composite material including the first material and the second material, and controls the test of the composite material based on the load condition, and outputs a test result. A material that provides a test controller, a first temporary material constant temporarily set as a first material constant representing an unknown physical property of the first material, and a second material constant representing a known physical property of the second material A constant providing unit, a stress analysis unit for executing a stress analysis on the model of the composite material based on the load condition, the first temporary material constant, and the second material constant, and outputting an analysis result, a test result and an analysis An error determination unit that determines whether or not an error from the result is within a preset allowable range. The error determination unit determines the first temporary material constant as the first material constant when the error is within an allowable range.

Description

  The present invention relates to a material constant estimation system and a material constant estimation method for estimating a material constant of a material included in a composite material.

  When calculating the stress and strain of a composite material, finite element method stress analysis is performed by the multi-scale method. Finite element stress analysis by the multi-scale method is based on a macro analysis model that divides the entire composite material with coarse elements and a micro analysis model that divides the region where the material composition is periodic into fine elements. This is a method for calculating the stress and strain between the model and the micro model. Specifically, the equivalent stiffness of the micro model is calculated based on the material constants representing the stiffness and the like of each material constituting the micro model, assuming that the micro model is a homogeneous body. Using this equivalent stiffness as the stiffness of that part in the macro model, the macro model is subjected to stress analysis. Next, the displacement of the boundary of the micro model is extrapolated from the result of the stress analysis by the macro model, and the stress analysis of the micro model is performed. In this way, the stress and strain of the macro model and the micro model are obtained.

  Patent Document 1 discloses a method for simulating a heterogeneous material that simulates the behavior of a heterogeneous material having a microstructure in which a plurality of material phases having different material properties are dispersedly arranged using a discretized model. . This heterogeneous material simulation method has a first step to a third step. In the first step, the first discretized model that reproduces the microstructure of the heterogeneous material is deformed to perform a simulation calculation. Then, the superelastic potential when the microstructure of the heterogeneous material is made to be a homogeneous structure and the material constant based on this potential are determined. The second step uses a second discretized model that reproduces a structure containing a heterogeneous material by regarding the heterogeneous material as a homogeneous material, and based on the superelastic potential and the material constant, under a predetermined condition. Perform simulation calculations. The third step obtains the result of the strain or strain rate of the representative point of the arrangement portion of the heterogeneous material in the structure among the simulation calculation results performed using the second discretized model. Then, the displacement or displacement speed of the boundary region in the first discretized model is determined from this distortion or strain speed. This displacement or displacement speed is given to the first discretization model as a boundary condition of the first discretization model, and a simulation operation is performed to calculate a physical quantity that acts on a heterogeneous material having a microstructure.

Japanese Patent No. 4093994

  As in Patent Document 1, in the multi-scale method, simulation with a micro model is performed to obtain equivalent rigidity. At this time, it is assumed that the material constants representing the physical properties (mechanical characteristics, thermal characteristics, etc.) of each material constituting the micro model are known. For this reason, a material whose material constant is unknown is cut out from the composite material, and the material constant is determined by a material test. However, when it is difficult to cut out a target material from a composite material and perform a material test, it is difficult to determine an appropriate material constant of the material.

  Moreover, in the stress analysis of the micro model by the multi-scale method, the slip of the material interface cannot generally be considered. For this reason, in the case of a composite material in which even a slight slip or the like occurs at the material interface due to the load, the equivalent stiffness of the obtained macro model is used in the stress analysis method based on the material constants of each material constituting the micro model. The difference between the actual stiffness and the actual stiffness may increase.

  An object of the present invention is to provide a material constant estimation system capable of estimating an appropriate material constant for a material whose material constant is unknown in a composite material.

  The material constant estimation system of the present invention includes a load condition providing unit that provides a load condition of a material test performed on a composite material including a first material and a second material, and a test of the composite material based on the load condition. And a test control unit that outputs a test result, a first temporary material constant temporarily set as a first material constant representing an unknown physical property of the first material, and a known physical property of the second material Based on the material constant providing unit that provides the second material constant, the load condition, the first temporary material constant, and the second material constant, the stress analysis is performed on the composite material model, and the analysis result is output. A stress analysis unit; and an error determination unit that determines whether or not an error between the test result and the analysis result is within a preset allowable range. The error determination unit determines the first temporary material constant as the first material constant when the error is within an allowable range.

  The material constant estimation method of the present invention is performed on a first composite material including a first material and a second material, providing a first load condition of a material test, and based on the first load condition Controlling the first test of the first composite material, the first temporary material constant temporarily set as the first material constant representing the unknown physical property of the first material, and the known physical property of the second material Providing a second material constant; performing a first stress analysis on a model of the first composite material based on the first load condition, the first temporary material constant, and the second material constant; Determining whether the first error between the test result of the first test and the first analysis result of the first stress analysis is within an allowable range corresponding to the preset first test; If the error is within the allowable range corresponding to the first test, the first temporary material constant is And a step of determining the material constant.

  The material constant estimation system of the present invention can estimate an appropriate material constant for a material whose material constant is unknown in a composite material.

  The objects, effects, and features of the invention will become more apparent from the embodiments in conjunction with the accompanying drawings.

FIG. 1 is a block diagram showing a material constant estimation system 1 according to a first embodiment of the present invention. FIG. 2 is a block diagram illustrating a hardware configuration example in the embodiment of the estimation device 3. FIG. 3 is a flowchart showing the processing operation of the material constant estimation system 1 according to the embodiment of the present invention. FIG. 4 is a flowchart showing the processing operation of the material constant estimation system 1 according to the second embodiment of the present invention. FIG. 5 is a schematic diagram of a cross section of the composite material 100. FIG. 6 is a schematic diagram of the results of a tensile test performed on the composite material 100. FIG. 7 shows the composite material 100 shown by the finite element method analysis model. FIG. 8 is a schematic diagram of a stress-strain curve obtained by stress analysis of a tensile test performed on a model of the composite material 100. FIG. 9 is a schematic diagram illustrating a result in which an error between a test result and an analysis result is within an allowable range when the material constant is a certain value. FIG. 10 is a schematic cross-sectional view of a circuit board 500 that is a glass / epoxy resin composite material.

  Hereinafter, a material constant estimation system and a material constant estimation method according to embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment)
A first embodiment of the present invention will be described. FIG. 1 is a block diagram showing a material constant estimation system 1 according to a first embodiment of the present invention. The material constant estimation system 1 analyzes a composite material including two or more materials, and estimates a material constant of the material included in the composite material. Referring to FIG. 1, the material constant estimation system 1 includes a test apparatus 2 and an estimation apparatus 3.

  The test apparatus 2 executes a material test for calculating the material constant of the composite material based on the control of the estimation apparatus 3. The material constant is a specific value representing the physical properties (mechanical characteristics, thermal characteristics, etc.) of the material, and examples thereof include elastic modulus, Poisson's ratio, yield stress, plasticity coefficient, and viscosity constant. Material tests include mechanical property tests such as uniaxial tension / compression test, bending test, multi-axis test, vibration test, acceleration test, drop / fall weight test, thermal expansion coefficient measurement, heat conduction measurement, dynamic viscoelasticity measurement. And the like are exemplified. The test apparatus 2 performs a material test on the composite material, and measures test data (for example, load and displacement) related to physical properties for calculating a material constant of the composite material. The test apparatus 2 outputs the measured test data to the estimation apparatus 3.

  The estimation device 3 executes a stress analysis simulation for the composite material model. Then, the estimation device 3 appropriately estimates a material constant of a material whose material constant is unknown among a plurality of materials included in the composite material. Hereinafter, a material whose material constant is unknown is referred to as an unknown material, and a material whose material constant is known is referred to as a known material. The estimation device 3 has one unknown material constant that can be determined at a time among a plurality of materials included in the composite material. Accordingly, in the first embodiment, a case where a composite material including a plurality of known materials and one unknown material is analyzed will be described. The estimation device 3 includes a load condition providing unit 10, a test control unit 20, a material constant providing unit 30, a stress analysis unit 40, an error determination unit 50, and an output unit 60.

  The load condition providing unit 10 provides a load condition of a material test to be performed on the composite material to the test control unit 20 and the stress analysis unit 40 based on a user input. For example, when the material test executed by the test apparatus 2 is a uniaxial tensile test, the load condition includes a strain rate. The load condition providing unit 10 may provide a value input by the user as a load condition, store in advance load conditions corresponding to various types of material tests, and use a value based on the user's selection as a load condition. May be provided.

  The test control unit 20 controls the material test of the composite material. The test control unit 20 receives the load condition from the load condition providing unit 10 and controls the test apparatus 2 based on the load condition. The test control unit 20 receives test data (for example, load or displacement) of the composite material from the test apparatus 2 and calculates a material constant (for example, elastic modulus) of the composite material. The test control unit 20 outputs the obtained material constant of the composite material to the error determination unit 50 as a test result.

  The material constant providing unit 30 sets information on each material included in the composite material and provides the information to the stress analysis unit 40. The material constant providing unit 30 includes a known material providing unit 31 and an unknown material providing unit 32. The known material providing unit 31 provides information on a plurality of known materials whose material constants are known among the plurality of materials included in the composite material to the stress analyzing unit 40 based on the user input. The information on the known material includes the shape of the known material and the material constant. The known material providing unit 31 may provide a value input by the user as information on the known material, or store in advance the shapes and material constants of various types of materials, and set the values based on the selection of the user to the known material. It may be provided as information. In addition, when the known material constant providing unit 31 receives a material constant of a determined unknown material described later from the unknown material providing unit 32, the known material constant providing unit 31 stores the material constant of the known material as a known material constant.

  The unknown material providing unit 32 provides information on one unknown material whose material constant is unknown among the plurality of materials included in the composite material to the stress analyzing unit 40 based on the user input. The information on the unknown material includes the shape of the unknown material and a temporary material constant temporarily set as a predicted value of the material constant of the unknown material. The type of temporary material constant provided by the unknown material providing unit 32 is the same as the type of material constant of the known material provided by the known material providing unit 31. The unknown material providing unit 32 may provide the shape of the unknown material with a value input by the user, or may store various shapes in advance and provide them with values based on the user's selection. Further, the unknown material providing unit 32 may set a value input by the user as a temporary material constant, may set a value stored in advance as a predicted value, or may be a test result of the test control unit 20. Alternatively, it may be set by predicting from the relationship with the material constant of the known material of the known material providing unit 31. For example, the temporary material constant may be set so that the geometric average of the material constant of the known material and the temporary material constant is equal to the test result.

  In addition, when the unknown material providing unit 32 receives a signal indicating that the error is not within the allowable range from the error determining unit 50, the temporary material constant of the already provided unknown material approaches the material constant of the appropriate unknown material. The temporary material constant of a new unknown material is set by changing and provided to the stress analysis unit 40. The unknown material providing unit 32 may set a value input by the user as a temporary material constant of a new unknown material, may be set based on a change width stored in advance, or the error determination unit 50. It may be set based on the error value calculated in (1). For example, if the error value is positive (the stress analysis result is greater than the experimental result), the temporary material constant is decreased at a constant rate, and the error value is negative (the stress analysis result is lower than the experimental result). In the case of (small), the temporary material constant is increased at a constant rate. This is repeated, but the constant ratio value may be set to be gradually reduced. On the other hand, when the unknown material providing unit 32 receives a signal indicating that the error is within the allowable range from the error determining unit 50, the unknown material providing unit 32 sets the set material constant of the unknown material as the determined material constant to the known material providing unit 31. provide.

  The stress analysis unit 40 receives a load condition from the load condition providing unit 10 and further receives information on each material included in the composite material from the material constant providing unit 30. The stress analysis unit 40 performs stress analysis on the model of the composite material based on the load condition and information on each material included in the composite material. The stress analysis unit 40 calculates a material constant (for example, elastic modulus) of the model of the composite material based on the obtained data (for example, load or displacement). The stress analysis unit 40 calculates the material constant using numerical analysis such as finite element method analysis or mathematical expression processing technology such as analytical solution. The stress analysis unit 40 outputs the obtained material constant of the model of the composite material as an analysis result to the error determination unit 50.

  The error determination unit 50 has an allowable range corresponding to the test as a reference value for error determination input by the user. The error determination unit 50 receives the test result from the test control unit 20 and receives the analysis result from the stress analysis unit 40. The error determination unit 50 compares the test result and the analysis result, and determines whether or not the error between the two results is within an allowable range. Note that the error determination unit 50 may compare, for example, only the elastic deformation region or only the vicinity of the glass transition point according to the characteristics of the composite material. In that case, the error determination unit 50 acquires a range of values to be compared based on a user input. Further, the error determination unit 50 may determine the entire range of the load condition using a least square error, and may further determine using a weighted least square method or a nonlinear least square method. When the error is within the allowable range, the error determination unit 50 determines the temporary material constant temporarily set as the predicted value as the material constant of the unknown material. Specifically, the error determination unit 50 outputs a signal indicating that the error is within an allowable range to the unknown material providing unit 32, and the unknown material providing unit 32 supplies the set material constant of the unknown material to the known material providing unit 31. provide. On the other hand, when the error is not within the allowable range, the error determination unit 50 outputs a signal indicating that the error is not within the allowable range to the unknown material providing unit 32. If the error is not within the allowable range, the unknown material providing unit 32 continues to change the temporary material constant of the unknown material until the error falls within the allowable range. The error determination unit 50 outputs the test result, the analysis result, the determination result, and the determined material constant of the unknown material to the output unit 60.

  The output unit 60 outputs the information received from the error determination unit 50 so that the user can recognize it.

  The estimation device 3 of the material constant estimation system 1 according to the embodiment of the present invention can be realized using a computer. FIG. 2 is a block diagram illustrating a hardware configuration example in the embodiment of the estimation device 3. Referring to FIG. 2, the estimation device 3 of the present invention is a computer system including a CPU (Central Processing Unit) 70, a storage device 71, an input device 72, an output device 73, and a bus 74 that connects the devices. Consists of.

  The CPU 70 performs arithmetic processing and control processing according to the material constant estimation system 1 of the present invention stored in the storage device 71. The storage device 71 is a device that records information, such as a hard disk or a memory. The storage device 71 stores a program read from a computer-readable storage medium such as a CD-ROM or DVD, a signal or program input from the input device 72, and a processing result of the CPU 70. The input device 72 is a device that allows a user to input commands and signals, such as a mouse, a keyboard, and a microphone. The output device 73 is a device that causes the user to recognize the output result, such as a display or a speaker. In addition, this invention is not limited to what was shown as a hardware structural example, Each part can be implement | achieved independently or combining hardware and software.

  FIG. 3 is a flowchart showing the processing operation of the material constant estimation system 1 according to the embodiment of the present invention. With reference to FIG. 3, the processing operation according to the embodiment of the present invention will be described.

Step S01:
The load condition providing unit 10 provides a load condition of a material test to be performed on the composite material to the test control unit 20 and the stress analysis unit 40 based on a user input. The load condition providing unit 10 may provide a value input by the user as a load condition, store in advance load conditions corresponding to various types of material tests, and use a value based on the user's selection as a load condition. May be provided.

Step S02:
The test control unit 20 receives the load condition from the load condition providing unit 10 and controls the test apparatus 2 based on the load condition. The test apparatus 2 performs a material test on the composite material based on the control of the estimation apparatus 3, and measures test data (for example, load and displacement) related to physical properties for calculating the material constant of the composite material. The test apparatus 2 outputs the measured test data to the estimation apparatus 3. The test control unit 20 receives test data from the test apparatus 2 and calculates a material constant (for example, elastic modulus) of the composite material. The test control unit 20 outputs the obtained material constant of the composite material to the error determination unit 50 as a test result.

Step S03:
The known material providing unit 31 provides information on a plurality of known materials whose material constants are known among the plurality of materials included in the composite material to the stress analyzing unit 40 based on the user input. The information on the known material includes the shape of the known material and the material constant. The known material providing unit 31 may provide a value input by the user as information on the known material, or store in advance the shapes and material constants of various types of materials, and set the values based on the selection of the user to the known material. It may be provided as information.

Step S04:
The unknown material providing unit 32 provides information on one unknown material whose material constant is unknown among the plurality of materials included in the composite material to the stress analyzing unit 40 based on the user input. The information on the unknown material includes the shape of the unknown material and a temporary material constant temporarily set as a predicted value of the material constant of the unknown material. The type of temporary material constant provided by the unknown material providing unit 32 is the same as the type of material constant of the known material provided by the known material providing unit 31. The unknown material providing unit 32 may provide the shape of the unknown material with a value input by the user, or may store various shapes in advance and provide them with values based on the user's selection. Further, the unknown material providing unit 32 may set a value input by the user as a temporary material constant, may set a value stored in advance as a predicted value, or may be a test result of the test control unit 20. Alternatively, it may be set by predicting from the relationship with the material constant of the known material of the known material providing unit 31.

Step S05:
The stress analysis unit 40 receives a load condition from the load condition providing unit 10 and further receives information on each material included in the composite material from the material constant providing unit 30. The stress analysis unit 40 performs stress analysis on the model of the composite material based on the load condition and information on each material included in the composite material. The stress analysis unit 40 calculates a material constant (for example, elastic modulus) of the model of the composite material based on the obtained data (for example, load or displacement). The stress analysis unit 40 outputs the obtained material constant of the model of the composite material as an analysis result to the error determination unit 50.

Step S06:
The error determination unit 50 has an allowable range as a reference value for error determination. The error determination unit 50 receives the test result from the test control unit 20 and receives the analysis result from the stress analysis unit 40. The error determination unit 50 compares the test result and the analysis result, and determines whether or not the error between the two results is within an allowable range.

Step S07:
In step S06, when the error determination unit 50 determines that the error is not within the allowable range (NO), the error determination unit 50 outputs a signal indicating that the error is not within the allowable range to the unknown material providing unit 32. The output unit 60 outputs the information received from the error determination unit 50 so that the user can recognize it. Thereafter, the process returns to step S04, and the unknown material providing unit 32 changes the temporary material constant of the unknown material that has already been provided, based on the signal indicating that the error is not within the allowable range, and creates a new temporary material of the unknown material. A constant is set and provided to the stress analysis unit 40. At this time, the unknown material providing unit 32 may set a value input by the user as a temporary material constant of a new unknown material, or may set based on a change width stored in advance, The error may be set based on the error value calculated by the error determination unit 50.

Step S08:
In step S06, when the error is within the allowable range (YES), the error determination unit 50 determines the temporary material constant temporarily set as the predicted value as the material constant of the unknown material. Specifically, the error determination unit 50 outputs a signal indicating that the error is within an allowable range to the unknown material providing unit 32. The unknown material providing unit 32 provides the set material constant of the unknown material to the known material providing unit 31. The known material constant providing unit 31 stores the determined material constant of the unknown material as the material constant of the known material. The output unit 60 outputs the information received from the error determination unit 50 so that the user can recognize it.

  As described above, the material constant estimation system 1 of the present invention gives a temporary material constant to an unknown material included in a composite material, and determines whether or not the temporary material constant is suitable. And an appropriate material constant can be estimated by making a determination based on the error between the two results of the analysis result of the composite material model. Thereby, the material constant estimation system 1 of the present invention has an effect that an appropriate material constant can be determined even for a material that is difficult to cut out from a composite material and perform a material test. In addition, the test results include the effect of energy loss such as slip and heat loss at the material interface of the composite material. Therefore, the material constant estimation system 1 of the present invention can determine an unknown material constant in consideration of the energy loss at the material interface by using the test result including the energy loss. There is an effect that the strain can be obtained more accurately.

(Second Embodiment)
A second embodiment of the present invention will be described. The material constant estimation system of the present invention can determine one material constant for an unknown material at a time. Therefore, in the first embodiment, the composite material includes a plurality of known materials and one unknown material. In the second embodiment of the present invention, a case where the composite material includes a plurality of unknown materials will be described. Since the material estimation system according to the second embodiment of the present invention has the same configuration as that of the first embodiment, it will be described below using the same reference numerals as those in FIG.

  When the material constants of the two materials are unknown, the material constant estimation system 1 according to the second embodiment of the present invention first analyzes a composite material including a plurality of known materials and one unknown material, The material constant of the first unknown material is determined. Thereafter, the material constant estimation system 1 analyzes the composite material including all the known materials including the determined material constant and the other unknown material, and determines the material constant of the second unknown material. Therefore, the material constant estimation system 1 of the second embodiment determines the material constant of the first unknown material by the processing operation of the first embodiment shown in FIG. The process of determining the material constant of the unknown material is performed. When three or more unknown materials are included, this process is repeated.

  FIG. 4 is a flowchart showing the processing operation of the material constant estimation system 1 according to the second embodiment of the present invention. A processing operation according to the second embodiment of the present invention will be described with reference to FIG. FIG. 4 shows a processing operation for determining the material constant of the second unknown material after the material constant of the first unknown material is determined by the processing operation shown in FIG.

Step S11:
The load condition providing unit 10 provides the load condition of the material test to be performed on the composite material to the test control unit 20 and the stress analysis unit 40 under the same conditions as the user input or the previous time.

Step S12:
The test control unit 20 receives the load condition from the load condition providing unit 10 and controls the test apparatus 2 based on the load condition. The test apparatus 2 performs a material test on the composite material based on the control of the estimation apparatus 3, and measures test data (for example, load and displacement) related to physical properties for calculating the material constant of the composite material. Here, the test apparatus 2 executes the material test on the composite material including the unknown material whose material constant is determined in the first embodiment as the known material and one other unknown material. The test apparatus 2 outputs the measured test data to the estimation apparatus 3. The test control unit 20 receives test data from the test apparatus 2 and calculates a material constant (for example, elastic modulus) of the composite material. The test control unit 20 outputs the obtained material constant of the composite material to the error determination unit 50 as a test result.

Step S13:
The known material providing unit 31 provides information on a plurality of known materials whose material constants are known among the plurality of materials included in the composite material to the stress analyzing unit 40 based on the user input. The information on the known material includes the shape of the known material and the material constant. Here, the known material providing unit 31 sets the material constant of one unknown material determined in the first embodiment as information on the known material.

  Steps S14 to S18 are the same as steps S04 to S08 in FIG.

  As described above, in the material constant estimation system 1 according to the second embodiment of the present invention, the material constant of at least one material is known even when the composite material is composed of a large number of materials. For example, by determining the material constants of unknown materials one by one, all the material constants constituting the composite material can be determined.

Example 1
The material constant estimation system 1 according to the embodiment of the present invention will be described using a specific example. FIG. 5 is a schematic diagram of a cross section of the composite material 100. Referring to FIG. 5, the composite material 100 is a glass / epoxy resin composite material in which an e-glass 110 of glass fiber is impregnated with an epoxy resin 120. The e-glass 110 is generally used, and the elastic modulus and Poisson's ratio are known from catalog values and the like. On the other hand, the mechanical properties of the epoxy resin 120 vary depending on molding conditions and curing conditions. Moreover, even if it cuts out from the composite material 100 and measures mechanical characteristics, the epoxy resin 120 cannot often obtain the quantity required for a test. That is, the epoxy resin 120 is a material whose material constant is unknown.

The load condition providing unit 10 provided the test control unit 20 with the load condition set as the strain rate of 10 ⁻³ (1 / s) in the longitudinal uniaxial tensile test at room temperature.

  FIG. 6 is a schematic diagram of the results of a tensile test performed on the composite material 100. Referring to FIG. 6, the slope of the elastic range of the obtained stress-strain curve (the elastic modulus of the composite material 100) was smaller than the elastic modulus of the e-glass 110.

  The known material providing unit 32 provided the stress analysis unit 40 with the shape of the e-glass 110 and the material constant set as the elastic modulus of 70 [GPa] and the Poisson's ratio of 0.3. The unknown material providing unit 32 provides the stress analysis unit 40 with the shape of the epoxy resin 120 and a temporary material constant having a reduced elastic modulus or the like as the material constant. At that time, as the elastic modulus, 35 [GPa], which is 50% of the elastic modulus of the e-glass 110, was set as a temporary material constant.

FIG. 7 shows the composite material 100 shown by the finite element method analysis model. Referring to FIG. 7, the model of the composite material 100 includes an e-glass 110 and an epoxy resin 120. In consideration of a certain amount of deviation, the interface between the e-glass 110 and the epoxy resin 120 is dealt with partially mismatched portions of the element division of the interface by internal multipoint constraint. The stress analysis unit 40 performs stress analysis on the model of the composite material 100, and obtains a stress-strain curve from the relationship between the load and displacement generated in the model of the composite material 100. The stress analysis was an elasto-plastic creep analysis, the plasticity was considered using the two linear approximate kinematic hardening law, and the viscosity was considered using the Norton law. As in the material test, the load condition is that one end is fixed and the other end is pulled at a strain rate of 10 ⁻³ (1 / s).

  FIG. 8 is a schematic diagram of a stress-strain curve obtained by stress analysis of a tensile test performed on a model of the composite material 100. The error determination unit 50 has an allowable range that “the determination coefficient R2 of the least square error of the elastic deformation range is 0.95 or more” as a reference value for error determination. The error determination unit 50 compares the test result with the analysis result, and when the determination coefficient R2 of the least square error of stress and strain in the elastic deformation range is 0.95 or less, the material constant (elastic modulus) given to the epoxy resin 120 , Poisson's ratio, yield stress, plasticity coefficient, viscosity constant) were sequentially changed. In particular, the elastic modulus of the epoxy resin 120 having the greatest influence this time was changed regularly. That is, as a result of analysis with a provisional material constant of 35 [GPa], the stress in the elastic deformation range was lower than the test result. 52.5 [GPa], which is an arithmetic average of 100%, was set as a temporary material constant. Since the stress analysis result was higher than the test result, 62.5% of the elastic modulus of the e-glass 110 (75% and 50% arithmetic average given) was set as a temporary material constant. This was repeated until the error between the test result and the analysis result was within the allowable range.

  FIG. 9 is a schematic diagram illustrating a result in which an error between a test result and an analysis result is within an allowable range when the material constant is a certain value. The error determination unit 50 determines the material constant at this time as the material constant of the epoxy resin 120. The stress analysis unit 40 can obtain the stress / strain distribution of the composite material 100 from the result of the stress analysis using the shapes of the e-glass 110 and the epoxy resin 120 and the material constants. Further, the stress analysis unit 40 can obtain the equivalent elastic modulus when the composite material 100 is regarded as a homogeneous material from the load with respect to the tensile displacement amount.

(Example 2)
Furthermore, the material constant estimation system 1 according to the embodiment of the present invention will be described using another specific example. FIG. 10 is a schematic cross-sectional view of a circuit board 500 that is a glass / epoxy resin composite material. Referring to FIG. 10, the circuit board 500 includes a member 300 and a core material 400. The circuit board 500 has a structure in which the core material 400 is sandwiched between the members 300. First, the analysis of the member 300 will be described.

The load condition providing unit 10 provided the test controller 20 with a load condition set so that the strain rate of the circuit board surface was 10 ⁻⁴ (1 / s) in the three-point bending test at room temperature.

  In the member 300, the copper wiring 130 and the solder resist 140 are combined with the composite material 100. First, the material constant estimation system 1 was processed in the same manner as in the first embodiment for the composite material 200 in which the copper wiring 130 was combined with the composite material 100.

  The known material providing unit 32 provided the shape of the e-glass 110 and the epoxy resin 120 and the material constants to the stress analysis unit 40. The material constant of the epoxy resin 120 is the value determined in Example 1. The unknown material providing unit 32 provides the stress analysis unit 40 with the shape of the copper wiring 130 and a temporary material constant having a reduced elastic modulus or the like as the material constant of the copper wiring 130.

The stress analysis unit 40 performs stress analysis of the composite material 200 and obtains a stress-strain curve from the relationship between the load and displacement generated in the composite material 200. The stress analysis was an elasto-plastic analysis, and the plasticity was taken into account using the multi-line isotropic hardening rule. The load condition is a three-point bending test in which the strain rate on the circuit board surface is 10 ⁻⁴ (1 / s), as in the material test. The stress analysis unit 40 obtained a stress-strain curve of the composite material 200.

  The error determination unit 50 compares the test result and the analysis result. If the error is not within the allowable range, the material constant (elastic modulus, Poisson's ratio, yield stress, plastic coefficient) given to the copper wiring 130 is made regular. It was changed sequentially. The error determination unit 50 obtains a result that the error between the test result and the analysis result falls within the allowable range when the material constant is a certain value. The error determination unit 50 determines the material constant at this time as the material constant of the copper wiring 130. The stress analysis unit 40 obtained the equivalent elastic modulus of the composite material 200.

  Thereafter, the material constant estimation system 1 similarly performed the processing of the present invention on the member 300, and obtained the material constant of the solder resist 140 and the equivalent elastic modulus of the member 300.

  Next, analysis of the core material 400 will be described. The core material 400 is a glass cloth composite material in which a glass cloth 410 is impregnated with a resin 420. The glass cloth 410 has known material constants (elastic modulus, Poisson's ratio) from catalog values and the like, but the impregnated resin 420 has unknown material constants. The material constant estimation system 1 analyzed the core material 400 similarly to the member 300, and obtained the material constant of the resin 420 and the equivalent elastic modulus of the core material 400.

  Finally, the material constant estimation system 1 executes the stress analysis of the circuit board 500 based on the shape of the member 300 and the core material 400, the material constant, and the equivalent elastic modulus, thereby obtaining the material constant of the circuit board 500. Can be obtained.

  While the present invention has been described with reference to the embodiments (and examples), the present invention is not limited to the above embodiments (and examples). Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

  This application claims priority based on Japanese Patent Application No. 2010-045352 filed on Mar. 2, 2010 and Japanese Patent Application No. 2010-172994 filed on Jul. 30, 2010. , The entire disclosure of which is incorporated herein.

Claims (13)

A load condition providing unit for providing a load condition of a material test, which is performed on a composite material including the first material and the second material;
A test control unit for controlling a test of the composite material based on the load condition and outputting a test result;
A material constant providing unit that provides a first temporary material constant temporarily set as a first material constant representing an unknown physical property of the first material and a second material constant representing a known physical property of the second material When,
A stress analysis unit that executes a stress analysis on the model of the composite material based on the load condition, the first temporary material constant, and the second material constant, and outputs an analysis result;
An error determination unit for determining whether an error between the test result and the analysis result is within a preset allowable range;
The error determination unit determines the first temporary material constant as the first material constant when the error is within the allowable range. The material constant estimation system according to claim 1,
When the error is not within the allowable range, the error determination unit outputs a signal indicating that the error is not within the allowable range to the material constant providing unit,
The material constant providing unit changes the first temporary material constant to a second temporary material constant based on a signal indicating that the error is not within the allowable range. The material constant estimation system according to claim 2,
The material constant providing unit sets the second temporary material constant by decreasing the first temporary material constant at a constant rate when the analysis result is larger than the test result, and the analysis result is A material constant estimation system that sets the second temporary material constant by increasing the first temporary material constant at a constant rate when the test result is smaller than the test result. Providing a first loading condition of material testing performed on a first composite material comprising a first material and a second material;
Controlling a first test of the first composite material based on the first load condition;
Providing a first temporary material constant provisionally set as a first material constant representing an unknown physical property of the first material and a second material constant representing a known physical property of the second material;
Performing a first stress analysis on a model of the first composite material based on the first load condition, the first temporary material constant, and the second material constant;
Determining whether a first error between the test result of the first test and the first analysis result of the first stress analysis is within a preset allowable range corresponding to the first test; ,
And determining the first temporary material constant as the first material constant when the first error is within an allowable range corresponding to the first test. The material constant estimation method according to claim 4,
When the first error is not within an allowable range corresponding to the first test, changing the first temporary material constant set as the first material constant to the second temporary material constant;
Performing a second stress analysis on the model of the first composite material based on the first load condition, the second temporary material constant, and the second material constant;
Determining whether a second error between the test result of the first test and the second analysis result of the second stress analysis is within an allowable range corresponding to the first test;
And determining the second temporary material constant as the first material constant when the second error is within an allowable range corresponding to the first test. The material constant estimation method according to claim 5,
The step of changing to the second temporary material constant is:
If the analysis result is greater than the test result, reducing the first temporary material constant at a constant rate to set the second temporary material constant;
A method of estimating a material constant, comprising: setting the second temporary material constant by increasing the first temporary material constant at a constant rate when the analysis result is smaller than the test result. The material constant estimation method according to any one of claims 4 to 6,
Providing a second loading condition for material testing performed on a second composite material comprising the first material, the second material, and a third material;
Controlling a second test of the second composite material based on the second load condition;
A third temporary material constant temporarily set as a third material constant representing an unknown physical property of the third material, the first material constant of the first material, and the second material constant of the second material. Providing steps, and
Performing a third stress analysis on the model of the second composite material based on the second load condition, the third temporary material constant, the first material constant, and the second material constant;
Determining whether a third error between the test result of the second test and the third analysis result of the third stress analysis is within an allowable range corresponding to the second test set in advance; ,
And determining a third temporary material constant as the third material constant when the third error is within an allowable range corresponding to the second test. The material constant estimation method according to claim 7,
When the third error is not within an allowable range corresponding to the second test, changing the third temporary material constant set as the third material constant to the fourth temporary material constant;
Performing a fourth stress analysis on the model of the second composite material based on the second load condition, the fourth temporary material constant, the first material constant, and the second material constant;
Determining whether a fourth error between the test result of the second test and the fourth analysis result of the fourth stress analysis is within an allowable range corresponding to the second test;
A step of determining the fourth temporary material constant as the third material constant when the fourth error is within an allowable range corresponding to the second test; Providing a first loading condition of material testing performed on a first composite material comprising a first material and a second material;
Controlling a first test of the first composite material based on the first load condition;
Providing a first temporary material constant provisionally set as a first material constant representing an unknown physical property of the first material and a second material constant representing a known physical property of the second material;
Performing a first stress analysis on a model of the first composite material based on the first load condition, the first temporary material constant, and the second material constant;
Determining whether a first error between the test result of the first test and the first analysis result of the first stress analysis is within a preset allowable range corresponding to the first test; ,
When the first error is within an allowable range corresponding to the first test, a program for realizing a material constant estimation method including the step of determining the first temporary material constant as the first material constant is recorded. A computer-readable recording medium. The recording medium according to claim 9, wherein
The material constant estimation method is:
When the first error is not within an allowable range corresponding to the first test, changing the first temporary material constant set as the first material constant to the second temporary material constant;
Performing a second stress analysis on the model of the first composite material based on the first load condition, the second temporary material constant, and the second material constant;
Determining whether a second error between the test result of the first test and the second analysis result of the second stress analysis is within an allowable range corresponding to the first test;
And a step of determining the second temporary material constant as the first material constant when the second error is within an allowable range corresponding to the first test. The recording medium according to claim 10,
The step of changing to the second temporary material constant is:
If the analysis result is greater than the test result, reducing the first temporary material constant at a constant rate to set the second temporary material constant;
A step of setting the second temporary material constant by increasing the first temporary material constant at a constant rate when the analysis result is smaller than the test result; The recording medium according to claim 9 to 11,
The material constant estimation method is:
Providing a second loading condition for material testing performed on a second composite material comprising the first material, the second material, and a third material;
Controlling a second test of the second composite material based on the second load condition;
A third temporary material constant temporarily set as a third material constant representing an unknown physical property of the third material, the first material constant of the first material, and the second material constant of the second material. Providing steps, and
Performing a third stress analysis on the model of the second composite material based on the second load condition, the third temporary material constant, the first material constant, and the second material constant;
Determining whether a third error between the test result of the second test and the third analysis result of the third stress analysis is within an allowable range corresponding to the second test set in advance; ,
And a step of determining the third temporary material constant as the third material constant when the third error is within an allowable range corresponding to the second test. The recording medium according to claim 12,
The material constant estimation method is:
When the third error is not within an allowable range corresponding to the second test, changing the third temporary material constant set as the third material constant to the fourth temporary material constant;
Performing a fourth stress analysis on the model of the second composite material based on the second load condition, the fourth temporary material constant, the first material constant, and the second material constant;
Determining whether a fourth error between the test result of the second test and the fourth analysis result of the fourth stress analysis is within an allowable range corresponding to the second test;
And a step of determining the fourth temporary material constant as the third material constant when the fourth error is within an allowable range corresponding to the second test.

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