JP2010197150A - Device and method for evaluating damage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve evaluation of the presence/absence of damage occurred under any condition without repeating experiments using an actual metal member. <P>SOLUTION: By performing non-steady heat conduction analysis and plasticity analysis using a finite element method on a structure for friction pressure contact based on structure data, temperature data, material data, and analysis conditions, a temperature and stress of each element at each lapse time are calculated. Whether the stress of each element at each lapse time calculated by FEM analysis is larger than a tensile strength corresponding to the temperature of the element at the lapse time is determined. When the stress is larger than the tensile strength, it is evaluated that damage will occur in the element. When the stress is smaller than the tensile strength, it is evaluated that damage will not occur in the element. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a damage evaluation apparatus and a damage evaluation method for evaluating whether or not a structure is damaged, in particular, whether or not a structure subjected to friction welding is damaged in the subsequent process.

  2. Description of the Related Art Conventionally, friction welding is used as a method for joining a metal member and a metal member in the manufacture of an aircraft engine shaft or the like. Friction welding is a kind of welding method for joining metal members to each other by frictional heat, and has an advantage that different metals and non-ferrous metals can be joined.

  In the friction welding, since the joining surfaces of the metal members to be joined are rotated to generate frictional heat due to the frictional force, the vicinity of the joining surface becomes very high. The strength of the metal decreases as the temperature increases. In the friction welding, since the metal members to be joined are pressed against each other by pressing, a pressing stress is generated in the vicinity of the joining surface. Therefore, as a result of the strength being lowered at a high temperature, damage such as cracking may occur in the metal member due to the pressing stress.

  Conventionally, in order to investigate friction welding parameters (rotation speed, pressing force, surface condition of joint surface, etc.) that do not cause such damage, experiments using actual metal members were repeatedly performed with various parameters. Was looking for parameters that would not cause damage.

  In addition, the analysis simulation technique about structures, such as an aircraft engine mentioned above, is proposed conventionally. For example, a technique for simulating the impact load of a shaft of an aero engine or the like (see Patent Document 1), or a technique for simulating the leakage of dissolved metal that occurs on the joint surface of friction welding (see Non-Patent Document 1) ) Has been proposed.

JP 2004-322816 A

Machine Design International, 2005, Vol.77, No.1, pp68-70

  High-strength, high-cost metals have been used for members such as shafts joined by friction welding in accordance with recent demands for weight reduction. Therefore, if the experiment using an actual metal is repeatedly performed to determine the friction welding parameters, the cost increases.

  In view of the above circumstances, the present invention provides a damage evaluation apparatus and a damage evaluation method capable of evaluating the presence or absence of damage occurrence under arbitrary conditions without repeatedly performing experiments using actual metal members. The purpose is to do.

  [1] In order to solve the above-described problem, a damage evaluation apparatus according to an aspect of the present invention includes a structure data storage unit that stores structure data of a structure to be evaluated by friction welding, and a temperature distribution of the structure. And a temperature data storage unit that stores temperature data including a temperature distribution related to frictional heat generated by friction welding of the structure, and a material data storage unit that stores material data related to the material of the structure; An analysis condition storage unit that stores analysis conditions for performing the evaluation, a strength data storage unit that stores the correspondence between the temperature and tensile strength of the material of the structure, and the structure data storage unit The structure data, the temperature data stored in the temperature data storage unit, the material data stored in the material data storage unit, and stored in the analysis condition storage unit FEM analysis unit for calculating temperature and stress in each element at each elapsed time by performing unsteady heat conduction analysis and elastoplastic analysis using a finite element method on the structure based on the analysis conditions And whether the stress calculated by the FEM analysis unit for each element of each elapsed time is greater than the tensile strength stored in the strength data storage unit in association with the temperature of the element for the elapsed time An evaluation that evaluates that the element is damaged if the stress is greater than the tensile strength, and evaluates that the element is not damaged if the stress is less than the tensile strength. And an output unit that outputs an evaluation result in the evaluation unit.

  [2] In the damage evaluation apparatus according to one aspect of the present invention described above, the structure to be evaluated is a structure that is friction-welded by rotational friction, and the frictional heat in the temperature data is the structure It is friction heat at the time when the rotation of the object stops, and the FEM analysis unit performs the unsteady heat conduction analysis after the time when the rotation of the structure stops. good.

  [3] A damage evaluation method according to an aspect of the present invention includes a structure data storage unit that stores structure data of a structure to be evaluated, and a temperature data storage that stores temperature data representing a temperature distribution of the structure. A material data storage unit that stores material data relating to the material of the structure, an analysis condition storage unit that stores analysis conditions for performing the evaluation, and a temperature and a tensile strength of the material of the structure A damage evaluation apparatus having a strength data storage unit for storing a correspondence relationship, the structural data stored in the structural data storage unit, the temperature data stored in the temperature data storage unit, and the material data storage Based on the material data stored in the section and the analysis conditions stored in the analysis condition storage section, the structure is subjected to unsteady heat conduction analysis and elastoplastic using a finite element method. FEM analysis step for calculating temperature and stress in each element at each elapsed time by performing analysis, and the damage evaluation apparatus calculates the stress calculated by the FEM analysis step for each element at each elapsed time, It is determined whether the tensile strength is greater than the tensile strength stored in the strength data storage unit in association with the temperature of the element during the elapsed time. If the stress is greater than the tensile strength, the element is damaged. An evaluation step of evaluating that the damage is not caused in the element when the stress is smaller than the tensile strength, and an output step of outputting the evaluation result in the evaluation unit, Is provided.

  According to the present invention, it is possible to evaluate the presence / absence of occurrence of damage under arbitrary conditions without repeatedly performing experiments using actual metal members. In addition, it is possible to evaluate whether or not damage occurs after joining due to frictional heat stress generated by friction welding without repeatedly performing experiments.

It is a schematic block diagram showing the function structure of a damage evaluation apparatus. It is a figure showing the specific example of the structure used as the object of evaluation which a damage evaluation apparatus performs. It is a figure showing the specific example of the temperature data input by the temperature data input part. It is a figure showing the specific example of the temperature data input by the temperature data input part. It is a figure showing the specific example of the temperature data input by the temperature data input part. It is a figure showing material data for heat conduction analysis among material data inputted by a material data input part. It is a figure showing the material constant data for elastic-plastic analysis among the material data input by a material data input part. It is a figure showing the plastic strain data for elastic-plastic analysis among the material data input by the material data input part. It is a figure showing the mesh structure used when a FEM analysis part divides | segments an evaluation object structure into a some element when applying a finite element method. It is a figure showing the specific example of the intensity | strength data input by an intensity | strength data input part. It is a figure showing the specific example of the evaluation which an evaluation part performs based on intensity | strength data. It is a flowchart showing operation | movement of a damage evaluation apparatus.

  FIG. 1 is a schematic block diagram showing a functional configuration of the damage evaluation apparatus 1. As shown in the figure, the damage evaluation apparatus 1 includes a structure data input unit 101, a structure data storage unit 102, a temperature data input unit 103, a temperature data storage unit 104, a material data input unit 105, a material data storage unit 106, and an analysis condition input. Unit 107, analysis condition storage unit 108, FEM analysis unit 109, intensity data input unit 110, intensity data storage unit 111, evaluation unit 112, and output unit 113. Hereinafter, each functional unit included in the damage evaluation apparatus 1 will be described.

  The structure data input unit 101 inputs structure data of a structure that is symmetrical to the evaluation performed by the damage evaluation apparatus 1. The structure data is created using CAD (Computer Aided Design) software such as AutoCAD (registered trademark), CADAM (registered trademark), and Jw_cad. The structure data created using the CAD software in this way is configured by a file format such as DXF (Drawing Interchange File), DWG, or SXF (Scadec data eXchange Format).

  The structure data storage unit 102 is configured using a storage device such as a magnetic hard disk or a semiconductor storage device, and stores the structure data input by the structure data input unit 101. The structural data stored in the structural data storage unit 102 is stored in the FEM analysis unit 109 when the FEM analysis unit 109 performs unsteady heat conduction analysis and elastoplastic analysis (stress analysis) by a finite element method (FEM). Read by.

  The temperature data input unit 103 inputs temperature data of a structure to be evaluated by the damage evaluation apparatus 1. The temperature data is data representing the temperature distribution in the initial state of the structure to be evaluated. The initial state is a state at the time when unsteady heat conduction analysis and elasto-plastic analysis are started. For example, in the case of damage evaluation in friction welding by rotational friction, it represents a state at the time when rotation is stopped. The point at which the rotation stops is the point at which the relative rotation speed of the other structure with respect to the one structure becomes zero. That is, the temperature data represents a temperature distribution of the structure, and includes at least a temperature distribution related to frictional heat generated by friction welding the structure.

  The temperature data storage unit 104 is configured using a storage device such as a magnetic hard disk or a semiconductor storage device, and stores the temperature data input by the temperature data input unit 103. The temperature data stored in the temperature data storage unit 104 is read out by the FEM analysis unit 109 when the FEM analysis unit 109 performs an unsteady heat conduction analysis by a finite element method.

  The material data input unit 105 inputs material data of a structure to be evaluated by the damage evaluation apparatus 1. Material data is data representing the material properties of the structure to be evaluated. Details of the material data will be described later.

  The material data storage unit 106 is configured using a storage device such as a magnetic hard disk or a semiconductor storage device, and stores the material data input by the material data input unit 105. The material data stored in the material data storage unit 106 is read out by the FEM analysis unit 109 when the FEM analysis unit 109 performs unsteady heat conduction analysis and elastoplastic analysis by the finite element method.

  The analysis condition input unit 107 inputs all analysis conditions necessary for performing the unsteady heat conduction analysis and the elasto-plastic analysis in the FEM analysis unit 109. The analysis conditions include, for example, restraint conditions and load conditions (internal pressure, reaction force, etc.) related to a structure to be subjected to unsteady heat conduction analysis and elastic-plastic analysis.

  The analysis condition storage unit 108 is configured using a storage device such as a magnetic hard disk or a semiconductor storage device, and stores the analysis conditions input by the analysis condition input unit 107. The analysis conditions stored in the analysis condition storage unit 108 are read out by the FEM analysis unit 109 when the FEM analysis unit 109 performs unsteady heat conduction analysis and elastoplastic analysis by the finite element method.

  The FEM analysis unit 109 includes structural data stored in the structural data storage unit 102, temperature data stored in the temperature data storage unit 104, material data stored in the material data storage unit 106, and an analysis condition storage unit 108. The unsteady heat conduction analysis using the finite element method is performed based on the analysis conditions stored in the table, and the temperature at each element of each elapsed time (elapsed time from the initial state) of the structure to be evaluated is calculated. .

  Furthermore, the FEM analysis unit 109 stores the structure data stored in the structure data storage unit 102, the analysis result of the unsteady heat conduction analysis, the material data stored in the material data storage unit 106, and the analysis condition storage unit 108. Based on the stored analysis conditions, an elasto-plastic analysis using the finite element method is performed, and the stress generated in each element of each elapsed time (elapsed time from the initial state) of the structure to be evaluated is calculated.

  The strength data input unit 110 inputs strength data representing the correspondence between the temperature and tensile strength of the material of the structure to be evaluated. The tensile strength represents a maximum stress generated in the material in the tensile test, and is a value that varies depending on the temperature of the material. Damage occurs if a stress greater than the tensile strength occurs on the material.

  The intensity data storage unit 111 is configured using a storage device such as a magnetic hard disk or a semiconductor storage device, and stores the intensity data input by the intensity data input unit 110. The intensity data stored in the intensity data storage unit 111 is read by the evaluation unit 112 when the evaluation unit 112 evaluates whether or not damage has occurred, and the evaluation result is output by the output unit 113.

  FIG. 2 is a diagram illustrating a specific example of a structure to be evaluated by the damage evaluation apparatus 1. In the following description, the structure to be evaluated by the damage evaluation apparatus 1 is a cylindrical device structure (hereinafter referred to as “evaluation object”) illustrated in FIG. However, a solid circular device structure can also be an evaluation object. The evaluation object is a cylinder in which a hollow portion of a concentric cylinder with a radius R is provided with respect to a cylinder with a radius (R + W), and the thickness is W. Hereinafter, the distance in the radial direction from the center of the circle of the evaluation object is represented as r. In addition, an angle representing the displacement in the rotational direction when the center of the circle of the evaluation object is used as an axis is represented as θ.

  FIG. 2B shows a state in which the evaluation object is friction-welded in the axial direction about the center of the circle with respect to the same-shaped cylinder. In FIG. 2 (B), a line represented by the boundary between the weld surface friction welded and the side surface of the cylinder is called a weld line, and the distance from the weld line in the axial direction, that is, the distance from the weld surface is represented as x.

  3 to 5 are diagrams illustrating specific examples of temperature data input by the temperature data input unit 103. FIG. 3 is a diagram illustrating a temperature change in the x direction at r = (R + W) when the temperature distribution of the evaluation object is expressed as a binary function of x and r, where t = f (x, r). . In this case, a function of f (x, r) representing t is temperature data. When the temperature data is configured in this way, the temperature distribution of the evaluation object is determined by the binary values of x and r, so the temperature remains constant in the rotation direction (θ direction) with the center of the circle as the axis. It is.

  In FIG. 3, the horizontal axis represents the distance x from the welding surface, and the vertical axis represents the temperature t. t at x = 0 represents the temperature of the weld surface. As shown in FIG. 3, when x is small, t is constant, and thereafter, as x increases, t decreases, and t becomes constant again. The value of t that is constant when x is small represents the melting temperature of the evaluation object, and the value of t when it becomes constant thereafter is the temperature of the evaluation object that is not affected by frictional heat due to friction welding. Indicates.

  FIG. 4 is a diagram showing a temperature change in the r direction at x = 0 when the temperature distribution of the evaluation object is expressed as a binary function of x and r with t = f (x, r). In FIG. 4, the horizontal axis represents the distance r from the center of the circle, and the vertical axis represents the temperature t. Between r = 0 and r = R is a hollow portion, and there is no value of t because there is no metal to be evaluated. Further, when r is larger than r = (R + W), there is no value of t because there is no metal to be evaluated. Between r = R and r = (R + W), there is a value of t because the metal to be evaluated exists, and the value of t increases as the value of r increases.

  FIG. 5 is a diagram illustrating a specific example of temperature data having a value of t in association with a combination of a value of x and a value of r. In the case of FIG. 5, the temperature data is not a function of t = f (x, r), but is configured as a table representing the relationship between the combination of x and r and t. Even when the temperature data is configured in this way, the temperature distribution of the evaluation object is determined by the binary values of x and r, so that the temperature changes in the rotation direction (θ direction) with the center of the circle as the axis. It is constant.

  The temperature data input by the temperature data input unit 103 may be configured as a function of t = f (x, r) as in the case of FIGS. 3 and 4 or represented as a table as in FIG. May be. When the temperature data is configured as shown in FIGS. 3 and 4, the FEM analysis unit 109 calculates the value of t by substituting arbitrary values of x and r into the function. On the other hand, when the temperature data is configured as shown in FIG. 5, the FEM analysis unit 109 searches the table for a combination of x and r that is closest to the values of arbitrary x and r, and associates them with this combination. Read the value of t. At this time, the FEM analysis unit 109 may calculate an approximate value of t corresponding to an arbitrary value of x and r by a method such as linear interpolation.

FIG. 6 is a diagram showing material data used for unsteady heat conduction analysis (hereinafter referred to as “material data for heat conduction analysis”) among the material data inputted by the material data input unit 105. The material data for heat conduction analysis has thermal conductivity, specific heat, and density at a given temperature in association with a plurality of temperatures. FIG. 6 is a diagram illustrating heat conduction analysis material data regarding the material X used for the evaluation object. In FIG. 6, for example, the thermal conductivity when the temperature is 20 degrees Celsius λ ₁ (W / m · degrees Celsius), specific heat _C P1 (J / degrees Celsius · kg), density ρ ₁ (kg / Cubic meters).

FIG. 7 is a diagram illustrating material data representing material constants used for elastic-plastic analysis (hereinafter referred to as “material constant data for elastic-plastic analysis”) among the material data input by the material data input unit 105. The material constant data for elastoplastic analysis has a Young's modulus, Poisson's ratio, and linear expansion coefficient at a given temperature in association with a plurality of temperatures. FIG. 7 is a diagram showing material constant data for elastic-plastic analysis related to the material X used for the evaluation object. In the case of FIG. 7, for example, when the temperature is 200 degrees, the Young's modulus is E ₃ (GPa), the Poisson's ratio is ν ₃ , and the linear expansion coefficient is α ₃ (/ degrees Celsius).

FIG. 8 shows material data (hereinafter referred to as “plastic strain data for elastic-plastic analysis”) that represents the relationship between temperature, plastic strain, and stress, which is used for elastic-plastic analysis, among the material data input by the material data input unit 105. It is a figure showing. Specifically, the plastic strain data for elasto-plastic analysis has a value of a stress generated under the condition in association with a combination of a temperature value and a value representing the plastic strain. In the case of FIG. 8, for example, the stress generated when the temperature is 20 degrees Celsius and the plastic strain is 0.0E + 00 is σ ₁₁ MPa.

  FIG. 9 is a diagram illustrating a mesh structure used when the FEM analysis unit 109 divides the evaluation target structure into a plurality of elements when the finite element method is applied. As shown in the figure, the size of the element increases as the distance from the welding surface (x = 0) increases, and the portion where x is the same value has the same size regardless of the value of r. Note that the mesh structure used by the FEM analysis unit 109 to apply the finite element method is not limited to that shown in FIG. 9, and other mesh structures may be used.

  FIG. 10 is a diagram illustrating a specific example of intensity data input by the intensity data input unit 110. Here, tensile strength is used as a criterion for strength evaluation, but it is recommended to use an appropriate strength criterion for designing. In FIG. 10, the horizontal axis represents temperature, and the vertical axis represents tensile strength stress corresponding to each temperature. In the graph shown in FIG. 10, a region A representing a stress lower than the tensile strength and a region B representing a stress higher than the tensile strength with the line (A) representing the relationship between the temperature and the stress of the tensile strength as a boundary. And can be divided into two areas.

  FIG. 11 is a diagram illustrating a specific example of evaluation performed by the evaluation unit 112 based on intensity data. When the stress P1 generated at a certain temperature T1 exists in the region A, the stress P1 is lower than the stress of the tensile strength at that temperature, and therefore no damage is generated by the stress P1. On the other hand, when the stress P2 generated at a certain temperature T1 is present in the region B, the stress P2 is higher than the stress of the tensile strength at that temperature, and thus the stress P2 causes damage. As described above, the evaluation unit 112 determines whether the stress is smaller than the tensile strength at the temperature based on the temperature and stress generated in each element of each elapsed time calculated by the FEM analysis unit 109. Assess the occurrence of damage accordingly.

  FIG. 12 is a flowchart showing the operation of the damage evaluation apparatus 1. Hereinafter, the operation of the damage evaluation apparatus 1 will be described with reference to FIG. First, the structure data input unit 101 inputs structure data of the evaluation object (step S101). The structure data storage unit 102 stores the structure data input by the structure data input unit 101. Next, the temperature data input unit 103 inputs temperature data of the evaluation object (step S102). The temperature data storage unit 104 stores the temperature data input by the temperature data input unit 103. Next, the material data input unit 105 inputs material data of the evaluation object (step S103). The material data storage unit 106 stores the material data input by the material data input unit 105. Next, the analysis condition input unit 107 inputs analysis condition data (step S104). The analysis condition storage unit 108 stores the analysis conditions input by the analysis condition input unit 107. Next, the intensity data input unit 110 inputs intensity data (step S105). The intensity data storage unit 111 stores the intensity data input by the intensity data input unit 110.

  Next, the FEM analysis unit 109 divides the structural data stored in the structural data storage unit 102 into a plurality of elements, and stores the temperature data stored in the temperature data storage unit 104 and the material data storage unit 106. Based on the heat conduction analysis material data and the analysis conditions stored in the analysis condition storage unit 108, an unsteady heat conduction analysis by the finite element method is executed (step S106). Further, the FEM analysis unit 109 stores the analysis result of the unsteady heat conduction analysis, the material data for elastic-plastic analysis stored in the material data storage unit 106, and the analysis condition storage unit 108 for each element after the division. The elastic-plastic analysis by the finite element method is executed based on the analysis conditions (step S107). The FEM analysis unit 109 calculates the temperature T and the stress P at each elapsed time of each element as the analysis results of the unsteady heat conduction analysis and the elastic-plastic analysis.

  Next, the evaluation unit 112 compares the stress P of each element at each elapsed time with the tensile strength Th at the temperature T generated in the element at this time (step S108). When the stress P is larger than the tensile strength Th (step S109—YES), the evaluation unit 112 evaluates that damage occurs in the element and the elapsed time that are the objects of the comparison process (step S110). On the other hand, when the stress P is equal to or less than the tensile strength Th (step S109—NO), the evaluation unit 112 evaluates that no damage occurs in the element and the elapsed time that are the objects of the comparison process (step S111).

  The evaluation unit 112 repeatedly executes the evaluation process until the evaluations in Step S108 to Step S111 are completed for all elapsed times and elements (Step S112—NO). When the evaluation is completed for all the elapsed times and elements (step S112—YES), the evaluation unit 112 outputs the evaluation result (step S113), and the process of the entire flowchart ends.

  In the damage evaluation apparatus 1 configured in this way, the structure data, the temperature data, the material data, and the analysis conditions are input, so that the FEM analysis unit 109 performs the unsteady heat by the finite element method for the evaluation object. Conduction analysis and elastoplastic analysis are performed, and temperature and stress at each elapsed time are calculated for each element. Then, by inputting the strength data, the evaluation unit 112 corresponds to the stress generated at each elapsed time for each element and the temperature at which the stress is generated based on the analysis result in the FEM analysis unit 109. The tensile strength to be compared is compared, and the presence or absence of occurrence of damage to the evaluation object is evaluated. Therefore, it is possible to evaluate the presence or absence of damage without repeatedly performing experiments using actual metal members.

  In addition, when a structure that is friction welded by rotational friction is an object to be evaluated, temperature data representing the temperature distribution at the time when rotation stops is input, so that the FEM analysis unit 109 can perform the friction welding welding. The generated stress is calculated for each elapsed time from when the rotation stops for each element, and the evaluation unit 112 evaluates whether or not the generated stress causes damage. Therefore, in order to determine parameters such as the number of rotations, pressing force, surface condition of the joint surface, and the temperature of the structure of the part not affected by frictional heat due to friction welding as in the past, experiments with each parameter are repeatedly performed. Therefore, it is possible to select temperature data that does not cause damage. In addition, the temperature distribution at the time of joining is determined by parameters such as the number of rotations, pressing force, surface roughness of the joining surface, and the temperature of the structure that is not affected by frictional heat due to friction welding. It is possible to select each value of the parameter so as to obtain such a temperature distribution based on the temperature data that is not. Therefore, it is possible to select each parameter value that does not cause damage without repeatedly performing the experiment, thereby reducing the cost and time required for the experiment.

<Modification>
The temperature data input by the temperature data input unit 103 is not determined by the binary values x and r as shown in FIG. 5, but may be configured by the three values x, r, and θ. By configuring the temperature data in this way, it is possible to perform unsteady heat conduction analysis more accurately, and it is possible to improve the accuracy of elasto-plastic analysis and damage evaluation performed thereafter.

  The structure data storage unit 102, the temperature data storage unit 104, the material data 106, the analysis condition storage unit 108, and the strength data storage unit 111 may each store data in advance.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Damage evaluation apparatus, 101 ... Structural data input part, 102 ... Structural data storage part, 103 ... Temperature data input part, 104 ... Temperature data storage part, 105 ... Material data input part, 106 ... Material data storage part, 107 ... Analysis condition input unit, 108 ... Analysis condition storage unit, 109 ... FEM analysis unit, 110 ... Strength data input unit, 111 ... Strength data storage unit, 112 ... Evaluation unit

Claims (3)

A structure data storage unit for storing structure data of a structure to be subjected to friction welding to be evaluated;
A temperature data storage unit representing temperature distribution of the structure, and storing temperature data including at least temperature distribution related to frictional heat generated by friction welding of the structure;
A material data storage unit for storing material data related to the material of the structure;
An analysis condition storage unit for storing analysis conditions for performing the evaluation;
A strength data storage unit for storing a correspondence relationship between temperature and tensile strength for the material of the structure;
The structural data stored in the structural data storage unit, the temperature data stored in the temperature data storage unit, the material data stored in the material data storage unit, and stored in the analysis condition storage unit FEM analysis unit for calculating temperature and stress in each element at each elapsed time by performing unsteady heat conduction analysis and elastic-plastic analysis using a finite element method on the structure based on the analysis conditions When,
Whether the stress calculated by the FEM analysis unit for each element of each elapsed time is greater than the tensile strength stored in the strength data storage unit in association with the temperature of the element for the elapsed time An evaluation unit that evaluates and evaluates that the element is damaged when the stress is larger than the tensile strength, and evaluates that the element is not damaged when the stress is smaller than the tensile strength; ,
An output unit for outputting an evaluation result in the evaluation unit;
A damage evaluation apparatus comprising: The structure to be evaluated is a structure that is friction welded by rotational friction,
The frictional heat in the temperature data is the frictional heat at the time when the rotation of the structure stops,
The FEM analysis unit performs the unsteady heat conduction analysis after the time when the rotation of the structure stops.
The damage evaluation apparatus according to claim 1, wherein: A structure data storage unit that stores structure data of a structure to be evaluated, a temperature data storage unit that stores temperature data representing a temperature distribution of the structure, and a material data that stores material data related to the material of the structure Damage evaluation apparatus comprising: a storage unit; an analysis condition storage unit that stores an analysis condition for performing the evaluation; and a strength data storage unit that stores a correspondence relationship between temperature and tensile strength of the material of the structure Are stored in the structural data storage unit, the temperature data stored in the temperature data storage unit, the material data stored in the material data storage unit, and the analysis condition storage unit. Based on the stored analysis conditions, the unsteady heat conduction analysis and elasto-plastic analysis using the finite element method are performed on the structure, so that each element at each elapsed time is analyzed. And FEM analysis step of calculating a that temperature and stress,
The tensile strength stored in the strength data storage unit is the stress calculated by the FEM analysis step for each element of the elapsed time, in association with the temperature of the element of the elapsed time. If the stress is greater than the tensile strength, the element is evaluated as being damaged. If the stress is less than the tensile strength, the element is not damaged. An evaluation step for evaluating
The damage evaluation device outputs an evaluation result in the evaluation unit;
A damage evaluation method comprising:

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