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CN-122024966-A - Method and system suitable for thermal deformation analysis of anisotropic composite structure

CN122024966ACN 122024966 ACN122024966 ACN 122024966ACN-122024966-A

Abstract

The invention provides a method and a system suitable for thermal deformation analysis of an anisotropic composite material structure, which comprise the steps of establishing a structure finite element analysis model, applying boundary constraint and load conditions, setting thermal expansion coefficient properties and material mechanical properties of model materials, initializing thermal expansion coefficient properties and material mechanical property polarities of model materials, carrying out simulation analysis and calculation on internal strain of the structure, checking and correcting thermal constitutive property polarities of each unit according to temperature and load calculation results of each unit of a finite element model, checking and correcting force constitutive property polarities of each unit according to temperature and load calculation results of each unit of the finite element model, judging whether a current strain calculation result meets tolerance requirements according to convergence criteria, if so, entering the next analysis and calculation, carrying out analysis and calculation according to the strain analysis results of the unit of the last round, and modifying the expansion coefficient and the material mechanical property polarities of the unit of the finite element model, and outputting a final calculation result.

Inventors

  • CAO YUHAO
  • JIANG XINSHENG
  • MA CHAO
  • LIU CHANG
  • ZHOU XINGCHI

Assignees

  • 上海卫星工程研究所

Dates

Publication Date
20260512
Application Date
20260205

Claims (10)

  1. 1. A method for thermal deformation analysis of an anisotropic composite structure, comprising: Step 1, establishing a finite element analysis model of an anisotropic composite material structure; step 2, applying boundary constraint conditions and load conditions to the finite element analysis model; Step 3, setting thermal expansion coefficient properties and material mechanical properties of materials in the finite element analysis model; Initializing and setting the material thermal expansion coefficient attribute polarity and the material mechanical attribute polarity of all units in the finite element analysis model, wherein the initializing and setting is to set all the units in a tension state and an expansion state, and endowing the initial material mechanical attribute polarity and the initial material mechanical attribute polarity for all the units according to the initialization; Step 5, performing first simulation analysis based on the initialized material mechanical property polarity and thermal expansion coefficient property polarity, and calculating to obtain the structure internal strain result and the temperature result of each unit of the finite element analysis model; Step 6, based on the temperature results of each unit obtained by the first simulation analysis, checking and correcting the polarity of the thermal constitutive property of each unit, wherein the correction comprises the steps of determining whether each unit expands or contracts according to the temperature state of each unit and correspondingly adjusting the thermal expansion coefficient of each unit; Step 7, based on the strain results of each unit obtained by the first simulation analysis and the adjusted thermal expansion coefficient, checking and correcting the polarities of the force constitutive properties of each unit, wherein the correction comprises the steps of determining whether each unit is in tension or compression according to the strain state of each unit in the direction of each material, and correspondingly adjusting the elastic modulus of each unit in the direction; Step 8, judging whether the current calculated internal strain of the structure meets the requirement according to a preset convergence criterion, if so, executing step 9, if not, updating the material attribute of the finite element analysis model based on the corrected thermal constitutive attribute polarity and the force constitutive attribute polarity, and returning to step 5 to carry out a new round of simulation analysis and polarity correction iteration; and 9, updating the material properties of the finite element analysis model according to the final property polarity correction result when the convergence criterion is met, performing final analysis and calculation, and outputting the thermal deformation result of the anisotropic composite material structure.
  2. 2. The method for analyzing thermal deformation of an anisotropic composite structure according to claim 1, wherein the anisotropic composite structure is an orthotropic composite structure and has material properties in which elastic moduli in three main directions of the material are different from each other and in the same direction, tensile elastic modulus is different from compressive elastic modulus, and thermal expansion coefficients are different in the respective directions and in the same direction, thermal expansion coefficients in an expanded state are different from thermal expansion coefficients in a contracted state.
  3. 3. The method for thermal deformation analysis of anisotropic composite structure according to claim 1, wherein the anisotropic composite is thermally deformed in a free state With temperature increase And expansion coefficient, expressed as: Wherein, the Is a coefficient of expansion matrix; Wherein, the 、 、 Is an element in the expansion coefficient matrix; for orthotropic composites, the coefficient of expansion matrix Part of the elements in (a) In relation to the cell expansion polarity, namely: when the actual temperature T of a finite element model unit is higher than the reference temperature The thermal expansion coefficient is shown as When the actual temperature T is lower than the reference temperature The thermal expansion coefficient is shown as ; The rigidity and strength of the orthotropic composite material structure are related to load conditions, the constitutive equation of the structure is determined by load and constraint conditions, and the constitutive relation is expressed as: Wherein, the In order to be a strain tensor, As a function of the stress tensor, Is a soft matrix; Wherein, the 、 、 、 、 、 、 、 、 、 、 、 Is an element in the compliance matrix; for orthotropic composites, compliance matrix Part of the elements in (a) In relation to the cell stress direction, namely: Wherein, the In the form of a poisson's ratio, 、 Respectively the tensile and compressive elastic modulus; For orthotropic composite materials of opposite tension and compression, when any point in the material is in the local coordinate system When the direction is pulled , Then at Modulus in the direction is tensile modulus At this time The material strength in the direction is tensile strength when in When the direction is pressed Then at Modulus in the direction is the compression modulus At this time The material strength in the direction is the compressive strength.
  4. 4. A method for thermal deformation analysis of anisotropic composite structure according to claim 3, wherein the free thermal strain of the finite element cells in the temperature field environment is derived for the temperature of each cell in the extracted finite element model in combination with the expansion coefficient in a boundary constraint free state The method comprises the following steps: if the relative temperature of a unit obtained is analyzed I.e. the thermal deformation polarity of the unit in the free state is expansion, then in the next iteration calculation If the relative temperature of a unit obtained by analysis I.e. the thermal deformation polarity of the cell in the free state is shrinkage, the corresponding coefficient of thermal expansion matrix is modified in the next iteration calculation to ; Total strain in directions for each cell in the extracted finite element model And calculated free thermal strain of each cell Whether the unit is in tension or in compression is analyzed, i.e.: judging whether the assumption of the previous step is consistent with the actual situation according to the stress direction polarity in each direction of each unit, if so, maintaining the corresponding flexibility matrix of the stress direction of the unit If not, otherwise modifying the element; if a unit obtained by analysis Direction of I.e. the unit Direction is pulled, then in the next iterative calculation If a unit obtained by analysis Direction of I.e. the unit Direction is pressed, then in the next iterative calculation, the corresponding Modified as 。
  5. 5. The method for thermal deformation analysis of anisotropic composite structure according to claim 1, wherein the convergence criterion comprises: when the proportion n of the total number of the unit constitutive relations to be modified is not more than a preset value When n is less than or equal to Stopping the iteration if =0, Then it indicates that no unit constitutive equation is modifiable; or calculate the deviation of the result from the previous iteration step Not exceeding a preset error limit When, i.e. when ≤ Stopping the iteration if =0, Then this indicates that the result is fully converged and the calculation result will no longer change with increasing iterations.
  6. 6. A system for thermal deformation analysis of an anisotropic composite structure, comprising: the method comprises the steps of (1) establishing a finite element analysis model of an anisotropic composite material structure; a module M2, applying boundary constraint conditions and load conditions to the finite element analysis model; setting thermal expansion coefficient properties and material mechanical properties of materials in the finite element analysis model; The module M4 is used for initializing and setting the material thermal expansion coefficient attribute polarity and the material mechanical attribute polarity of all units in the finite element analysis model, wherein the initialization is used for setting all units in a tension state and an expansion state and endowing the initial material mechanical attribute polarity and the initial material mechanical attribute polarity of the thermal expansion coefficient for all units according to the initialization; The module M5 is used for performing first simulation analysis based on the initialized material mechanical property polarity and thermal expansion coefficient property polarity, and calculating to obtain the structure internal strain result and the temperature result of each unit of the finite element analysis model; The module M6 is used for checking and correcting the thermal constitutive property polarity of each unit based on the temperature result of each unit obtained by the first simulation analysis, wherein the correction comprises the steps of determining whether each unit is expanded or contracted according to the temperature state of each unit and correspondingly adjusting the thermal expansion coefficient of each unit; the module M7 is used for checking and correcting the attribute polarity of the force mechanism of each unit based on the strain result of each unit obtained by the first simulation analysis and the adjusted thermal expansion coefficient, wherein the correction comprises the steps of determining whether each unit is in tension or compression according to the strain state of each unit in the direction of each material, and correspondingly adjusting the elastic modulus of each unit in the direction; The module M8 is used for judging whether the current calculated internal structural strain meets the requirement according to a preset convergence criterion, triggering the module M9 if the current calculated internal structural strain meets the requirement, updating the material attribute of the finite element analysis model based on the corrected thermal constitutive attribute polarity and the force constitutive attribute polarity if the current calculated internal structural strain does not meet the requirement, and calling the module M5 to carry out a new round of simulation analysis and polarity correction iteration; And the module M9 is used for updating the material properties of the finite element analysis model according to the final property polarity correction result when the convergence criterion is met, carrying out final analysis and calculation, and outputting the thermal deformation result of the anisotropic composite material structure.
  7. 7. The system for thermal deformation analysis of anisotropic composite structure according to claim 6, wherein the anisotropic composite structure is an orthotropic composite structure having material properties such that elastic moduli in three main directions of the material are different from each other and in the same direction, tensile elastic modulus is different from compressive elastic modulus, and thermal expansion coefficients are different in the respective directions and in the same direction, thermal expansion coefficients in an expanded state are different from thermal expansion coefficients in a contracted state.
  8. 8. The system for thermal deformation analysis of an anisotropic composite structure according to claim 6, wherein the anisotropic composite is thermally deformed in a free state With temperature increase And expansion coefficient, expressed as: Wherein, the Is a coefficient of expansion matrix; Wherein, the 、 、 Is an element in the expansion coefficient matrix; for orthotropic composites, the coefficient of expansion matrix Part of the elements in (a) In relation to the cell expansion polarity, namely: when the actual temperature T of a finite element model unit is higher than the reference temperature The thermal expansion coefficient is shown as When the actual temperature T is lower than the reference temperature The thermal expansion coefficient is shown as ; The rigidity and strength of the orthotropic composite material structure are related to load conditions, the constitutive equation of the structure is determined by load and constraint conditions, and the constitutive relation is expressed as: Wherein, the In order to be a strain tensor, As a function of the stress tensor, Is a soft matrix; Wherein, the 、 、 、 、 、 、 、 、 、 、 、 Is an element in the compliance matrix; for orthotropic composites, compliance matrix Part of the elements in (a) In relation to the cell stress direction, namely: Wherein, the In the form of a poisson's ratio, 、 Respectively the tensile and compressive elastic modulus; For orthotropic composite materials of opposite tension and compression, when any point in the material is in the local coordinate system When the direction is pulled , Then at Modulus in the direction is tensile modulus At this time The material strength in the direction is tensile strength when in When the direction is pressed Then at Modulus in the direction is the compression modulus At this time The material strength in the direction is the compressive strength.
  9. 9. The system for thermal deformation analysis of anisotropic composite structure according to claim 8, wherein the temperature of each element in the extracted finite element model, in combination with the expansion coefficient, yields the free thermal strain of the finite element in the temperature field environment in a boundary constraint free state The method comprises the following steps: if the relative temperature of a unit obtained is analyzed I.e. the thermal deformation polarity of the unit in the free state is expansion, then in the next iteration calculation If the relative temperature of a unit obtained by analysis I.e. the thermal deformation polarity of the cell in the free state is shrinkage, the corresponding coefficient of thermal expansion matrix is modified in the next iteration calculation to ; Total strain in directions for each cell in the extracted finite element model And calculated free thermal strain of each cell Whether the unit is in tension or in compression is analyzed, i.e.: judging whether the assumption of the previous step is consistent with the actual situation according to the stress direction polarity in each direction of each unit, if so, maintaining the corresponding flexibility matrix of the stress direction of the unit If not, otherwise modifying the element; if a unit obtained by analysis Direction of I.e. the unit Direction is pulled, then in the next iterative calculation If a unit obtained by analysis Direction of I.e. the unit Direction is pressed, then in the next iterative calculation, the corresponding Modified as 。
  10. 10. The system for thermal deformation analysis of an anisotropic composite structure according to claim 1, wherein the convergence criterion comprises: when the proportion n of the total number of the unit constitutive relations to be modified is not more than a preset value When n is less than or equal to Stopping the iteration if =0, Then it indicates that no unit constitutive equation is modifiable; or calculate the deviation of the result from the previous iteration step Not exceeding a preset error limit When, i.e. when ≤ Stopping the iteration if =0, Then this indicates that the result is fully converged and the calculation result will no longer change with increasing iterations.

Description

Method and system suitable for thermal deformation analysis of anisotropic composite structure Technical Field The invention relates to the technical field of spacecraft structures, in particular to a method and a system suitable for thermal deformation analysis of an anisotropic composite material structure. Background With the diversification of spacecraft functional tasks, the weight ratio of the payload carried by the spacecraft is increased, and the demand for lightweight spacecraft structures is also urgent. The composite material has the characteristics of high specific strength, strong designability and the like, is convenient for achieving the purpose of light weight design, and is widely applied to the spacecraft structure. On the other hand, the on-orbit use of the spacecraft has the characteristics of high precision and non-maintainability, and the thermal deformation simulation problem brought by the orthotropic composite material structure in the complex space thermodynamic coupling environment also needs to be solved. The anisotropy of the composite material structure not only shows different moduli in all directions, but also shows different tensile and compression moduli and thermal expansion and contraction coefficients in the same direction, and for the situation, most of analysis on thermal deformation response of the composite material structure in engineering is based on the assumption of the same property of elastic modulus and thermal expansion coefficient, and the research on the tensile and compression moduli and expansion coefficient anisotropy of the three-dimensional orthotropic composite material structure is less. At present, the deformation behavior of an anisotropic composite structure is difficult to accurately analyze by general finite element software, and the engineering problem is mainly solved by means of isotropic assumption at present, and the thermal deformation approximate solution is obtained through calculation by commercial finite element analysis software. Zhu et al in A constitutive model for OSB and its application IN FINITE ELEMENT ANALYSIS artificially divide the tensile compression area according to the stress condition of the anisotropic structure, and analyze the stress condition of the structure by adopting different constitutive relations of materials, but the division needs to be manually judged in advance and is not suitable for complex stress conditions. Cao Yuhao and the like clearly propose an iterative algorithm suitable for the mechanical structure of the three-dimensional orthotropic composite material in the self-adaptive algorithm of the three-dimensional orthotropic composite material structure, and the self-adaptive iterative algorithm is provided for the composite material structure widely adopted in a spacecraft, so that the limitation of homopolar assumption of the elastic modulus of the orthotropic composite material in engineering is overcome, the mechanical calculation precision of the orthotropic composite material structure is greatly improved, and the problem of how to perform deformation analysis in a complex thermal coupling environment is still not solved. Xianwei et al in the finite element method of elastic mechanics with different moduli of pulling and pressing, a method for realizing self-adaptive iteration of mechanical analysis is provided aiming at the mechanical characteristics of the pulling and pressing anisotropy of the elastic modulus of materials which are displayed in the growth process of a plurality of organs in stems and straws of plants, the limitation of artificial assumption of stress conditions in the past is overcome, and more complex stress condition analysis can be carried out. But still fails to solve the problem of how to perform deformation analysis in a complex thermally coupled environment. Patent application document CN105631122a discloses a thermal deformation simulation analysis and modeling method of a machine tool large piece, thermal-structure coupling analysis is performed based on general finite element analysis software Ansys, and after finite element analysis is completed, a mathematical model of thermal deformation at a determined position on the machine tool large piece is established by using a polynomial fitting and multiple linear regression method according to the extracted thermal deformation result. The method fully utilizes the advantages of high efficiency and reliability of commercial software to carry out simulation analysis, and is a common method in engineering. However, the method does not further refine the thermal-structural coupling analysis of the thermal deformation of the anisotropic structure, isotropic assumption needs to be made on structural materials for the application of the anisotropic composite structure, and the calculation accuracy is limited. Patent application document CN104537182a discloses an analysis method of the influence of thermal deformation of a le