Microstructure Optimization And Finite Element Simulation Of Three-dimensional Woven Heat Protection Material

3D Woven Thermal Protection System(WTPS)is a kind of 3D Woven composite material with double-layer density Woven,which has the advantages o f high specific modulus,specific strength,damage toleranc e,shear strength,impact damage resistance,designabilit y,corrosion resistance and high temperature resistance.Compared with 2D braided laminates,3D woven composites have better overall performance.The connecting fiber bundles can be arranged in the thickness direction to strengthen the junctions between the layers and give the material a higher shear strength.Due to its good performance,3D woven composites can meet the requirements of aerospace,military products,building materials and artificial biomaterials.Experimental characterization,theoretical analysis and numerical simulation were used to study the compression performance of 3D woven thermal protection materials.The parameterization of WTPS thermal protection material fiber skeleton structure was realized by programming.The influence of WTPS thermal protection material fiber skeleton structure parameters on its upwar d modulus was studied by finite element simulation.According to the actual mechanics requirements of the aircraft reentry process,the microstructure design of WT PS thermal protection material was carried out,which broke through the key technology of continuous control of the microstructure of WTPS thermal protection material,and provided a set of effective and feasible design scheme for the micro structure design of 3D braided material.Firstly,compression tests of WTPS thermal protection materials were designed to obtain the mechanical properties of 3D woven thermal protection materials.The fiber bundle inside WTPS thermal protection material was analyzed theoretically by the method of mixing rate,and the elastic property parameter matrix of the fiber bundle was obtained.Then the volume average method was used to calculate the overall texture of WTPS thermal protection material,and the mechanical properties of WTPS thermal protection material were obtained.Secondly,simulation analysis was carried out,and the python language was used to encode the 3D weaving form of WTPS fiber bundle architecture and the matrix with reserved section,and the binding between the matrix and fiber bund le was set up to establish the geometric model unicellular cells of different textures and set the periodic boundary conditions of the unicellular model.The mechanical properties of WTPS were calculated by introducing abaqus and applying periodic boundary conditions under different loading conditions.The elastic constants o f upper cell,lower cell and whole cell were obtained by calculating the elastic properties of the material using the principle of homogenization.The accuracy of the finite element model is verified by the error analysis of experimental and theoretical results.Finally,the INP file of the 3D woven thermal protection material unicell model was modified to optimize the model parametric design.Isight integrated abaqus was used to optimize the target of the parametric model,and variables were set to study the influence of parameter changes on the overall mechanical properties of the material.Parameter variables include fiber bundle stiffne ss,longitudinal fiber bundle arrangement density,zonal fiber bundle arrangement density and junction depth.Taking the compression modulus and shear modulus as the targets,the mesoscopic structural parameters of 3D woven thermal protection materials were optimized,and the optimal texture form was obtained in combination with the actual working conditions,providing reference for the preparation of materials.