Numerical Simulation Analysis Of High Temperature Responses Of Low-density Carbon/Phenolic Composites

When the spacecraft passes through atmosphere at hypersonic speed,the surface of spacecraft with the complex heating environment puts forward the higher requirements of thermal protect materials.As one kind of new generation of lightweight thermal protection materials,low-density carbon/phenolic composites with excellent thermal insulation properties have been widely used as thermal protection materials for spacecraft.When resin-based thermal protection materials undergo high temperature conditions,there exist a series of complex physical and chemical reactions,and coupling effects of temperature,pressure and displacement fields.Considering the multi-field coupling effect under high temperature conditions and analyzing the high temperature thermal response of low density carbon/phenolic composites,it is of great significance to the structural design analysis and evaluation.In this paper,the finite element method is used to analyze the coupling problems of heat conduction,gas transmission and thermal deformation.The influence of the surface recession of the material is also considered.In addition,the single-side quartz lamp heating experiment of the low-density carbon/phenolic composites is carried out to study the multi-physical field problems.Firstly,the heat transfer and mass transfer equations of low-density carbon/phenolic composites are derived.The temperature/pressure/displacement multi-field coupling of materials under high temperature conditions is accomplished using finite element method.The predicted results using the established model are validated by several typical examples excerpted in literatures.In addition,the influence of model size,grid density and calculation increment size on the calculation results are studied.Secondly,the one-side quartz lamps heating experiment for the low-density carbon/phenolic composite material was conducted.The macroscopic morphologies and the microstructure evolution of the cross section along the heating direction of the material after heating experiment were observed,which also compared with the oxyacetylene heating experimental results.The thermal conductivity of the material after carbonization for the quartz lamps heating environment was determined by a large number of the numerical results and comparing with the experimental results.Finally,the surface recession of the material under high temperature conditions is taken into account in the multi-field coupling computations.The ALE method is used to simulate the recession process of the material.The surface ablation of the material combining with the volume ablation is accomplished to study the high temperature response of the low-density carbon/phenolic composite materials.The calculated results for a typical example are also validated by comparing with the PATO calculated results in literature.