Study On Cylindrical Lining Structure Of C / C Composites Based On Jones - Nelson Constitutive Model

As one of the key components of the nozzle, throat is the minimum channel of the solid rocket motor nozzle structure, which holds the scheduled working pressure,makes fuel gas from subsonic flow to supersonic flow, and produce thrust. Because of the pretty thermal and mechanical properties, carbon / carbon composite is used in the SRM nozzle structure widely. However, because of the poor recognizing of the material’s complex heterogeneous property, the carbon / carbon composite is a lack of right constitutive relation, which causes the great errors in simulating. Based on the engineering practice,studies the thermal structure of the throat of solid rocket motor with the study of the Jones-Nelson constitutive relation of the carbon / carbon composites.The chapter 2ndstudies and summarizes the mechanical properties test method of the carbon / carbon composite in recent years, learns the advanced data processing, sample designing, sampling requirements etc. Based on the experimental conditions of composite materials in China, completes the related experiments about the carbon / carbon composites mechanical properties, gets the carbon/carbon composite mechanical properties data. Through analyzing the data, summarizes the material’s properties of carbon / carbon composites such as anisotropy, dual extension-compression elastic modulus and damage evolution, which providing support for the composite constitutive relationship studies.Based on the data from the carbon / carbon composites mechanical experiments, the chapter 3rdgets the Jones-Nelson model parameter through linear regressing the text results of mechanics experiment. Then uses the enrichment theory of Jones-Nelson constitutive model spinning the model to make the model can be used for constitutive model research of composite materials under complex loading conditions; combined with the influence factors of material’s properties including dual extension-compression elastic modulus,anisotropy and damage evolution, using the weighted flexibility correction model revised the Jones-Nelson model.The chapter 4th establishes and improves on the flow field calculation method innozzle which based on the basis of heat transfer theory, and compiles the corresponding program, combining with the theory of Jones-Nelson constitutive model, does the simulating calculation, completes the experiment in the same time. Compare the results,the temperature field of simulating calculation is basically same as the experiment results, error is less than7.2%,and complete the error analysis. The strain field of simulating calculation is basically same as the experiment results. Without considering the Jones-Nelson model, the error of axial strain is less than 8.3%, the error of hoop strain is less than 23.6%. Considering the Jones-Nelson model, the error of axial strain is less than2%, the error of hoop strain is less than 4.9%. The result shows that Jones-Nelson model with the weighted flexibility correction model can describe the constitutive relation about carbon/carbon composite material excellently.