Finite Element Analysis For The Thermo-mechanical Coupling Of Tubular Braided Carbon/carbon Composites

The carbon/carbon (C/C) composite is stable, reliable and excellent in mechanicalperformances and thermal properties. It is a particular advantage of C/C composite thatmechanical properties can keep a good or higher level under high temperature. As aresult, C/C composites are widely applied on many high-tech areas such as aerospace,sport equipment, automotive, medical devices and so on. At present, researchers havealready obtained some achievements about C/C composite mechanical performance andthermodynamic properties. However, these studies have their own limitations to someextent, such as carrying on normal conditions or a certain temperature. Furthermore, theresearches of3D braided C/C composites are less than unidirectional C/C compositesand2D C/C composites. This paper investigates tubular braided C/C composites bybuilding a3D model. On these bases, temperature field, stress field andthermo-mechanical coupling field are analyzed and studied.In the first chapter, C/C composites’ properties, the characteristics and advantagesare introduced. The development of C/C composite is summarized in detail both homeand abroad. At the same time, the micro model, the numerical simulation ofthermodynamic properties, analysis of interface mechanics and thermal analysis of C/Ccomposites are reviewed. In the end, the writer explains the purpose of this topic andsignificance of the research.In the second chapter, the finite element format is established on the basis oftheoretical analysis of the temperature field. According to circular tubular braided C/Ccomposite model, the thermodynamic parameters are calculated separately by usingvolume average method. On this basis, numerical calculation and analysis of a rocketnozzle model temperature field are obtained by finite element analysis software.In the third chapter, stress field is analyzed theoretically in the same way and finiteelement format is obtained. The writer analyzes stress field of the model built in thesecond chapter and obtains nephograms of the stress and displacement, curves ofdifferent paths through finite element method. The maximums and their correspondingpositions of stress and displacement, stress concentration regions are stated at length.The displacement and stress of the model under different pressure loads are simulatedand analyzed by numerical method.In the fourth chapter, the writer analyzes the thermo-mechanical coupling theory and builds its finite element format. And the sequential coupling by finite elementmethod is discussed. Then, the displacement field and stress field of the model as aboveunder temperature and pressure loads are simulated through the finite method. Thenephograms got from simulation are analyzed. And stress field and displacement fieldare compared in the case of presence and absence of temperature loads respectively.Finally, the displacement field and stress field of the model are simulated and analyzedon the condition of constant temperature load and different pressure loads through finiteelement method.