C / C Composite Multi-physical Fields Cvi Process And Its Simulation Of The Braking Process Temperature Field Research

Chemical vapor infiltration (CVI) process is a key process to fabricateCarbon/carbon composites. Study and analysis of change law of CVIparameters are very necessary to efficiently control CVI process becauseof complexity of CVI reaction. Computer simulation technique has manyadvantages such as low-cost, time-cost and simulation under idealcondition, and its simulation result can give a helpful reference tooptimize CVI process.In this paper, the CVI process model of C/C composites wasimproved on the base of previous reports. The so-supposed modelconsidered the equation of gas mass, the heat conduction equation inperform and pyrolysis and deposition of gas. The growth model of cubicarray of perpendicular fibre cylinders was established in order torepresent the porous structure of the preform and the composite.According to the multi field CVI process, the finite element method andMatlab technical computing soft-ware was used to edit program and solve,simulating the physical field change during CVI process. Because theelectromagnetism influence on CVI process was not considered, Comparewith experiment result and simulation result, the simulation increasedensity velocity is half of the experimental value in beginning and middleperiod, the simulation increase density velocity is generally equal to theexperimental value in latter period, The simulated last bulk density isgenerally less than the experimental value. As a result, the multi physicalfield CVI process model can give the change of temperature and gaspressure and bulk density, and the research of electromagnetism influenceis significative to optimize the multi physical field CVI process andsimulation model. The simulated results can give a contribution for theselection of process parameters and the formation mechanism of pyrolyticcarbon produced via multi field CVI process.The frictional temperature field and thermal stress field is animportant direction of tribology field. Based on the C/C composite brake testing, a 3D cycle-symmetric finite element model was set up with thefriction heat as the transient moving plane heat source. The coefficients ofheat transfer were estimated by heat transfer theory. The braketemperature field is calculated with finite element software ANSYS, andthe temperature field with different time and the thermal stress field withthe temperature increasing are given, the simulated results were inagreement with the experimental results.