Emulation Of Structures And Multi-field Coupling Numerical Simulation Of Forming Process For Carbon Fiber Composites

Carbon fiber reinforced composites have been widely used in military and aerospaceindustries due to its superior performance，the core manufacturing technology of whichincludes the skeleton structure of woven preform and the curing forming process. As thestructure in micro scale is very complex, meanwhile the forming course becomes quiteuncontrollable under the influence of multiple physical and chemical changes, the testingmethod based on history experiences is used more than the other methods in actualproductions. That leads to an increase in manufacturing cost and the stability of productquality also can not be guaranteed.Utilizing the three-dimensional visualization and numerical simulation techniques asdevelopment tools, this paper carried on the researches of process simulation containing bothweave structures and autoclave forming separately oriented to the carbon/carbon and resinmatrix materials. Relevant softwares with independent property rights were developed, whichbrought high guiding significance to the principle analysis of actual process and thequantitative analysis of preform structures.Based on the structural characteristics of composite reinforced by carbon fiber and axialcarbon rod mix weaved4D, combined with the secondary development of UG and parametricdesign technology, this paper achieved the function of intelligent structure simulation on theUG modeling platform. Parameter calibration, user guide and other support mechanisms werealso adopted to provide for a good interactive user interface. The main modules consisted ofsingle-face slice, multi-faces slice, pore space block and reverse of parameters, which couldbe applied to establish the quantitative relationship between weaving process and porestructures as parameters’ selecting and calculating tools.The inner temperature and pressure environment of autoclave was simulated by theprofessional fluid simulation software Fluent, then the simplified method of boundaries forhot pressing process could be easily given. A three-dimensional mathematical model for modules of thermo-chemical, resin flow and fiber compaction process was built, which couldwell describe phenomena such as heat conduction, curing reactions, porous flow and laminatecompression. According to the implicit finite difference method, several course governingequations were changed into discrete schemes, the ways how various parameters involved inthe solution procedure should be chosen and calculated were provided either. The wholedevelopment of the simulation software was completed in the programming environmentVS2010.Through a typical example analysis based on the standardization experiment, thereliability of process model and numerical algorithms adopted in this paper was validated.Couples of control variables based parameters comparison tests have also been designed,focusing more on the effects of scale changes, thermal conductivity of materials, temperaturegradient existed in the boundaries, heating rate, tooling system and curing pressures. Finally,the multi-physics field coupling numerical model example was realized, and types ofabnormal simulation results got reasonable explanations through a comprehensiveconsideration of some specific process parameters.