Finite Element, Linear Friction Welding Process, Coupled Thermal Analysis

It is urgent need to develop and manufacture the blisk of dissimilar materials due to rapid progress in high thrust-weight ratio aero-engines. The understanding of basic theoiy and variations of temperature and stress-strain fields during linear friction welding (LFW) is prerequisite for LFW technique of blisks. Based on the above background, this paper investigates vibration model and dynamics properties of LFW machine; the tribology properties between DD3 and Ren ?5 alloys are researched experimentally, and whole LFW process is simulated using the finite element method coupled with thermo-mechanical effect.Based on the patents of linear friction welding machine overseas and basic theory of crank slide mechanism, simple model of LFW recz~rocating vibration system is established, dynamics parameters and power of driving motor are analysed, which will lay a theroretical foundation for designing and manufacturing LFW machine and finite element numerical modeling ofLFWprosess.To the friction couple of DD3 and Ren ?5 alloys, the temperature and torque during friction welding are measured using semi-natural thermocouple and grip-style torque sensor. Parameters data are detected real time by industrial control computer. The formulations of the friction coefficient at initial friction stage and quasi-steady stage are regressed, which will lay a theroretical foundation for finite element numerical simulation of temperature field during LFWprosess.At last, using the finite element method coupled with the thertnomechanical effect and synthetically considering the d~fferent generated heat mechanisms and their converting rule, three-dimensional elasticplastic FEM modcl is established. The geometric nonlinearity, material nonlinearity and contact nonlinearity between dissimilar materials aretaken into account. The welding parameters friction shearing strength, axial shorting and average temperature), physical parameter fields (temperature field, stress field, and deformation field) and their variations during whole linear friction welding process are simulated directly from the properties( F, U, A, p, C) of the welded materials and the welding conditions( the variations of the axial pressure, swing and frequency). The distributions and variations of frictional surface temperature heat power, axial temperature, and axial compressive stress during welding are computed...