An Efficient Numerical Modelling Approach to Predict Residual Stresses in Ti-6Al-4V Linear Friction Welds

摘要

There is increasing industrial interest in linear friction welding (LFW), due to its ability to manufacture high-value aerospace preforms, such as bladed disks. Unfortunately welding can produce significant residual stresses which can negatively impact performance. Computational models can provide an insight into how these residual stresses are formed, however conventional models that include the mechanical processing are extremely computationally expensive. Therefore this work presents an innovative and computationally efficient finite element model for predicting the residual stress formation in Ti-6Al-4V LFW. The model assumes that the residual stresses are predominantly due to the thermal history - not the dynamic oscillations. This assumption is proved by comparing models with and without the mechanical movement and the associated shear stresses and strains. The paper demonstrates the ability of the innovative modelling approach to accurately predict the thermal histories and residual stresses associated with the process. Thermal results are confirmed with thermocouple measurements. The effect of the applied pressure on the development of residual stresses was studied. The modelling predictions suggest that the higher the applied pressure, the lower the peak of tensile residual stress. These findings have significant, practical benefits and may aid further industrialisation of LFW.