Residual stress prediction

Linear friction welding is a solid-state joining process that is used to fabricate high-value aerospace preforms. Significant residual stresses are generated in the preforms during the post-weld cooling period which can negatively affect part performance and service life.

This research project focuses on developing and validating  an innovative computational modelling technique to  better understand residual stress formation.

Results show the modelling approach to accurately predict the thermal histories which are validated with thermocouple measurements. The residual stress distributions were found to be in good agreement with the literature.

Further validation of the model against contour method and neutron diffraction measurements will be undertaken.

Impact and findings

This research project focuses on a new modelling approach, bypassing the simulation of the dynamic oscillations of the linear friction welding process, to predict residual stresses. Thermal histories predicted by the numerical models were validated against thermocouples for five sets of experimental conditions.

Results from the mechanical models have shown that increasing the applied pressure on a linear friction weld will reduce the magnitude of the residual stresses by lowering the temperature at the weld interface and its vicinity.