On the sensitivity of the ultrasonic welding process of epoxy- to polyetheretherketone (PEEK)-based composites to the welding force and amplitude of vibrations

This paper addresses the sensitivity of the ultrasonic welding process for joining dissimilar composites to variations in either the welding force or amplitude of vibrations. For that, carbon fibre (CF)/epoxy specimens were welded to CF/polyetheretherketone (PEEK) specimens, through a polyetheretherimide (PEI) coupling layer co-cured with the CF/epoxy material. It was found that reducing either the welding force or the amplitude of vibrations caused an increase in the heating time and maximum temperatures between the coupling layer and CF/epoxy adherend. In addition, local signs of thermal degradation were found in the CF/epoxy adherend even at welding conditions that resulted in the highest strength. However, such alterations were not significant enough to have an apparent effect on the maximum lap shear strength of the welded joints.