Ultrasonic welded joint failure mode of glass fiber/polyetherimide composites

Abstract

Failure modes of ultrasonic welding joints were investigated by using glass fiber/polyetherimide (PEI) composite material as a base material, and the mechanism of welding pressure with different failure modes and the effects of failure modes on joint strength were explored. The results demonstrate that ultrasonic welding joints have six failure scenarios. Peeling of PEI film and the base material surface on both sides, peeling of PEI film and the base material surface on one side, peeling of surface fiber and surface resin, laminate delamination, fiber breakage, ablation damage respectively. The welding pressure mainly affects the proportion of the first three failure modes. When the welding pressure increases, the proportion of the second failure mode is obvious, meantime the proportion of the first failure mode gradually decreases, the welding pressure mainly affects the proportion of the first three failure modes.The welding joint failure is often a mixed failure generated by the coupling of the abovementioned six failure modes rather than a single failure mode. The evolution of heat distribution with P w was simulated using COMSOL. The simulation curves represent the evolution of the weld interface temperature at different position.