Multi-spot ultrasonic welding of thermoplastic composite single-lap joints: Effect of spot spacing and number of spots on weld strength

Thermoplastic composite spot welded joints are more well-suited for carrying shear load rather than peel load. However, peel load is difficult to be eliminated in single-lap joint configuration. In this paper, a series of mechanical tests were carried out to study the effects of the spot spacing and the number of welded spots on the secondary...

Towards robust sequential ultrasonic spot welding of thermoplastic composites: Welding process control strategy for consistent weld quality

The research in this paper is an essential part of a bigger effort on developing robust sequential ultrasonic welding of multi-spot welded joints in thermoplastic composites. It mainly focused on assessing the impact of the changes in boundary conditions on the welding process and whether it could be circumvented by using an appropriate...

Towards high-quality multi-spot-welded joints in thermoplastic composite structures

Ultrasonic welding is a promising assembly technique for thermoplastic composites and it is well-suited for spot welding. In this study, two typical welding process control strategies, i.e. displacement-controlled and energy-controlled welding, were selected to manufacture spot-welded joints. The influence of different boundary conditions,...

Mechanical behaviour of thermoplastic composites spot-welded and mechanically fastened joints: A preliminary comparison

The in-plane and out-of-plane mechanical behaviour of both ultrasonically spot-welded and mechanically fastened joints was investigated by double-lap shear and pull-through tests, respectively. Spot-welded specimens showed comparable onset failure load and significantly higher joint stiffness compared to mechanical fasteners when carrying shear...