Bending of fusion-bonded thermoplastic single lap joints.

• The fusion-bonded Single Lap Joints under four-point bending load were analysed experimentally and numerically. • The effect of the geometry of the overlap terminus was evaluated, with a special interest in the overall joint strength and failure mechanisms. • The effects of notch geometry on the joint performance were considerable. • The failure always started at tensile edge of the overlap, irrespective of the geometry of the overlap termination. The assembly of thermoplastic composites is one of the most important issues for their reliable use in the aerospace and automotive industries. Assembly through co-curing is a process that enables simultaneous bonding and curing of adherends and is a preferable option for these industries. This paper presents a study of fusion-bonded, co-cured single lap joints with thermoplastic adherends that were subjected to four-point bending. Processing of the joint created a 45° notch at one edge of the overlap. The effect of this notch on the strength of the joint was assessed in tension and compression by flipping the joint. Compared to samples without such notches, experiments indicated that the tensile stresses in the vicinity of the notch decreased the maximum load and applied displacements at failure initiation by about 30 % and 33 %, respectively. In order to better understand this behavior, the joints were also analyzed using finite element simulations. The initial failure was predicted using the Maximum Stress Theory. Both experimental and numerical results were consistent up to the initial failure. The analysis did not account for the subsequently observed interlaminar delamination in the adherends. This type of failure would most likely be approached using measured interlaminar traction-separation relations in a cohesive zone modelling approach. [ABSTRACT FROM AUTHOR]