Failure mode shift of sandwich composite L-Joint for ship structures under tension load

This paper investigates the ultimate tension failure behavior of sandwich composite L-joints for ship structures. Experiments are conducted on L-joints whose transitional area radius (R) are 45 mm, 90 mm and 180 mm. Matrix tension damage is identified through sudden changes in strain values. Results show significant differences in the damage process and failure modes between the different L-joints. Simulations are conducted using a progressive damage method that could differentiate between matrix tension damage and fiber tension break. Simulations present matching results that clearly describe the damage expansion and final failure of each type of L-joint. Further analysis with a series of simulations reveal a perspicuous map of the transformation of the damage process and failure modes. Additionally, the failure map of two more types of L-joints are provided. The results of the "extended L-joint" shows the great potential if the original L-joints were not impaired by the bonding connection. The "improved L-joint" offers a significant mechanical performance improvement compared to the original L-joint.