Fatigue characteristics of sandwich composite joints in ships

Abstract

The aim of this study is to investigate the fatigue characteristics of sandwich composite joints in ships based on the experimental and numerical methods. Sandwich composite L-joints are subjected to tension-compression, tension-tension and compression-compression fatigue loading at several load levels. Residual stiffness, strain, and surface temperature were measured during fatigue tests. The experimental results show that the sandwich composite L-joints have lower fatigue lives than expected and the fatigue load amplitude has a perceptible effect on the fatigue lives of the joints. In order to illustrate the influence of stress concentration on fatigue life of the joints, a quasi-static numerical analysis was conducted. Moreover, the fatigue damage mechanism and damage growth were revealed by experimental observation, stiffness curves and numerical stress distribution. Finally, a damage model based on the maximum displacements is proposed for the fatigue life prediction of the sandwich composite joints, and the results show that the predicted fatigue lives are in good agreement with the experimental ones.