Investigation of the Influence of Delamination Characteristics on the Mechanical Properties of CFRP

Abstract

Carbon fiber reinforced polymer (CFRP) composites have been widely used in aviation, aerospace and other fields due to their excellent mechanical properties. However, it is difficult to observe delamination damage during the manufacturing, machining, assembling as well as transportation of composite materials, especially for joint structures. The delamination around joint hole is one of important factors for their service performance. In this paper, a model of composite laminate with delamination damage is established by combining numerical simulation methods and the experimental investigation of CFRP parts with delamination defects. Then, the influence of different delamination characteristics (diameter, position and shape) on the mechanical properties and failure process of the laminate under different loading conditions were investigated, and the results were verified through experimental validation. By comparing the experimental and simulation results, it can be concluded that all three factors have a great influence on the compressive static load strength and compressive fatigue life of the laminate, and the form of delamination expansion and stress distribution cloud diagram of the laminate under each delamination feature are also studied, to investigate the failure mechanism and the type of delamination expansion of the laminate. Finally, ANOVA was used to analyze the effects of different delamination characteristics on the compression strength and fatigue life of the laminates.