Finite element modelling of interacting indentation, flexural, and delamination damage in lap joints of composites

Abstract

Composite lap joints are essential for various applications, such as aircraft wings, piping networks, sporting equipment, and civil engineering works. Low-velocity impact on such joints is a common occurrence in real-life situations. The response of these joints under such impacts is quite complex. This involves multiple interacting damage modes that include delamination failure, ply failure (in-plane damage), and bond interface (joint) failure. These damages may lead to significant degradation of joint strength without apparent complete failure. Thus, it is very important to predict the response and behavior of lap joints under such impacts. The objective of this study is to demonstrate the methodology for the evaluation of damage parameters for built-in damage progressive models in ABAQUS. By introducing the concept of characteristic length to address mesh dependency, the method ensures accurate and reliable computation of damage parameters. Further, the proposed progressive damage model was improved to include the laminate (in-plane) damage, in addition to delamination and bond failure. Finally, the proposed methodology was validated by applying it to a real-world lap joint impact problem. The present study can be helpful in the initial design phase of composite structures, as it provides a consistent and easy-to-use methodology to evaluate damage parameters for practical impact simulation problems.