Linear Elastic Fracture Mechanics (LEFM)-Based Single Lap Joint (SLJ) Mixed-Mode Analysis for Aerospace Structures

摘要

This paper investigates the study of crack propagation on single lap joint (SLJ) using cohesive zone modeling (CZM) for aerospace applications. To carry out the above task, linear elastic fracture mechanics (LEFM) approach using finite element methods was used to study the damage propagation in adhesively bonded joints. A traction-separation law was used to simulate the mode-II and mixed-mode-I+II interfacial fractures of adhesively bonded specimens loaded (quasi-static) in three-point bending and mixed-mode bending. An initial crack opening was introduced at the interfaces of the adherend/adhesive. The boundary conditions for SLJ have been set to carry out the interlaminar mode-II (shear mode) and mixed-mode fracture analysis by end notched flexure (ENF) and mixed-mode bending (MMB) methods. Optimized cohesive parameters from the literature survey were used for simulation of the tests, and same parameters have been validated to continue the research work focusing mainly on progressive delamination in SLJ. The total displacement of 10 mm was applied at free end, and as a result the reaction forces at fixed end steadily progressed up to 60% of applied displacement; further it has been observed the model starts failing by reduction in load versus displacement slope curve.