Creep failure mechanism in single-lap joints

Abstract

The paper presents a study on adhesive creep mechanisms and failure in single lap adhesive-bonded joints, focusing on their time performance and durability. Adhesive connections, while advantageous for their uniform stress distribution, are susceptible to creep-progressive deformation under sustained loading. In the study, the adhesive creep behavior is modeled, employing advanced nonlinear FEA techniques and a probabilistic approach to capture the material complexities within the joint. Cohesive zone models and traction–separation laws are used to simulate crack initiation and propagation within the adhesive layer. The random field approach is used to govern the distribution of internal material imperfections. The results highlight the impact of creep on joint stiffness, ultimate strength, and damage progression over time, offering insights into the critical parameters affecting joint reliability and providing a basis for optimizing adhesive materials in structural applications. The material parameters used in the FE analysis were determined through experimental tests, and the numerical results were validated against experimental studies. The study demonstrates that the load capacity of the single-lap joint is significantly influenced by material imperfections, with their impact depending on both their percentage and location.