An Exponential Drucker‐Prager Constitutive Model of Polyurethane Adhesive for Finite Element Model Simulation

ABSTRACT The elasto‐plastic model‐based finite element method (FEM) simulation can graphically describe the nonlinearly mechanical response of adhesives to various loadings. Its prediction accuracy significantly hinges on the constitutive models of the adhesives. In this study, the plasticity property of the polyurethane adhesive is characterized by the Exponential Drucker‐Prager model (EDPM), and the model parameters are identified through tensile and shear tests. The FEM simulations and validation experiments reveal that there exists a monotonically increasing nonlinear relationship between the bonding thickness and the maximum stress of the adhesive joint as well as the stress peaked in the end of the single‐lap‐joint (SLJ), while the joint strength shows a monotonically decreasing tendency with the increment of the bonding length, and the stress at the joint end is distributed uniformly. The EDPM‐based constitutive model of polyurethane adhesive can accurately delineate the elastic–plastic deformation process of the bonding joints, which lays a theoretical foundation for optimizing the material properties of the adhesive and the bonding process.