An elastic-plastic interface constitutive model for combined normal and shear loading : application to adhesively bonded joints

Abstract

The behavior of mechanical adhesive interfaces when subjected to a variety of separation and slide loading modes, strain rates, and thermal conditions are of interest in many technical areas. An elastic-plastic constitutive model for adhesive interfaces subjected to combined normal and shear loading has been developed and numerically implemented in a finite element software package. The traction-separation behavior is defined for the normal and shear mechanisms and a displacement jump angle is found to drive the behavior of the initial strength values, as well as the critical and failure displacement jumps of the separate mechanisms that are used to define the model. A set of calibration experiments are performed to fully define an aluminum/adhesive/aluminum system subjected to five different combined loading angles. Tension and shear tests on the aluminum/adhesive/aluminum system at three different rates are used to determine the sensitivity of the adhesive interface to strain rate. The capability of the constitutive model is then explored for the geometry of bonded curvilinear blocks at different loading angles and for a notched four point bend geometry. In addition, a rate dependent elastic-plastic interface constitutive model for combined normal and shear loading is presented, and an initial calibration of inelastic strain rate sensitivity parameters are found.