Development of a Computer Program for the Design of Adhesive Joints

Abstract

Adhesive joints are increasingly being used due to their improved mechanical performance and a better understanding of the mechanics of failure. To predict the joint strength, one must have the stress distribution and a suitable failure criterion. The literature contains many closed-form solutions for the stress distribution. However, the models are sometimes difficult to implement and use. The objective of the present work was to compile existing models of increasing complexity into user friendly software. Three main situations were considered: elastic adherends and adhesive, elastic adherends with nonlinear adhesive and nonlinear analyses for both adherends and adhesive. The adherends were both isotropic (metals) and anisotropic (composites). The joints considered are the single and double lap joints for most of the models. However, a sandwich model initially proposed by Crocombe can be used for any type of joint provided the boundary conditions are known. For each model proposed the compatible failure criteria are included to enable the user not only to have the stress distribution but also the failure load for a given joint/load scenario. Experimental tests corresponding to the three cases described above were carried out to validate the models implemented.

Keywords:

• Adhesive joints
• Closed-form models
• Design
• Software

ACKNOWLEDGMENTS

The authors thank the University of Porto (Project IPG96/2007) and the European Union (Projects Cordis FP6 31321 and METRI-2) for supporting part of the work presented here. The experimental SLJ tests were performed at IFREMER (Brest, France) with the help of Dr. Peter Davies from IFREMER and Prof. Jean Yves Cognard from ENSIETA (Brest, France).