A study of the adhesive joints and crack propagation using a global-local finite element method.pdf

American Institute of Aeronautics and Astronautics 1 A Study of the Adhesive Joints and Crack Propagation Using a Global-local Finite Element Method Mohammad M. Islam1,2 and Rakesh K. Kapania3 Virginia Polytechnic Institute and State University, Blacksburg, Virginia, 24061 Accurately capturing the stress distribution in an adhesive joint requires discretizing the adhesive layer with a very fine finite element mesh. Since such a simulation requires high Computational Processing Unit (CPU) time, researchers are looking for alternative methods to simulate adhesive joints for saving the CPU time. Another high CPU requiring study is the evaluation of delamination growth in adhesive joints and crack propagation in brittle materials using cohesive zone modeling along with the very fine finite element mesh for the bulk material. To reduce these computational times, a possible alternative is to use a global- local finite element method. Therefore, both the crack propagation and the characteristics of adhesive joints were studied using a global-local finite element method. Three cases were studied using the proposed global-local finite element method: a) an adhesively bonded Double Cantilever Beam (DCB), b) an adhesive lap joint, and c) a three-point bending test specimen. Using global-local methods, in a crack propagation problem of an adhesively bonded DCB, more than 80% data storage space and more than 65% CPU time requirement could be saved. In the adhesive lap joints, around 70% data storage space and 70% CPU time requirement could be saved using the global-local method. For the three-point bending test specimen case, more than 90% for both data storage space and CPU time requirement could be saved using the global-local method. Nomenclature ? = penalty constant with a large magnitude δ = separation δc = critical separation in single mode of fracutre δm = maximum separation in single mode of fracture δnn,ss,tt = separation along the local