Indian Journal of Science and Technology

Abstract

Validation of an adhesive joint strength is by and large done through crack propagation analysis influenced by the loading modalities leading to different testing methodologies. The DCB test method is extensively used under more-1 loading to study the fracture and delamination toughness of adhesive joints. The significance and suitability of using the test when the hardener-resin proportion of the adhesive is varied needs to be scrutinized. Three mild steel DCB specimens were analysed incorporating the proportion-variation. The analysis revealed the need of using the Cohesive Zone Model (CZM) to study the crack propagation in all the specimens as a pattern of inconsistent proportionality emerged between the resin proportion and the crack propagation. The graphs converged to a particular degree between the experimental and the analytical realms which further instigated the need of modeling of the entire specimen inclusive of the adhesive layer through Finite Element Analysis. The obtained results provided insights on stress distribution inside the adhesive layer when crack propagation takes place in the specimens. The proportion variation done in a systematic manner is seen as a key factor in improvisation techniques for analysis when efforts are undertaken to introduce modalities in crack propagation direction control.
Keywords: Adherent Material, Cohesive Zone Model, Double Cantilever Beam, Fracture Toughness, Hardener-Resin Proportion, Resistance Curves