A modified DCB specimen to determine mixed mode fracture toughness of adhesives

Abstract

The purpose of this work is to demonstrate the applicability of a relatively simple test specimen formed of unlike adhesively joined double cantilever beams (UDCB) for determining the mixed mode components G I and G II of the adhesive's fracture toughness. This work presents an approximate analysis based upon the Green's functions method for shear deformable beams that enables the evaluation of G I and G II without resort to finite element computations. It is shown that the current approximate analysis, which is essentially one dimensional, provides a simple, engineering type, solution that agrees with FEM results to within about 5%. It is demonstrated that a wide range of G II/ G I ratios can also be obtained by applying a single load to any one of the UDCB, which may facilitate the test program.