Analysis of the cohesive zone and crack length correction in the adhesively bonded double cantilever beam specimen

Abstract

ABSTRACT The double cantilever beam specimen has been increasingly employed to enable the development of cohesive zone models for adhesive joints. Evaluation of the traction–separation law (TSL) requires elaborate experimental techniques and usually relies on data measured until the crack initiation point. Nonetheless, current standards stipulate fracture energy measurements under steady-state crack propagation. This paper investigated the influence of the cohesive zone on the commonly used corrected beam theory data reduction scheme. Analytical solutions for the elastic–perfectly plastic, bilinear, and trapezoidal laws were developed using a beam model. The role of the elastic traction decay zone was found to be significant for high strength moderately tough adhesives. Nevertheless, the results showed that the sensitivity of the crack length correction to the cohesive zone can be exploited to obtain approximate TSLs.