A Yoffe crack/cohesive zone model for a steady state moving crack

• A Yoffe crack/cohesive zone model is presented for steady state crack propagation.
• The rear crack tip closes and only one cohesive zone exists at the front tip.
• The new model eliminates the dilemma of the standard Yoffe crack model.
• The model can be used to validate numerical models using the cohesive zone approach.

A Yoffe crack/cohesive zone model is presented to investigate steady state crack propagation in an infinite medium. In the current model, the rear crack tip closes and a cohesive zone exists only at the front crack tip during crack propagation, which eliminates the dilemma in the standard Yoffe crack/Dugdale zone model that the crack length remains constant but the rear crack tip opens up. The cohesive zone length and the crack tip opening displacement (CTOD, the opening at the physical crack tip) are determined in closed forms using a Fourier transform/integral equation approach. It is found that the cohesive zone length and CTOD differ significantly from those in the standard Yoffe crack/Dugdale model in which two cohesive zones exist at both crack tips during crack propagation.