A Cohesive Zone Model for Studying Crack Growth in Materials and Structures

This paper presents a cohesive zone model and explores its capacity for predicting crack growth in materials and structures. An exponential cohesive law was implemented for the specific case of monotonic loading and applied to crack growth simulation, in three-dimensions, in thin fracture specimens made from the chosen material of interest. The cohesive law is governed by the two parameters, cohesive strength and cohesive energy, and our parameter study revealed the cohesive strength to be a more influential parameter. The cohesive parameters were calibrated for the commercial aluminum-copper-magnesium alloy 2024 in the T3 temper by comparing the finite element predictions with experimental test results obtained for a compact-tension specimen. Middle-cracked tension test specimens having different ratios of the crack length were modeled using the calibrated parameters and the numerical results showed good correlation with the experimental test results