The quest of a universal fracture law governing the process of slow crack growth

✍ Scribed by James D. Lee; Harold Liebowitz; Kung-Yan Lee

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 1006 KB
• Volume: 55
• Category: Article
• ISSN: 0013-7944
• DOI: 10.1016/0013-7944(95)00249-9

✦ Synopsis

A nonlinear finite element analysis, based on the incremental theory of plasticity with isotropic hardening rule, has been performed for the process of slow crack growth in center-cracked specimens made of 2024-T3 aluminum alloy. With experimental data relating the applied stress and the crack size taken as input, it is found that the plastic energy and the crack size are linearly related during the entire process of slow crack growth. The variations of various fracture parameters, such as crack opening displacement, crack tip opening angle, crack tip stresses and strains, elastic strain energy density and energy release rate, during the slow crack growth process are also presented. Moreover, the linear relation between the plastic energy and the crack size, replacing the experimental applied stress vs crack size curve, may also be taken as the input and generate a crack resistance curve which is in excellent agreement with the experimental result. This finding enables one to establish a fracture law which can be used to identify the onset of slow crack growth and the onset of fast fracture. A discussion has also been made on the general guiding principle in formulating a universal fracture law.