A simple and accurate method for computing stress intensity factors of collinear interacting cracks

The multi-site damage problem of aging aircraft has raised the issue of obtaining accurate stress intensity factors of interacting collinear cracks under external load. The simple approximate technique proposed by Kachanov (1987) [8] is specialized in this work to arbitrary length collinear cracks with arbitrary spacing under far field tension. This approach yields simple formulas that can be used to quickly and accurately assess the mode I stress intensity factors of any number of collinear cracks in an infinite body under far field tension considering interactions between all cracks. The advantage of this approach over others is that it is simple, has good accuracy, and is very efficient. Kachanovʹs method is further enhanced here such that a repeating subpanel of cracks of arbitrary number, size, and spacing can be modeled implicitly with resulting efficiency gains. The effect of interaction cracks can be used to build up stress intensity factor solutions for more complex geometries. Several numerical examples and timing studies are used to demonstrate the efficacy of this approach.