Fracture mechanics for multilayers with penny-shaped cracks subjected to dynamic torsional loading

This paper provides a method for investigating the penny-shaped interface crack configuration in orthotropic multilayers under dynamic torsional loading. The multilayer is said to have finite height along the direction normal to the interfaces. By utilizing Laplace transform and Hankel transform technique, the general solution for each layer is derived. The Dual integral equations of the entire elastic region are then obtained through introducing the mechanical boundary and layer interface conditions. The stress intensity factors (SIFs) are computed by solving Dual integral equations numerically in Laplace transform domain. The solution in time domain is obtained by utilizing numerical Laplace inverse. Numerical example shows that the main advantage of the present model is its ability for treating multiple crack configurations in multilayers and the number of layers can be sufficiently large. The present model can also treat crack problems for functionally graded materials (FGMs) with arbitrarily distributed and continuously varied material properties by subdividing the FGM into a number of thinner layers such that the elastic properties are constants within each individual layer, but they vary from layer to layer.