Mode I&II SIFs for semi-elliptical crack in a cylinder wrapped with a composite layer

Pressure vessels or specifically speaking thin-walled cylinders (or thick-walled) are among frequently used equipment in a wide range of industries and their analysis in different working conditions is of a great importance. In this study, fracture parameters for a semielliptical surface crack in a thin-walled cylinder are investigated using Ansys Workbench commercial software. The distribution of SIF along the crack length is determined for a crack in pure cylinder and the results are verified using ASME Code. Next, wrapping the cylinder with a composite layer, the influence of mechanical properties of composite layer and its thickness on the distribution of mode I & II stress intensity factor (SIF) is investigated. The results reveal that using an orthotropic layer as long as its modulus of elasticity perpendicular to the crack face is greater than pure cylinder’s modulus of elasticity, the SIF declines significantly which is conducive to pressure vessel’s remaining life.

Keywords:

Semi-elliptical Surface crack , Stress Intensity Factor , Pressure Vessel , Finite Element Method