Analysis of Elastic Surface Cracks in Cylinders Using the Line-Spring Model and Shell Finite Element Method

This paper presents elastic analysis of axial and circumferential semielliptical surface flaws in cylinders using the line-spring model of Rice and Levy [1-3] and a shell finite element method. Results for the stress intensity factor are obtained at various points along the crack front, and are compared in some cases against published literature solutions. A broad range of values for the cylinder radius-to-wall thickness ratio, flaw depth and aspect ratio are considered including surface flaws with very large aspect ratios. The critical values of aspect ratio at which the surface flaws can be treated as 2-dimensional cracks are determined. Effect flaw location (internal or external) and flaw shape (semielliptical, circular or rectangular) are also investigated. Finally, the significance of these results in the elastic-plastic fracture analysis procedures is discussed.