Experimental investigation of a circumferential crack in a PMMA cylindrical shell using caustics

• DOI: 10.1016/j.polymertesting.2019.106086
• Publication Date: 2019-08-27T23:00:36Z
• Authors: Wei Liu; Zhongwen Yue; Guoliang Yang
• Keywords: 0203 mechanical engineering; 02 engineering and technology

Abstract In this paper, the optical method of transmitted caustics is extended to study the stress singularity at the tip of a circumferential crack in a PMMA cylindrical shell. First, a new theoretical analysis of light path is presented based on local deformations around the circumferential crack tip and geometry condition of the cylindrical shell. Second, governing equations of transmitted caustics are established, and the effects of material properties, radius of curvature, shell thickness and crack length on the shape and size of caustic patterns are analyzed. Finally, the stress intensity factors in cracked cylindrical shells under axial tension are evaluated using a simple and reliable optical measurement setup. It is shown that the stress intensity factors obtained by using the optical caustics agree well with the already existing theoretical solutions and the numerical results of finite element analysis.