Methods for Collapse Pressure Prediction of UOE Linepipe

Abstract

Line pipe intended for deep water applications has to be designed predominantly with regard to external pressure in order to avoid plastic collapse. As a consequence of cold forming during UOE pipe manufacture and the subsequent application of anticorrosion coating, the characteristic stress strain behavior has to be taken into account for a reliable prediction of the collapse pressure. Verification of collapse resistance of large diameter pipes against external pressure requires adequate and reliable component testing using a sufficient number of pipe samples. These samples have to be subjected to test conditions, which closely simulate the situation in service. As the test results may depend significantly on its boundary conditions, the results needs to be thoroughly analysed and compared with existing prediction methods. It is for these reasons that such full-scale testing is time-consuming and costly. The work presented in this paper aims at clarifying and quantifying the effect of existing test boundary conditions on the results of collapse tests (collapse pressures). Correlations will be established between material properties found in laboratory tests and associated component behavior. In this context it had been necessary to develop an accurate and reproducible compression test method. The actual collapse pressures and those predicted using current available equations are compared and verified by Finite Element calculations. The paper concludes with a discussion of the major findings and with a brief outlook to future research issues.

A Review of External Pressure Testing Techniques for Shells including a Novel Volume-Control Method

“…Refs. [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56]. Figure 2(a) shows an open-ended pressure chamber, whereby the end-closure is designed to be directly attached to the specimen.…”