Analysis of buckle propagation in marine pipelines

Abstract

Abstract This paper shows how the analysis of minimum, quasi-static, buckle propagation pressures for subsea pipelines may be exactly formulated in terms of the characteristics of ring collapse. A simple mechanistic approach to ring collapse is described which enables the rational incorporation of the effects of material strain hardening. Theoretical predictions resulting from this analysis are shown to reproduce past empirically observed propagation pressures; they also successfully predict the variations in the forms of ring collapse modes resulting from differing strain-hardening properties. Upon suitable non-dimensionalisation this analysis shows how predicted propagation pressures may be represented in terms of just one composite material and geometric ‘propagation parameter’. This eliminates the need for recourse to empirically fitted design curves and allows resolution of certain anomalies experienced in past analyses. It emphasises the need for more complete information regarding material strain-hardening properties if test results are to be properly interpreted. Most importantly, the present analysis offers the potential for future design of pipelines being at once more rationally and parametrically complete, and yet compact and simple to apply.