Prediction and Comparison of Burst Pressure for Line Pipes

Abstract

Accurate prediction of burst pressure in line pipes is critical for their safety design and operation. Different equations for predicting burst pressure of line pipes have been proposed over the years, but broad agreements between the prediction equations did not exist. To this end, the present authors recently developed a new multi-axial plastic yield theory that is referred to as Average Shear Stress Yield (ASSY) theory [6]. Based on this theory, a theoretical closed-form solution for predicting burst pressure was proposed as a function of the pipe diameter, thickness, ultimate tensile stress and strain hardening exponent. The results showed that the ASSY-based burst pressure solution predicts generally the average of experimental data, and gives the best prediction among different models in a comparison of over 100 full-size burst tests for different line pipe geometries and grades. This conclusion is consistent with the observation by Zimmerman et al. [7]. On the other hand, Law at al. [1–3] recently proposed a so-called CIS (cylindrical instability stress) model that can implicitly predict the burst pressure of line pipes, and claimed that the CIS model is the best one for predicting burst pressure. To clarify the argument and to determine a truly accurate prediction equation, this paper will reevaluate the available models of burst pressure using various experimental data used by Law et al. and others. Detailed comparisons and discussions on the predictions of burst pressure with the experimental results are performed.