Average shear stress yield criterion and its application to plastic collapse analysis of pipelines

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It is known that available analytical and empirical solutions for the burst pressure of defect-free line pipes cannot broadly fit experimental data for different materials. Usually the Tresca prediction provides a lower bound to the burst pressure, and the von Mises prediction provides an upper bound to the burst pressure. A new multiaxial yield criterion, referred to as the average shear stress yield (ASSY) criterion for isotropic hardening materials, is developed in this paper based on the traditional Tresca and von Mises yield criteria so that the burst pressure of a pipeline at plastic collapse can be accurately predicted. As an application of the proposed criterion to the plastic collapse analysis of pipelines, an ASSY-based solution for defect-free line pipes is obtained and formulated as a function of the pipe geometry, the strain hardening exponent and the ultimate tensile stress. Extensive experimental results are then adopted to validate the proposed solutions. Comparisons indicate that (1) the ASSY criterion can well fit the classical experimental data of different ductile metals for both initial and subsequent plastic yielding of a material; and (2) the ASSY-based solution of pipeline burst pressure closely matches the average experimental data for the burst pressure of defect-free pipes for various pipeline steels.