Finite Element Analysis of Piping System Under Blast Load Due to Accidental Explosion

Abstract

Abstract This paper presents a methodology for nonlinear dynamic finite element analysis of piping system, which mainly consists of process piping, and pipe supports subjected to accidental blast loading. As opposed to an ASME B31.3 linear elastic static code check performed on Caesar II (Category 1) or a simplified single-degree-of-freedom (SDOF) approach (Category 2), a multi-degree-of-freedom (MDOF) approach is more realistic and less conservative for blast analysis of piping systems. Thus, the piping system is modeled as a multi-degree-of-freedom (MDOF) system to capture both the local and global responses. Furthermore, an in-house scripting tool was developed to automatically convert the piping stress analysis input files (in Caesar II) to blast analysis input files (in Abaqus). The scripting tool allows blast analysis of several hundreds of piping systems to be performed within a competitive project timeline. In the blast analysis model, blast load is applied as drag load on the piping system. In this study, geometric, material, and boundary condition nonlinearities are considered. The blast analysis is performed using commercial finite element software Abaqus/Explicit. The displacements and plastic strains at different locations of the piping system are evaluated and compared against a pre-established displacement limit and a plastic strain limit. Based on the analysis results, the number of additional pipe-supports which were required by linear elastic static or SDOF analysis approaches were significantly reduced along the piping systems.