Author(s)

N. Jones & R. S. Birch

Abstract

Experimental tests are reported on steel pipelines that have been struck by a relatively large rigid wedge-shaped mass travelling up to 10.4 m/s. A pipeline is supported across a span, is fully clamped at both ends and is struck at the mid-span and at the one quarter span positions. Most of the pipelines are pressurised with a nitrogen gas. The initial impact energy produces large inelastic ductile deformations of the pipeline and, in some cases, failure. The experimental results are compared with previous data obtained on larger diameter pipelines and observations are offered on the accuracy of the geometrically similar scaling of the final deformations. The results are also compared with several empirical equations and comments are made on their accuracy. Keywords: pipelines, impact loading, internal pressure, ductile deformations, failure, empirical equations, geometrically similar scaling. 1 Introduction Pipelines are used throughout industry to convey gases and liquids under high pressures over long distances and between pressure vessels and other industrial plant. These pipelines are often situated in potentially dangerous environments so that safety calculations are required by various bodies to assess the hazards associated with the accidental release of any contents. Impact loads are particularly hazardous and estimates are required for the resistance of a pressurised pipeline to any object that, for example, may be dropped from a crane during maintenance operations, or propelled by the gases after an explosion that causes fragmentation of a pressure vessel. This article focuses on those extreme events when heavy objects travelling at relatively low velocities

Keywords

pipelines, impact loading, internal pressure, ductile deformations, failure, empirical equations, geometrically similar scaling.