Selection of network structures of pipeline systems resilient to mixed damage

Abstract

Pipeline transportation systems are used for the purpose of delivering to consumers various substances, materials, including those required for continuous flow processes. The operation of such complex industrial facilities is associated with some risks and possible failures of individual units and assemblies due to various causes. The paper examines the specificity of pipeline transportation systems behaviour in emergency situations. The development of such processes may cause the disconnection from the source of some or all end product consumers. The process of damage may occur in accordance with the following mechanisms: progressive damage, when individual pipeline systems fail in a random order; progressive blocking, when individual transportation nodes fail in a random order. An accident scenario, in which progressive damage to linear elements and blocking of transportation nodes simultaneously occur within a system, represents mixed damage. The Aim of this paper is to develop the criteria for estimating a pipeline transportation systems’ resilience to mixed damage, as well as the methods for solving routine problems of synthesis of network structures resilient to such process. Methods of research . The ability of a specific system to resist mixed damage depends on its network structure and is identified by means of simulation. The structural changes caused by mixed damage are described with a cyclogram, whose parameters indicate the number of damaged linear and blocked point elements within one cycle of system exposure. A comparison of the network structures’ ability to resist mixed damage is only possible in case they are comparable. For that purpose, the analyzed systems must have identical numbers of nodes, linear elements, as well as end product consumers. Additionally, such systems must be exposed to mixed damage with identical cyclograms. Results . The simulation of the mixed damage process identified such characteristic as the average percentage of system components, whose failure causes disruption of the connection of all consumers to the source, as well as the average percentage of nodes, whose blocking causes a complete disconnection of the source from all consumers. The developed method of estimation of resilience to mixed damage allows solving the following structural synthesis problems: selection of the position of the source of the end product within the given network; selection of the position of new consumers within an existing system; definition of the locations of additional fragments’ connection to the system; selection of coupling linear elements when additional fragments are connected to a transportation system. Conclusions . Mixed damage is a hazardous development scenario of an emergency situation and is associated with rapid degradation of the transportation capacity of pipeline systems. Various network structures vary in terms of their ability to resist mixed damage, while their resilience characteristics should be identified using computer simulation. A comparison of the mixed damage resilience characteristics is only possible for comparable network structures with equal numbers of nodes, linear elements and end product consumers. Additionally, the same cyclogram of mixed damage must be used.