Progressive damage to structural elements of pipeline systems and efficiency assessment of protection measures

The Aim of this paper is to evaluate the effect of transportation node protection on the resilience of pipeline systems to the development of damage by the mechanism of progressive blocking of nodes as well as the efficiency analysis of the employed protection measures. Damage to a point element of a system due to simultaneous transition into the down state of all the pipelines converging into it is called blocking. The process of progressive blocking of a transportation system’s nodes in a random order is considered to be progressive damage of a network structure. Progressive damage is a hazardous emergency development scenario that is associated with the disconnection of first some, then all end product consumers from the source. A system’s ability to resist progressive damage is estimated by the resilience indicator, the average share of the damaged nodes whose blocking in a random order causes the disconnection of all end product consumers from the source. Methods of research. A system’s indicator of resilience to progressive blocking of nodes was defined using computer simulation. The resilience indicator can only be used in comparative analysis of network structure properties if the analyzed systems are comparable. The condition of comparability of systems with protected point elements is the presence of equal numbers of disconnectable consumer nodes and damageable nodes. If the analyzed systems include protective peripheral clusters that represent interconnected sets of point elements, the following must be equal to enable the comparability of such systems: – number of peripheral clusters with two and more consumer nodes on condition of equal number of such nodes within each system; – most probable order of disconnection from the source of both individual consumers and peripheral clusters with equal numbers of end product consumers. Results. A system’s resilience to progressive blocking can be improved by means of managerial and technical measures of transportation node protection. It has been established that the highest efficiency of protection of individual point elements is achieved in case of protection of a consumer node located at the shortest possible distance from the source of the end product. It is demonstrated that the peripheral cluster for protection of a transportation system should be synthesized by including consumers situated at the minimal possible distance from the source node. Conclusions. The development of emergency situations by the mechanism of progressive blocking of nodes is a hazardous scenario of pipeline system damage. The resilience of a network structure to damage can be improved by means of measures of transportation system nodes protection. The highest efficiency of protection of individual point elements is achieved in case of protection of a consumer node located at the shortest possible distance from the source of the end product. The peripheral cluster for protection of a transportation system from progressive damage should be synthesized by including consumers situated at the minimal possible distance from the source node.