Specificity of the development of the damage process to network structures of pipeline transportation systems

Introduction. Industrial pipeline transportation systems are complex, potentially hazardous engineering facilities that ensure the delivery of specified amounts of a target product to consumers. The development of emergencies associated with the transition to the down state of a certain number of pipelines may result in the disconnection of some or all the product consumers from the source. If the system’s linear elements transition to the down state in a random order, such a change of the network structure is called a progressive damage. A progressive damage is especially hazardous if, in the course of maintenance activities, a part of the system or a set of process pipelines is disconnected.The Aim of the work is to identify the change patterns of pipeline system resilience when affected by progressive damage and to develop practical recommendations for ensuring the resilience of such systems in operation and during maintenance operations.Methods of research. The resilience of systems as the capability to resist progressive damage was evaluated with an indicator that represents the average fraction of pipelines whose transition into the down state causes the disconnection of all consumers from the source of the product. The resilience values were defined by means of computer simulation. The network structure and the nature of the existing intersystem communications were defined using an adjacency matrix.Results. Damage to a transportation network structure is regarded as a result of a two-stage process. At the stage of target transformation, linear elements are purposefully excluded from a full graph-based structure, bringing the network to a certain initial state. At the second stage, the original structure is transformed according to the mechanism of progressive damage. Such approach allows correctly assessing the changes in the resilience of complex network structures and their ability to resist the development of the processes of damage. The paper sets forth calculated characteristics that allow predicting the behaviour of pipeline networks affected by emergencies. The existence of limit network structures is demonstrated that prove to be very vulnerable to the development of progressive damage.Conclusions. As the process of targeted transformation goes on, the ability of newly formed network structures to resist the development of progressive damage progressively diminishes. The lowest level of pipeline system resilience against the development of the process of progressive damage can be observed as the structure of the network nears the limit state. When preparing maintenance activities with scheduled exclusion of a number of linear elements from an active pipeline system, the proximity of the newly built network structure to the limit state should be assessed along with the resilience of the restored system to possible development of progressive damage.