Dynamic response and damage mechanism of parallel wire cables under contact explosion

Abstract

With the global threat of terrorism on the rise, the protection of important infrastructure such as cable-stayed bridges from terrorist assaults has become a major concern. In cable-stayed bridge designs, the cables are crucial load-carrying components, and their failure could result in the progressive collapse of the bridge with catastrophic results. However, there is very limited understanding of the blast effects on cables. This paper presents a study on the blast performance of parallel wire cables under contact explosions. Field blast tests were conducted on four identical parallel wire cable specimens with varying charge weights and prestress levels. Arbitrary-Lagrangian-Eulerian (ALE) algorithm is utilized to develop the numerical model in LS-DYNA. The numerical model is then validated and further used to investigate the damage mechanism of the cable under contact explosions. The results indicate that the damage process of cables under contact blasts can be divided into three stages: Compression, divergence, and stretching. The wires arranged in angular points facing the detonation are particularly vulnerable, and high-density polyethylene (HDPE) is prone to be pelted off by explosive pressure. Parametric analyses were carried out to investigate the influences of charge weight and prestressing force on the damage degree of cables. The relationship between the TNT equivalent and the number of fracture wires is derived from the parametric analysis results. Furthermore, the prestress is found to have a considerable impact on the degree of cable damage induced by contact explosions. Taking prestress into account, a damage evaluation method for blast-damaged cables is proposed.