Collision Characteristics According to Contact Conditions Between Drifting Objects and Fixed Structures in the Coastal Zone

Lee, W.-D.; Lee, S.-Y.; Park, J.-R., and Hwang, T., 2023. Collision characteristics according to contact conditions between drifting objects and fixed structures in the coastal zone. In: Lee, J.L.; Lee, H.; Min, B.I.; Chang, J.-I.; Cho, G.T.; Yoon, J.-S., and Lee, J. (eds.), Multidisciplinary Approaches to Coastal and Marine Management. Journal of Coastal Research, Special Issue No. 116, pp. 21-25. Charlotte (North Carolina), ISSN 0749-0208. When an object drifting due to a tsunami collides with a structure, the collision force varies significantly depending on the magnitude of the earthquake or tsunami, the weight of the drifting object, the collision velocity, and the distance between the drifting object and the structure. In general, the collision force is proportional to the collision velocity and the weight of the drifting object but also dependent on the contact cross-section between the two objects. In this study, LS-DYNA, a computer simulation program specialized in dynamic analysis, was used to analyze the collision characteristics between a drifting object and a structure, focusing on the contact cross-section between the two objects. In this collision analysis, a 20-foot container was used as the drifting object, while a leg of a port crane was used as the fixed structure. The analysis results suggested that a face-to-face collision between the two objects resulted in a collision force up to 89% greater than an edge-to-face collision between the rotated container and the fixed leg of the crane. This study confirmed that the contact cross-section, along with the weight and collision velocity of the drifting object, significantly impact the collision behavior caused by drifting objects due to tsunamis.