Damage length predictor for high-speed craft

In 1994 the International Maritime Organization adopted the Code of Safety for High-Speed Craft (HSC Code). After two years of use, several shortfalls were found, one being the damage length predictor, which is based on tradi tional steel, mono-hulled vessels. Other damage predictors were developed b ased on historical data, but they do not account for variables such as alum inum or fiberglass construction, transverse members, indenter geometry vari ation, or for the case where the vessel comes to rest on the grounding obje ct. This paper proposes a damage prediction model based on material propert ies, structural layout, grounding object geometry, and vessel speed. The mo del incorporates four grounding mechanisms: plate cutting, plate tearing, c rushing of plate behind transverse members, and transverse member failure. The method is used to determine the resistance energy, compared to the kine tic energy, of the vessel, to determine an effective damage length. Finite- element analysis was used to model the failure of both aluminum and steel t ransverse members with significant differences in the results. It was found that the transverse members provided the majority of the resistance energy in one grounding mechanism and negligible resistance energy in another.