Session: 02-10-01 Collision and Crashworthiness 1

Paper Number: 81221

81221 - Dynamic Analysis of Collision Between Two Floating Bodies Considering Hydrodynamic Loads 

Collision analysis of floating bodies, i.e. ships and fixed and floating offshore installations involve several technical challenges. A common approach is to split the problem into external and internal mechanics. External mechanics deals with with the impact between the striking and struck bodies as rigid objects to obtain the energy to be dissipated by local deformation, whereas internal mechanics focuses on local damage and fracture, adopting either simple rigid-plastic methods or advanced FEA. While this approach is computationally convenient, it neglects the motion of the bodies in internal mechanics analysus, which occurs mainly due to radiation and also incident wave loading.

This paper presents a numerical simulation framework for coupled dynamic analysis of collision between floating bodies considering the hydrodynamic loading. The framework exploits the capabilities of the general purpose FE software Abaqus for applying the hydrodynamic loads in time domain by using a user-defined loading subroutine. The loading subroutine calculates radiation and wave excitation loading (Froud-Krylov and diffraction) for a given wave condition. The required hydrodynamic coefficients and information (response RAOs) for the load subroutine are obtained prior to the FE analysis using the panel code AQWA, which is based on potential flow theory. The load is applied in time domain to both striking and struck body at their center of gravities. In addition, the structural analysis caters for load rate effects using an advanced fracture model called rate-dependent DSSE-HC. The model combines the Hosford-Coulomb fracture model and a localized necking model called DSSE, which considers strain rate, thermal softening, bending induced delaying of necking and non-proportional loading paths, among others. The proposed framework is applied for several basic collision scenarios for demonstration. The results are discussed with respect to striking and struck bodies motion trajectories and resulting structural damage.

Presenting Author: Burak Can Cerik Inha University

Authors:

Burak Can Cerik Inha University
Joonmo Choung Inha University