On ice model validation and calibration strategies for damage as-sessment of structures subjected to impact actions

Abstract

The number of numerical ice models in structural design is growing, and classical Lagrangian finite element formulation is still dominant for numerical simulations. In design of ships and offshore structures, the numerical methods for calculating ice actions and ice action effects resulting from impacts are often calibrated using labora- tory experiments, pilot and full-scale studies. In situa- tions where the design against abnormal ice actions is required, engineering challenges arise because of a nearly complete lack of relevant experimental or full- scale data. Besides, validation and calibration strategies for numerical ice models are also not solidly established. This paper presents ice model validation and calibration strategies for the scenario of a massive sea ice floe im- pact. This strategy has been used in the damage assess- ment of a floating production storage and offloading vessel subjected to ice impacts. In this paper, devoted to validation of the ice model for abnormal ice impact problems, a short description of the ice model and the model input parameters is provided. In order to validate the performance of the model and prove its ability for damage assessment applications, we consider three different aspects (one calibration and two validation aspects). First we perform a calibration against a design global load. In the second step – validation, we consider a non-uniform pressure distribution over the contact area. Finally, we check how accurate the ice model can represent the crushing specific energy of ice under rapid compressive loading within the brittle regime.