| Résumé | Finite elements simulations of indentation loads caused by an ice sheet on a rigid conical offshore structure were carried out using the ANSYS structural commercial code (www.ansys. com). A square level ice sheet (20.0 m x 20.0 m) pushing a 10 m waterline diameter water cone was considered as the engineering application. The interactions between the structure and the ice sheet were modeled using a nonlinear 3-D contact element formulation. The mechanical behaviour of ice (constitutive model for ice) is elastic, while its failure was modeled using a multi surface failure criterion. The latter includes the effects of the strain (loading) rate, temperature, salinity and porosity on the magnitude of ice strength. During the simulations, failed elements (i.e. elements that satisfy the stress conditions of failure criterion) were taken out from the initial geometry of the ice sheet. Therefore, the process and sequence for breaking ice pieced from the original ice sheet were modeled. This was achieved via developing and ANSYS macro (routine) for element death numerical technique. The validation of the numerical model is presented. The validation was achieved by comparing the computed ice loads from the numerical simulations with full-scale ice load measurements obtained form the Kemi-I test cone (Määttänen et al., 1996). In addition to the validation, the results of sensitivity and parametric analyses are presented and discussed. Conclusions and recommendations are provided. |
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