Numerical investigation of ice load under multimode coupled failure model with radial mesh generation strategy
Description
With the development of numerical methods in polar ship design, the complexity of ice load assessment has been markedly reduced. However, the lack of universal ice material models especially for different failure modes poses a major obstacle to precise ice load prediction. Therefore, a mixed-mode cohesive element model is proposed, coupled with an elastoplastic ice bulk model and a radial mesh generation strategy. Firstly, the multiaxial constitutive relationships and temperature dependent failure criteria of cohesive element are derived to simulate the bending or splitting failure of level ice. Then a bilinear elastoplastic ice bulk material model combined with empirical failure criteria is used to simplify the simulation of ice crushing failure mode. Besides, the radial mesh form is adopted to align with the radial and circumferential fracture patterns, thereby avoiding the excessive fracture path prediction caused by cohesive element method. Subsequently, validation analysis of single ice bulk material model and the mixed model are conducted based on pressure-area curves and lighthouse measured data, respectively. Finally, the parametric sensitivity analysis is performed to quantify the respective contributions to the ice load. The results indicate that a smaller inclination angle of the structure and lower collision velocity lead to global bending or splitting failure of level ice, causing higher ice accumulation loads and lower crushing ice loads. Conversely, higher inclination angle, collision velocity and area, representing severe collision scenarios, lead to a larger extent of crushing failure, causing reduced ice accumulation loads and increased crushing ice loads.
Files
Steps to reproduce
Using the vumat subroutine to simulate the cohesive element model of ice. Using the vdload subroutine to simulate the balance of buoyancy and gravity.