Numerical simulation of ice impacts on ship hulls in broken ice fields

2019 ◽  
Vol 180 ◽  
pp. 162-174 ◽  
Author(s):  
Jeong-Hwan Kim ◽  
Yooil Kim ◽  
Hyun-Soo Kim ◽  
Seong-Yeob Jeong
2019 ◽  
Vol 182 ◽  
pp. 211-221 ◽  
Author(s):  
Jeong-Hwan Kim ◽  
Yooil Kim ◽  
Hyun-Soo Kim ◽  
Seong-Yeob Jeong

Author(s):  
Ivan Metrikin ◽  
Andrey Borzov ◽  
Raed Lubbad ◽  
Sveinung Løset

Numerical simulation of a floater in ice-infested waters can be performed using a physics engine. This software can dynamically detect contacts and calculate the contact forces in a three-dimensional space among various irregularly shaped bodies, e.g. the floater and the ice floes. Previously, various physics engines were successfully applied to simulate floaters in ice. However, limited attention was paid to the criteria for selecting a particular engine for the simulation of a floater in broken-ice conditions. In this paper, four publicly available physics engines (AgX Multiphysics, Open Dynamics Engine, PhysX and Vortex) are compared in terms of integration performance and contact detection accuracy. These two aspects are assumed to be the most important for simulating a floater in broken ice. Furthermore, the access to code, documentation quality and the level of technical support are evaluated and discussed. The main conclusion is that each physics engine has its own strength and weaknesses and none of the engines is perfect. These strength and weaknesses are revealed and discussed in the paper.


Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 240
Author(s):  
Shi Song ◽  
Moritz Braun ◽  
Bjarne Wiegard ◽  
Hauke Herrnring ◽  
Sören Ehlers

H-adaptivity is an effective tool to introduce local mesh refinement in the FEM-based numerical simulation of crack propagation. The implementation of h-adaptivity could benefit the numerical simulation of fatigue or accidental load scenarios involving large structures, such as ship hulls. Meanwhile, in engineering applications, the element deletion method is frequently used to represent cracks. However, the element deletion method has some drawbacks, such as strong mesh dependency and loss of mass or energy. In order to mitigate this problem, the element splitting method could be applied. In this study, a numerical method called ‘h-adaptive element splitting’ (h-AES) is introduced. The h-AES method is applied in FEM programs by combining h-adaptivity with the element splitting method. Two examples using the h-AES method to simulate cracks in large structures under linear-elastic fracture mechanics scenario are presented. The numerical results are verified against analytical solutions. Based on the examples, the h-AES method is proven to be able to introduce mesh refinement in large-scale numerical models that mostly consist of structured coarse meshes, which is also beneficial to the reduction of computational resources. By employing the h-AES method, very small cracks are well represented in large structures without any deletions of elements.


2013 ◽  
Vol 32 (11) ◽  
pp. 50-58 ◽  
Author(s):  
Shunying Ji ◽  
Zilin Li ◽  
Chunhua Li ◽  
Jie Shang

Author(s):  
Chao Wang ◽  
Xiaohan Hu ◽  
Taiping Tian ◽  
Chunyu Guo ◽  
Chunhui Wang

Author(s):  
Michael Huisman ◽  
Sandro Erceg ◽  
Rüdiger U. Franz von Bock und Polach ◽  
Thomas Rung ◽  
Sören Ehlers

Abstract The increasing activities in arctic sea areas over the last years have led to a rising demand for numerical tools to design and evaluate ice-going ships. Numerical simulation of ship-ice interaction can be a suitable method for engineers to evaluate ship designs in early development phases. We present an efficient method to evaluate local and global loads on ships in level ice at moderate computational effort. The objective of this contribution is the holistic simulation of the icebreaking process along with the hydrodynamic interplay of the broken ice cups with the surrounding level ice and the hull. For this purpose, a free surface flow solver based upon the Lattice Boltzmann method is coupled to an icebreaking model and a contact-dynamic physics engine. Overall, the approach seeks to compute both local loads, acting on the ship hull, as well as the total resistance in ice. The direct simulation approach makes it possible to consider the load contributions of icebreaking and displacement separately and to analyze their contribution to the total resistance more precisely. Simulation results for a tanker in various ice conditions show significant differences in load distribution and can provide valuable information for the designer of ice-going ships.


Author(s):  
Shi Song ◽  
Moritz Braun ◽  
Hauke Herrnring ◽  
Bjarne Wiegard ◽  
Sören Ehlers

H-adaptivity is an effective tool to introduce local mesh refinement in FEM-based numerical simulation of crack propagation. The implementation of h-adaptivity could benefit the numerical simulation of fatigue or accidental load scenarios involving large structures such as ship hulls. In engineering applications, the element deletion method is frequently used to represent cracks. However, the element deletion method has some drawbacks such as strong mesh dependency and loss of mass or energy. In order to mitigate this problem, the element splitting method could be applied. In this study, a numerical method called ‘h-adaptive element splitting’ (h-AES) is introduced. The h-AES method is applied in FEM programs by combining h-adaptivity with the element splitting method. Two examples using the h-AES method to simulate cracks in large structures under linear-elastic fracture mechanics scenario are presented. The numerical results are verified against analytical solutions. Based on the examples, the h-AES method is proven to be able to introduce mesh refinement in large-scale numerical models that consist of structured coarse meshes. By employing the mesh refinement introduced in this paper, very small cracks are well represented in large structures.


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