Due to complex mesoscopic and the distinct macroscopic evolution characteristics of ice,especially for its brittle-to-ductile transition in dynamic response,it is still a challenging task to build an accurate ice cons...Due to complex mesoscopic and the distinct macroscopic evolution characteristics of ice,especially for its brittle-to-ductile transition in dynamic response,it is still a challenging task to build an accurate ice constitutive model to predict ice loads during ship-ice collision.To address this,we incorporate the conventional multi-yield-surface plasticity model with the state-based peridynamics to simulate the stress and crack formation of ice under impact.Additionally,we take into account of the effects of inhomogeneous temperature distribution,strain rate,and pressure sensitivity.By doing so,we can successfully predict material failure of isotropic freshwater ice,iceberg ice,and columnar saline ice.Particularly,the proposed ice constitutive model is validated through several benchmark tests,and proved its applicability to model ice fragmentation under impacts,including drop tower tests and ballistic problems.Our results show that the proposed approach provides good computational performance to simulate ship-ice collision.展开更多
The ice-structure collision is a transient process, which is further complicated by the presence of the water. It remains unclear how important the hydrodynamic influences are during the collision. This problem is par...The ice-structure collision is a transient process, which is further complicated by the presence of the water. It remains unclear how important the hydrodynamic influences are during the collision. This problem is partially investigated in this paper using numerical methods. To simplify the problem as much as possible without loss of generality, a short ice cylinder of circular section is assumed to collide with a vertical large structure plate under a variety of collision scenarios. Among them the most important cases are: (1) the rigid ice cylinder collision with the rigid or elastic structural plate at different collision velocities, (2) the elastic ice cylinder collision with the rigid or elastic structural plate at different collision velocities and (3) the elastoplastic ice cylinder collision with the rigid or elastic structural plate at different collision velocities. The numerical results show that: (1) the hydrodynamic influences are negligible in the first case, (2) the hydrodynamic influences in the second and third cases are not negligible, and become very significant in the third case. The influences are numerically estimated to be in the range of 20%–60% in terms of the momentum change. If the ice response is approximately decomposed into the rigid-body motions and the deformation modes at the instant of the collision with the structure, the previous conclusions show that the hydrodynamic influences on the rigid-body motions of the ice are negligible, but those on the elastic and elastoplastic modes of the ice are significant. Comparison with the case of a submerged ice cylinder (although not a practical case) reveals that the hydrodynamic influences are small in the first case due to the fact that the energy loss is used to produce the water splash and the cavity behind the ice cylinder. Through this study we come into the conclusion that the hydrodynamic influences are not important for the rigid-body motions, but important for the elastic or elastoplastic modes.展开更多
文摘Due to complex mesoscopic and the distinct macroscopic evolution characteristics of ice,especially for its brittle-to-ductile transition in dynamic response,it is still a challenging task to build an accurate ice constitutive model to predict ice loads during ship-ice collision.To address this,we incorporate the conventional multi-yield-surface plasticity model with the state-based peridynamics to simulate the stress and crack formation of ice under impact.Additionally,we take into account of the effects of inhomogeneous temperature distribution,strain rate,and pressure sensitivity.By doing so,we can successfully predict material failure of isotropic freshwater ice,iceberg ice,and columnar saline ice.Particularly,the proposed ice constitutive model is validated through several benchmark tests,and proved its applicability to model ice fragmentation under impacts,including drop tower tests and ballistic problems.Our results show that the proposed approach provides good computational performance to simulate ship-ice collision.
基金supported by the Major Project of National Natural Science Foundation of China(Grant No.52192692)the National Natural Science Foundation of China(Grant No.52171294).
文摘The ice-structure collision is a transient process, which is further complicated by the presence of the water. It remains unclear how important the hydrodynamic influences are during the collision. This problem is partially investigated in this paper using numerical methods. To simplify the problem as much as possible without loss of generality, a short ice cylinder of circular section is assumed to collide with a vertical large structure plate under a variety of collision scenarios. Among them the most important cases are: (1) the rigid ice cylinder collision with the rigid or elastic structural plate at different collision velocities, (2) the elastic ice cylinder collision with the rigid or elastic structural plate at different collision velocities and (3) the elastoplastic ice cylinder collision with the rigid or elastic structural plate at different collision velocities. The numerical results show that: (1) the hydrodynamic influences are negligible in the first case, (2) the hydrodynamic influences in the second and third cases are not negligible, and become very significant in the third case. The influences are numerically estimated to be in the range of 20%–60% in terms of the momentum change. If the ice response is approximately decomposed into the rigid-body motions and the deformation modes at the instant of the collision with the structure, the previous conclusions show that the hydrodynamic influences on the rigid-body motions of the ice are negligible, but those on the elastic and elastoplastic modes of the ice are significant. Comparison with the case of a submerged ice cylinder (although not a practical case) reveals that the hydrodynamic influences are small in the first case due to the fact that the energy loss is used to produce the water splash and the cavity behind the ice cylinder. Through this study we come into the conclusion that the hydrodynamic influences are not important for the rigid-body motions, but important for the elastic or elastoplastic modes.
