NICOP - Vertical penetration of an object through broken ice and floating ice plate
Abstract
Ice is one of the most common materials on Earth. Depending on its morphology andmicrostructure, it may behave as an elastic, britt""le, viscoelastic or even as a quasi-liquidmaterial. The sea-ice consists of solid fresh-water ice, liquid salty brine, gas inclusio""n andpossibly some other components, which makes it difficult to describe and to model. The icecan be in the form of small floatin""g pieces known as broken ice, for example behind anicebreaker or in rivers, or can cover a substantial area of water as an ice shee"t or ice cover.Ship behaviour in cold waters with broken ice is a problem we would like to investigate byusing our experience gained in the NICOP project. Even though the speeds of ship sectionsentering and exiting water are small; the loads acting on the ship sections could besignificant. The existing model of water exit should be modified to account for the presenceof floating ice.High-speed entry of a projectile into water through an ice cover and exit from beneath the iceare the problems of our interest as well. We suggest modelling the ice cover as a viscoelasticfluid on the top of compressible water. The projectile approaches the ice at a certain angle.We are concern in particular with the angle at which the projectile leaves the ice and the dropin its speed.We shall investigate the behavior of the ice during impact by an object on it and the effect ofthe ice on the motion of the object after impact. The work will be performed in closecooperation with Prof. K. Maki from the University of Michigan.The research program is subdivided into the following three tasks:Task 1: Entry and exit of an object through broken iceObjective: To generalize the existing models of water entry and exit to the problem of bodyvertical motion through broken ice.Methods: Mathematical modelling with boundary problems solved by asymptotic andnumerical approaches. Comparison with available CFD and experimental results for tailoringnew models and identification of the most important effects.Task 2: Two-dimensional and axisymmetric problems of body impact onto floating ice sheetwithout breaking iceObjective: To estimate bending stresses in a floating ice plate caused by a body impact ontothe plate with account for actual contact region between the ice and the rigid body and crackson the lower surface of the ice sh"eet.Methods of hydroelasticity, multiscale methods, methods of fracture mechanics andnumerical methods of solving boundary problem"s will be used to achieve the objective.Task 3: Two-dimensional and axisymmetric problems of body impact onto ice sheet with icecr"ushing in the impact regionObjective: To employ the ~hydrodynamic model~ of impact onto ice, validate this model,and apply it to p""ractical problems of ice crushing.Methods of lubrication theory and fracture mechanics, phenomenological methods of icecrushing, a"nd numerical methods.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 03, 2017
- Source ID
- N629091712128
Entities
People
- Alex Korobkin
Organizations
- Office of Naval Research
- United States Navy
- University of East Anglia