Download or read book Constitutive Equations and Fracture Models for Sea Ice written by and published by . This book was released on 1996 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: This final report summarizes research on deformation and fracture models for sea ice. In many cases results are compared with those for freshwater ice. Described first is work on modeling of primary creep for relatively short loading histories, studies on the applicability of linear elastic fracture mechanics to polycrystalline freshwater and sea ice, and finally a study on stress-transmission in polycrystals undergoing grain boundary sliding. Next, emphasis is on characterization of time-dependent deformation behavior of ice from short to very long-time behavior. This behavior requires the use of models that account for broad spectrum viscoelasticity. Linear viscoelasticity theory is used first in order to develop an understanding of how single-crystal creep produces broad-spectrum behavior of polycrystals through the mechanical interaction of single crystals. Guided by these results and then nonequilibrium thermodynamic principles, nonlinear viscoelastic constitutive equations are developed that make direct use of creep compliances predicted from the linear theory of polycrystals. While only theoretical work has been done on this grant, experimental data provided by others have been used to verify some of the predictions. Comparison of theory and experiment appears in some of the publications.

Download or read book Mechanical Behavior of Sea Ice written by Malcolm Mellor and published by . This book was released on 1983 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first part of the report provides an introduction to the mechanics of deformable solids, covering the basic ideas of stress and strain, rheology, equilibrium equations, strain/displacement relations, constitutive equations, and failure criteria. Fracture mechanics and fracture toughness are also reviewed briefly. The second part summarizes available data on the mechanical properties of freshwater ice and saline ice, accounting for the influences of strain rate and loading rate, temperature, porosity, salinity, and grain size. Boundary value problems are not dealt with, but there is discussion of some miscellaneous topics, including thermal strains, behavior of brash ice, and pressure ridges. The report was written as a study text for a NATO Advanced Study Institute on Sea/Ice/Air Interactions, and was intended to be used in conjunction with companion texts on related topics. This report was written during the summer of 1981, and thus does not cover all results which appeared after the end of 1981.

Download or read book Mechanical Behavior of Sea Ice written by Cold Regions Research and Engineering Laboratory (U.S.) and published by . This book was released on 1983 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first part of the report provides an introduction to the mechanics of deformable solids, covering the basic ideas of stress and strain, rheology, equilibrium equations, strain/displacement relations, constitutive equations, and failure criteria. Fracture mechanics and fracture toughness are also reviewed briefly. The second part summarizes available data on the mechanical properties of freshwater ice and saline ice, accounting for the influences of strain rate and loading rate, temperature, porosity, salinity, and grain size. Boundary value problems are not dealt with, but there is discussion of some miscellaneous topics, including thermal strains, behavior of brash ice, and pressure ridges. The report was written as a study text for a NATO Advanced Study Institute on Sea/Ice/Air Interactions, and was intended to be used in conjunction with companion texts on related topics. This report was written during the summer of 1981, and thus does not cover all results which appeared after the end of 1981.

Download or read book IUTAM Symposium on Scaling Laws in Ice Mechanics and Ice Dynamics written by J.P. Dempsey and published by Springer Science & Business Media. This book was released on 2013-04-18 with total page 479 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Volume constitutes the Proceedings of the IUTAM Symposium on 'Scaling Laws in Ice Mechanics and Ice Dynamics', held in Fairbanks, Alaska from 13th to 16th of June 2000. Ice mechanics deals with essentially intact ice: in this discipline, descriptions of the motion and deformation of Arctic/ Antarctic and river/lake ice call for the development of physically based constitutive and fracture models over an enormous range in scale: 0.01 m - 10 km. Ice dynamics, on the other hand, deals with the movement of broken ice: descriptions of an aggregate of ice floes call for accurate modeling of momentum transfer through the sea/ice system, again over an enormous range in scale: 1 km (floe scale) - 500 km (basin scale). For ice mechanics, the emphasis on lab-scale (0.01 - 0.5 m) research con trasts with applications at the scale of order 1 km (ice-structure interaction, icebreaking); many important upscaling questions remain to be explored.

Download or read book Drift Deformation and Fracture of Sea Ice written by Jerome Weiss and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sea ice is a major component of polar environments, especially in the Arctic where it covers the entire Arctic Ocean throughout most of the year. However, in the context of climate change, the Arctic sea ice cover has been declining significantly over the last decades, either in terms of its concentration or thickness. The sea ice cover evolution and climate change are strongly coupled through the albedo positive feedback, thus possibly explaining the Arctic amplification of climate warming. In addition to thermodynamics, sea ice kinematics (drift, deformation) appears as an essential factor in the evolution of the ice cover through a reduction of the average ice age (and consequently of the cover's thickness), or ice export out of the Arctic. This is a first motivation for a better understanding of the kinematical and mechanical processes of sea ice. A more upstream, theoretical motivation is a better understanding of the brittle deformation of geophysical objects across a wide range of scales. Indeed, owing to its very strong kinematics, compared e.g. to the Earth’s crust, an unrivaled kinematical data set is available for sea ice from in situ (e.g. drifting buoys) or satellite observations. Here, we review the recent advances in the understanding of sea ice drift, deformation and fracturing obtained from these data. We focus particularly on the scaling properties in time and scale that characterize these processes, and we emphasize the analogies that can be drawn from the deformation of the Earth’s crust. These scaling properties, which are the signature of long-range elastic interactions within the cover, constrain future developments in the modeling of sea ice mechanics. We also show that kinematical and rheological variables such as average velocity, average strain-rate or strength have significantly changed over the last decades, accompanying and actually accelerating the Arctic sea ice decline.

Download or read book Ice Mechanics for Geophysical and Civil Engineering Applications written by Ryszard Staroszczyk and published by Springer. This book was released on 2018-12-29 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the concepts and tools of ice mechanics, together with examples of their application in the fields of glaciology, climate research and civil engineering in cold regions. It starts with an account of the most important physical properties of sea and polar ice treated as an anisotropic polycrystalline material, and reviews relevant field observations and experimental measurements. The book focuses on theoretical descriptions of the material behaviour of ice in different stress, deformation and deformation-rate regimes on spatial scales ranging from single ice crystals, those typical in civil engineering applications, up to scales of thousands of kilometres, characteristic of large, grounded polar ice caps in Antarctica and Greenland. In addition, it offers a range of numerical formulations based on either discrete (finite-element, finite-difference and smoothed particle hydrodynamics) methods or asymptotic expansion methods, which have been used by geophysicists, theoretical glaciologists and civil engineers to simulate the behaviour of ice in a number of problems of importance to glaciology and civil engineering, and discusses the results of these simulations. The book is intended for scientists, engineers and graduate students interested in mathematical and numerical modelling of a wide variety of geophysical and civil engineering problems involving natural ice.

Download or read book Fracture of Lake and Sea Ice written by Wilford Frank Weeks and published by . This book was released on 1969 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: The increased activity in cold regions has made a thorough understanding of fracture in lake and sea ice quite desirable, inasmuch as this information has application to a number of problems of geophysical as well as engineering importance. This survey starts with a discussion of the structure of ice I and the macro- and microstructure of sea and lake ice as well as their chemistry and phase relations. Recent work on the direct observation of dislocations as well as the formation of cracks in ice is summarized. Formal ice-brine-air models for analyzing variations in ice strength are also reviewed. The results of the different types of tests are discussed and compared (compressive, indentation, direct and ring-tension, small beam flexure and in situ cantilevers and simple beams, shear, and impact). Scale effects are considered as well as the rapid strength deterioration experienced by ice sheets in the spring. Finally, a number of recommendations are made concerning future research in this field. (Author).

Download or read book Sea Ice Mechanics Research written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Sea Ice Mechanics and Arctic Workshop was held in Anchorage, Alaska, April 25-28, 1995. The workshop focused on current state of the practice and future research needs relative to offshore oil and gas facilities, and also reviewed the results of the U.S. Navy's Office of Naval Research (ONR) Sea Ice Mechanics Initiative (SIMI). SIMI was an Office of Naval Research Accelerated Research Initiative (ARI), spanning the years 1991 to 1996. Its goals were to: understand sea ice constitutive laws and fracture mechanics over the full range of geophysical scales; and determine the scaled response to applied external forces and develop physically based constitutive and fracture models.

Download or read book Sea Ice Mechanics Research Progress written by and published by . This book was released on 1997 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: The architecture for a new large scale (5 to 100 km, 1 hour to 1 day) sea ice dynamics model based on an anisotropic constitutive law is presented here. This architecture accounts directly for refrozen lead systems in the pack ice strength (with an anisotropic failure surface) and in the ice thickness distribution (with an oriented thickness distribution). The lower limit (5 km) of the model resolution is controlled by the fracture spacing of old, thicker ice and the maximum lead width. The upper limit of the model resolution (100 km) is controlled by curvature in the lead directions and variations in the lead width. These in turn are controlled by the variations in internal ice stress due to driving forces (winds and currents), which set the time resolution. This architecture features abrupt changes in the failure surface and the associated flow rule that cannot be averaged over a time step. In addition, the principal stress normal to a new lead must be zero as it opens. This model has sub-scale simulations that allow for the inclusion of phenomena such as ridging, rafting, buckling, and fracture on the behavior of the ice. With this new ice constitutive law, it is possible to directly test the ice failure strength, plastic flow rule, and ice thickness distribution. The data most useful for this testing come from ice stress and position buoys together with SAR deformation data. Some data comparisons have already been made.

Download or read book Sea Ice written by Mohammed Shokr and published by John Wiley & Sons. This book was released on 2015-03-16 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sea Ice: Physics and Remote Sensing addresses experiences acquired mainly in Canada by researchers in the fields of ice physics and growth history in relation to its polycrystalline structure as well as ice parameters retrieval from remote sensing observations. The volume describes processes operating at the macro- and microscale (e.g., brine entrapment in sea ice, crystallographic texture of ice types, brine drainage mechanisms, etc.). The information is supported by high-quality photographs of ice thin-sections prepared from cores of different ice types, all obtained by leading experts during field experiments in the 1970s through the 1990s, using photographic cameras and scanning microscopy. In addition, this volume presents techniques to retrieve a suite of sea ice parameters (e.g. ice type, concentration, extent, thickness, surface temperature, surface deformation, etc.) from space-borne and airborne sensor data. The breadth of the material on this subject is designed to appeal to researchers and users of remote sensing data who want to develop quick familiarity with the capabilities of this technology or detailed knowledge about major techniques for retrieval of key ice parameters. Volume highlights include: Detailed crystallographic classification of natural sea ice, the key information from which information about ice growth conditions can be inferred. Many examples are presented with material to support qualitative and quantitative interpretation of the data. Methods developed for revealing microstructural characteristics of sea ice and performing forensic investigations. Data sets on radiative properties and satellite observations of sea ice, its snow cover, and surrounding open water. Methods of retrieval of ice surface features and geophysical parameters from remote sensing observations with a focus on critical issues such as the suitability of different sensors for different tasks and data synergism. Sea Ice: Physics and Remote Sensing is intended for a variety of sea ice audiences interested in different aspects of ice related to physics, geophysics, remote sensing, operational monitoring, mechanics, and cryospheric sciences.

Download or read book Models and Phenomena in Fracture Mechanics written by Leonid I. Slepyan and published by Springer Science & Business Media. This book was released on 2012-11-07 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presenting the most important results, methods, and open questions, this book describes and compares advanced models in fracture mechanics. The author introduces the required mathematical technique, mainly the theory of analytical functions, from scratch.

Download or read book Ice Structure Interaction written by International Union of Theoretical and Applied Mechanics and published by Springer. This book was released on 1991-07 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt: IUTAM-IAHR Symposium on Ice-Structure Interaction Professor Bez Tabarrok, Chairman of the Canadian National Committee (CNC) of the International Union of Theoretical and Applied Mechanics (IUTAM) invited Professor Derek Muggeridge to organize a symposium on ice structure interaction. Dr. Muggeridge readily agreed and prepared a proposal that was endorsed by the CNC and presented to the General Assembly Meeting of IUTAM for their consideration. This Assembly gave its approval and provided the local organizing committee with the names of individuals who were willing to serve on the Scientific Committee. Dr. Muggeridge became chairman of this committee and Dr. Ian Jordaan became co-chairman of this committee as well as chairman of the local organizing committee. The symposium followed the very successful previous meeting, chaired by Professor P. Tryde in Copenhagen, by ten years. Both symposia uti lized Springer-Verlag to publish their proceedings. The Faculty of En gineering and Applied Science at Memorial University of Newfoundland were particul{lXly pleased to host this prestigious symposium as it marked the twentieth anniversary of its Ocean Engineering Research Centre.

Download or read book Ice engineering written by M. G. Katona and published by . This book was released on 1973 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing operational use od ice areas in polar regions has heightened the requirement for improved knowledge and techniques to analyze the behavior of sea ice. Previous studies on elastic behavior are reviewed with emphasis placed on plate analysis. Classical plate theory and the finite element method are compared in analyzing ice plates, with special attention given to sea-ice airfields. Since elastic analysis is not totally representative of actual ice behavior, a general formulation is presented which gives the assumptions and procedures for both viscoelastic and nonlinear domains of sea-ice behavior. A laboratory program is being initiated to determine material properties that are necessary to extend sea-ice analysis into the inelastic range. (Author).

Download or read book Mathematical Modelling of Monotonic and Cyclic Behavior of Polycrystalline Freshwater Ice written by Ahmed Derradji-Aouat and published by . This book was released on 1992 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of the present work is to develop and evaluate a three dimensional mathematical model for fresh water ice. The model serves as a mathematical base that can be extended to include the mechanical behaviour of sea-ice. A series of creep compression tests were carried out on columnar grained S-2 fresh water ice samples. The objective of this experimental work is to investigate the rate of accumulation of the permanent strains generated in ice undergoing creep deformations for non-cracking conditions. New equations for Poisson's ratio for columnar grained ice are proposed. A three dimensional mathematical model for polycrystalline fresh water ice is developed on the basis of analysis of the experimental results obtained in this study as well as experimental results taken from the literature. The model describes the mechanical behaviour of ice subjected to any loading path in the three dimensional stress space, including cyclic loading. The model formulations take into account the observed material non-linearity, time and temperature dependency, plasticity, material anisotropy, stress path dependency, and hysteresis behaviour of ice subjected to cyclic loading. The model is made up of the sum of two sub-models: A Non-cracking model and a Crack-activity model. Upon loading, ice undergoes both elastic and plastic deformations simultaneously. The total strains are presented as the sum of four strain components. A three dimensional visco-plastic constitutive relation is developed on the basis of the concepts of the classical theory of plasticity. However, modifications of the classical theory of plasticity were made so that the theory could be used to model the behaviour of ice and accommodate time, temperature, and material anisotropy in the constitutive equations. A comprehensive evaluation of the proposed mathematical model is conducted to verify the versatility and accuracy of the model in predicting the observed ice behaviour. The model predictions of the results of the monotonic uniaxial and triaxial tests are in excellent agreement with the measured stress strain curves, the cyclic tests, and the creep tests. Additional evaluation of the model includes theoretical predictions of tensile tests and predictions of the effect of stress rate and initial confining pressure on the behaviour of ice. In the light of all these predictions, recommendations for future research are suggested. (Abstract shortened by UMI.).

Download or read book Finite Element Formulation of Viscous Sea Ice Model written by Reddy, Satti Vijaya Bhaskara and published by 1977.. This book was released on 1977 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Constitutive Modeling and Fracture Analysis of Ice written by Khaled Ibrahim Abdel-Tawab and published by . This book was released on 1995 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Johannes Weertman Symposium written by R. J. Arsenault and published by Minerals, Metals, & Materials Society. This book was released on 1996 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume documents the proceedings of the symposium held to honor Professor Johannes Weertman on his 70th birthday. The chapter topics concentrate on research areas in which Prof. Weertman has made numerous notable contributions, including high temperature deformation, fatigue and fracture plastic deformation of ice, and dynamic plasticity.