Accession Number : ADA317988

Title :   Constitutive Equations and Fracture Models for Sea Ice.

Descriptive Note : Final rept. Dec 91-Jun 96,

Corporate Author : TEXAS UNIV AT AUSTIN DEPT OF AEROSPACE ENGINEERING AND ENGINEERING MECHANICS

Personal Author(s) : Rodin, G. J. ; Schapery, R. A.

PDF Url : ADA317988

Report Date : 1996

Pagination or Media Count : 12

Abstract : 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.

Descriptors :   *VISCOELASTICITY, *FRACTURE(MECHANICS), *SEA ICE, MATHEMATICAL MODELS, STRESS ANALYSIS, TIME DEPENDENCE, DEFORMATION, SINGLE CRYSTALS, ICE MECHANICS, CRACK PROPAGATION, CREEP, NONEQUILIBRIUM FLOW, MICROMECHANICS, GRAIN BOUNDARIES, POLYCRYSTALLINE.

Subject Categories : Snow, Ice and Permafrost
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE