On the Failure of Ellipticity and the Emergence of Discontinuous Deformation Gradients in Plane Finite Elastostatics.

Abstract

This investigation concerns equilibrium fields with discontinuous displacements gradients, but continuous displacements, in the theory of finite plane deformations of possibly anisotropic, compressible elastic solids. Elastostatic shocks of this kind, which resemble in many respects gas-dynamical shocks associated with steady flows, are shown to exist only if and when the governing field equations of equilibrium suffer a loss of ellipticity. The local structure of such shocks, near a point on the shock-line, is studied with particular attention to weak shocks, and an example pertaining to a shock of finite strength is explored in detail. Also, necessary and sufficient conditions for the dissipativity of time-dependent equilibrium shocks are established. Finally, the relevance of the analysis carried out here to localized shear failures - such as those involved in the formation of Lueders bands - is discussed. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 1977
Accession Number
ADA042513

Entities

People

  • Eli Sternberg
  • James K. Knowles

Organizations

  • California Institute of Technology

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Boundaries
  • Boundary Value Problems
  • Continuity
  • Discontinuities
  • Elastic Materials
  • Equations
  • Flow
  • Gas Dynamics
  • Hyperelastic Materials
  • Materials
  • Mechanics
  • Military Research
  • Molecular Dynamics
  • Quadratic Equations
  • Shear Modulus
  • Shock
  • Two Dimensional

Readers

  • Combustion Dynamics and Shock Wave Physics.
  • Finite Element Method (FEM) for solving Partial Differential Equations (PDEs)
  • Mechanical Engineering/Mechanics of Materials.