Accession Number : ADA132275

Title :   The Emergence and Propagation of a Phase Boundary in an Elastic Bar.

Descriptive Note : Research rept.,

Corporate Author : CALIFORNIA INST OF TECH PASADENA DIV OF ENGINEERING AND APPLIED SCIENCE

Personal Author(s) : Pence,Thomas James

PDF Url : ADA132275

Report Date : Jun 1983

Pagination or Media Count : 127

Abstract : This dissertation is concerned with the dynamical analysis of an elastic bar whose stress-strain relation is not monotonic. Sufficiently large applied loads then require the strain to jump from one ascending branch of the stress-strain curve to another such branch. For a special class of these materials, a nonlinear initial-boundary value problem in one-dimensional elasticity is considered for a semi-infinite bar whose end is subjected to either a monotonically increasing prescribed traction or a monotonically increasing prescribed displacement. If the stress at the end of the bar exceeds the value of the stress at any local maximum of the stress-strain curve a strain discontinuity or phase boundary emerges at the end of the bar and subsequently propagates into the interior. For classically smooth solutions away from the phase boundary, the problem is reducible to a pair of differential-delay equations for the two unknown functions of a single variable. The first of these two functions gives the location of the phase boundary, while the second characterizes the dynamical fields in the high-strain phase of material. Estimates for the various dynamical field quantities are given and a priori conditions are deduced which determine whether the phase boundary eventually becomes the leading disturbance.

Descriptors :   *Boundary value problems, *Stress strain relations, Elastic properties, Nonlinear analysis, Solids, Dynamic loads, Rods, One dimensional, Theses

Subject Categories : Numerical Mathematics
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE