Accession Number:

ADA263601

Title:

Rapidly Activated Dynamic Phase Transitions in Nonlinear Solids

Descriptive Note:

Final rept. 1 Aug 1989-15 Dec 1992

Corporate Author:

MICHIGAN STATE UNIV EAST LANSING COLL OF ENGINEERING

Personal Author(s):

Report Date:

1993-02-15

Pagination or Media Count:

22.0

Abstract:

This research project has addressed critical issues concerned with the mathematical modeling of phase transitions in solids. Detailed microstructural analysis has enabled us to clarify the role of stress waves in the propagation of phase boundaries. The potential for phase boundary movement to damp out stress waves has been demonstrated for certain classes of material response. Nucleation of new phase domains by highly energetic processes has been successfully modeled and new analytical procedures have been developed for the predictive response of phase transforming media during high energy impact. Conversion of mechanical energy to thermal energy has been studied by means of an extended theory which incorporates temperature effects. The role of these dynamical events on the response of devices at the engineering level points to the utility of a mathematical description capable of capturing cumulative microstructural effects. To this end we have also developed mathematical protocols capable of tracking the evolution of thermomechanical austenite martensite phase variants due to generalized conditions of loading and heating. The associated mathematical model is capable of capturing superelastic response and two-way shape memory in thermoelastic materials. Ohmic heatingconvective cooling is a likely activation mechanism for smart devices utilizing these materials, and our numerical simulations have successfully replicated these processes including a smooth transition from isothermal to adiabatic response as the loading rate is increased in a heat convective environment.

Subject Categories:

  • Physical Chemistry
  • Operations Research
  • Mechanics
  • Thermodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE