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) : Pence, Thomas J


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a263601.pdf


Report Date : 15 Feb 1993


Pagination or Media Count : 22


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 heating/convective 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.


Descriptors :   *MATHEMATICAL MODELS , *PHASE TRANSFORMATIONS , *SOLIDS , *NONLINEAR SYSTEMS , THERMAL PROPERTIES , SIMULATION , TEMPERATURE , MICROSTRUCTURE , ENVIRONMENTS , MATERIALS , ENERGY , COOLING , DISSIPATION , CONVECTION , TRACKING , RATES , THIN FILMS , ELASTIC PROPERTIES , STRUCTURES , SHAPE , MECHANICAL ENERGY , MARTENSITE , STRESS WAVES , HYSTERESIS , MEDIA , PARTIAL DIFFERENTIAL EQUATIONS , HEATING , RESPONSE , WAVE PROPAGATION , ENGINEERING , BOUNDARIES , HIGH ENERGY , AUSTENITE , COMPOSITE MATERIALS , MODELS , IMPACT , OPTIMIZATION , ACTIVATION , PROPAGATION , CONVERSION


Subject Categories : Physical Chemistry
      Operations Research
      Mechanics
      Thermodynamics


Distribution Statement : APPROVED FOR PUBLIC RELEASE