An orthotropic theory of viscoplasticity based on over-stress for thermomechanical deformation and its application to laminated metal-matrix composites
An infinitesimal, orthotropic theory of viscoplasticity based on overstress for both isothermal and thermal loading cases is presented. The theory is based on existing isotropic formulations of the viscoplasticity theory based on overstress. All material constants and functions can be functions of temperature. No influence of temperature history on the asymptotic solutions is modeled. A yield surface and a loading/unloading condition is not used in the theory. Since invariance requirements constrain the orthotropic growth laws for the state variables, a comparatively simple theory is obtained. The theory models creep, relaxation, rate sensitivity, hysteresis, work, hardening, and tension/compression symmetry and can be reduced to the transversely isotropic, cubic symmetric, and isotropic cases. The theory can be specialized for the cases of inelastic incompressibility, invariance of inelastic properties under superimposed pressure, and tension/compression symmetry. The uniaxial behaviors of the thermal theory are investigated for three different materials. The elastic, inelastic, and cyclic behaviors as well as a temperature rate effect of each material are demonstrated and compared for various thermochemical loading conditions. The orthotropic, thermal viscoplasticity theory based on overseas (OTVBO) is specialized for plane stress in a simple laminate theory. The geometric assumptions of the classical laminate theory are maintained but that the orthotropic linear elasticity law is replaced by OTVBO. The laminate theory is intended for thermal analysis of metal matrix composites operating at high temperature under simultaneous mechanical and thermal loadings.
- Research Organization:
- Rensselaer Polytechnic Inst., Troy, NY (USA)
- OSTI ID:
- 5940085
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360603* -- Materials-- Properties
ALLOYS
ALUMINIUM ALLOYS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
ASYMPTOTIC SOLUTIONS
CHALCOGENIDES
COMPOSITE MATERIALS
COMPRESSION
CREEP
DEFORMATION
DIFFERENTIAL EQUATIONS
ELASTICITY
EQUATIONS
HARDENING
HYSTERESIS
INTERMETALLIC COMPOUNDS
LAYERS
MATERIALS
MATHEMATICAL MODELS
MATHEMATICS
MATRIX MATERIALS
MECHANICAL PROPERTIES
NICKEL ALLOYS
NONLINEAR PROBLEMS
NUMERICAL ANALYSIS
OXIDES
OXYGEN COMPOUNDS
PLASTICITY
STRESSES
TEMPERATURE DEPENDENCE
TENSILE PROPERTIES
TIME DEPENDENCE