ABSTRACT. This work is focused on the numerical implementation of thermo-viscoplastic constitutive equations in small and finite strain contexts using FEM. A length scale parameter is introduced implicitly through viscosity in order to address strain localization in the (initial) boundary value problems. The mathematical structure of the infinitesimal viscoplasticity theory is concise and simil...

The time-independent and time-dependent mechanical behavior of electrochemically lithiated silicon was studied with nanoindentation. As indentation was performed with continuous stiffness measurements during loading and load-hold, new insight into the deformation behavior of lithiated silicon is furnished. Supporting other research, Young's modulus and the hardness of lithiated silicon are foun...

Molecular-dynamics simulations of fracture in metallic glass-like systems are observed to undergo embrittlement due to a small change in interatomic potential. This change in fracture toughness, however, is not accompanied by a corresponding change in flow stress. Theories of brittle fracture proposed by Freund and Hutchinson indicate that strain rate sensitivity is the controling physical para...

here we denote by σ the stress tensor, by ε the linearized strain tensor, by B(x) the compliance tensor and by ∂φ(·, x) the subdifferential of a convex function φ(·, x). This relation accounts for elasto-viscoplasticity, including a nonlinear version of the classical Maxwell model of viscoelasticity and the Prandtl–Reuss model of elastoplasticity. The constitutive law is coupled with the equati...

Dynamic and creep behavior of 80In15Pb5Ag and 50Sn50Pb were studied isothermally over nine decades of time and frequency. 80In15Pb5Ag was examined at 26, 21, and 50 °C, and 50Sn50Pb was examined at 21 °C. Viscoelastic behavior was observed at strains less than 10 as a function of temperature and time/frequency. At the small strain used in the study, the alloys exhibit linear viscoelasticity rat...