On strain-rate sensitivity and size effect of brittle solids: transition from cooperative phenomena to microcrack nucleation

An idealized brittle microscale system is subjected to dynamic uniaxial tension in the medium-to-high strain-rate range to investigate its mechanical response under constrained spatial and temporal scales. The setup of dynamic simulations is designed to ensure practically identical in-plane stress c...

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Bibliographic Details
Published in:Continuum mechanics and thermodynamics 2013-03, Vol.25 (2-4), p.489-501
Main Author: Mastilovic, Sreten
Format: Article
Language:English
Subjects:
Brittleness
Classical and Continuum Physics
Cracks
Dynamic tests
Dynamical systems
Dynamics
Engineering Thermodynamics
Heat and Mass Transfer
Kinetic energy
Lattices
Load distribution
Loading rate
Mathematical models
Original Article
Physics
Physics and Astronomy
Sensitivity analysis
Solids
Strain
Strain rate
Structural Materials
Tensile strength
Theoretical and Applied Mechanics
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Summary:An idealized brittle microscale system is subjected to dynamic uniaxial tension in the medium-to-high strain-rate range to investigate its mechanical response under constrained spatial and temporal scales. The setup of dynamic simulations is designed to ensure practically identical in-plane stress conditions on a system of continuum particles forming a two-dimensional, geometrically and structurally disordered, lattice. The rate sensitivity of size effects is observed as well as the ordering effect of kinetic energy. A simple phenomenological expression is developed to account for the tensile strength sensitivity of the small-sized brittle systems to the strain-rate and extrinsic size effects, which may serve as a guideline for formulation of constitutive relations in the MEMS design. The representative sample is defined as a square lattice size for which the tensile strength becomes rate-insensitive and an expression is proposed to model its evolution between two asymptotes corresponding to the limiting loading rates. The dynamics of damage accumulation is analyzed as a function of sample size and loading rate.
ISSN:0935-1175
1432-0959
DOI:10.1007/s00161-012-0279-0