Role of the mesoscopic rotation modes of deformation in formation of macroscopic stress–strain curves

2019 ◽  
Author(s):  
Igor Yu. Smolin ◽  
Pavel V. Makarov ◽  
Rustam A. Bakeev
Keyword(s):  
Stress Strain ◽  
Macroscopic Stress

Role of Falx on Brain Stress-Strain Responses

2008 ◽  
pp. 281-297 ◽  
Author(s):  
Narayan Yoganandan ◽  
Jianrong Li ◽  
Jiangyue Zhang ◽  
Frank A. Pintar
Keyword(s):  
Stress Strain ◽  
Strain Responses

The Simulation and Role of Discontinuous Yield Behaviors of Material

2010 ◽  
Vol 163-167 ◽  
pp. 4590-4594
Author(s):  
Shao Wei Hu
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Stress Rate ◽  
Instability Criterion ◽  
Stress Strain ◽  
Dynamic Behaviors ◽  
Jerky Flow ◽  
Thermal Origin

Discontinuous yield of material as Jerky flow was explained. Then, the strain rate sensitivity (SRS) and instability criterion was given out. Some tests were carried out at constant stress rate, so Jerky flow is manifested as a discontinuity in the stress-strain curves in form of strain bursts. Finally, the dynamic behaviors of specimens during instability of thermal origin were simulated with COLSYS software, whose results are good with test ones.

RELAXATION OF SOME TRANSVERSALLY ISOTROPIC ENERGIES AND APPLICATIONS TO SMECTIC A ELASTOMERS

2008 ◽  
Vol 18 (01) ◽  
pp. 1-20 ◽  
Author(s):  
JAMES ADAMS ◽  
SERGIO CONTI ◽  
ANTONIO DESIMONE ◽  
GEORG DOLZMANN
Keyword(s):  
Unit Vector ◽  
Stress Strain ◽  
Isotropic Energy ◽  
Macroscopic Stress ◽  
Smectic A ◽  
Transversally Isotropic

We determine the relaxation of some transversally-isotropic energy densities, i.e. functions W : ℝ3×3 → [0,∞] with the property W(QFR) = W(F) for all Q ∈ SO (3) and all R ∈ SO (3) such that Rn0 = n0, where n0 is a fixed unit vector. One physically relevant example is a model for smectic A elastomers. We discuss the implications of our result for the computation of macroscopic stress–strain curves for this material and compare with experiment.

Derivation of Polycrystal Creep Properties From the Creep Data of Single Crystals

1977 ◽  
Vol 44 (1) ◽  
pp. 73-78 ◽  
Author(s):  
T. H. Lin ◽  
C. L. Yu ◽  
G. J. Weng
Keyword(s):  
Single Crystals ◽  
Creep Deformation ◽  
Tensile Loading ◽  
Present Theory ◽  
Sole Source ◽  
Stress And Strain ◽  
Creep Data ◽  
Stress Strain ◽  
Macroscopic Stress ◽  
Additional Constant

A method developed for calculating the polycrystal stress-strain-time relation from the creep data of single crystals is shown. Slip is considered to be the sole source of creep deformation. This method satisfies, throughout the aggregate, both the condition of equilibrium and that of continuity of displacement as well as the creep characteristics of single crystals. A very large three-dimensional region is assumed to be filled with innumerable identical cubic blocks, each of which consists of 64 cube-shaped crystals of different orientations. This region is assumed to be embedded in an infinite elastic isotropic medium. This infinite medium is subject to a uniform loading. The average stress and strain of a cubic block at the center of the region is taken to represent the macroscopic stress and strain of the polycrystal. This method is self-consistent and considers the heterogeneous interaction effect of the creep deformation of all slid crystals. The macroscopic stress-strain-time relations of the polycrystal were calculated for three tensile loadings, one radial loading, and two nonradial loadings of combined tension and torsion. The numerical results given by the present theory agree well with those predicted by the so-called “Mechanical Equation of State.” The creep strain components calculated by the present theory for the case of a constant tensile loading followed by an additional constant tensile loading are found to be considerably higher than those predicted by von Mises and Tresca’s theories. These results agree well qualitatively with experimental results.

scholarly journals An in situ synchrotron study of the localized B2↔B19′ phase transformation in an Ni–Ti alloy subjected to uniaxial cyclic loading–unloading with incremental strains

2020 ◽  
Vol 53 (2) ◽  
pp. 335-348
Author(s):  
Xiaohui Bian ◽  
Ahmed A. Saleh ◽  
Peter A. Lynch ◽  
Christopher H. J. Davies ◽  
Azdiar A. Gazder ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Cyclic Loading ◽  
Plastic Strain ◽  
Strain Curve ◽  
Transformation Strain ◽  
Gauge Length ◽  
Stress Strain ◽  
Macroscopic Stress ◽  
Residual Strains

High-resolution in situ synchrotron X-ray diffraction was applied to study a cold-drawn and solution-treated 56Ni–44Ti wt% alloy subjected to uniaxial cyclic loading–unloading with incremental strains. The micro-mechanical behaviour associated with the partial and repeated B2↔B19′ phase transformation at the centre of the sample gauge length was studied with respect to the macroscopic stress–strain response. The lattice strains of the (110)B2 and different B19′ grain families are affected by (i) the transformation strain, the load-bearing capacity of both phases and the strain continuity maintained at/near the B2–B19′ interfaces at the centre of the gauge length, and (ii) the extent of transformation along the gauge length. With cycling and incremental strains (i) the elastic lattice strain and plastic strain in the remnant (110)B2 grain family gradually saturate at early cycles, whereas the plastic strain in the B19′ phase continues to increase. This contributes to accumulation of residual strains (degradation in superelasticity), greater non-linearity and change in the shape of the macroscopic stress–strain curve from plateau type to curvilinear elastic. (ii) The initial 〈111〉B2 fibre texture transforms to [120]B19′, [130]B19′, [150]B19′ and [010]B19′ orientations. Further increase in the applied strain with cycling results in the development of [130]B19′, [102]B19′, [102]B19′, [100]B19′ and [100]B19′ orientations.

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