scholarly journals Shear-strain and shear-stress fluctuations in generalized Gaussian ensemble simulations of isotropic elastic networks

2015 ◽  
Vol 88 (9) ◽  
Author(s):  
Joachim Paul Wittmer ◽  
Ivan Kriuchevskyi ◽  
Joerg Baschnagel ◽  
Hong Xu
2021 ◽  
Vol 2 (1) ◽  
pp. 174-194
Author(s):  
Luís Bernardo ◽  
Saffana Sadieh

In previous studies, a smeared truss model based on a refinement of the rotating-angle softened truss model (RA-STM) was proposed to predict the full response of structural concrete panel elements under in-plane monotonic loading. This model, called the “efficient RA-STM procedure”, was validated against the experimental results of reinforced and prestressed concrete panels, steel fiber concrete panels, and reinforced concrete panels externally strengthened with fiber-reinforced polymers. The model incorporates equilibrium and compatibility equations, as well as appropriate smeared constitutive laws of the materials. Besides, it incorporates an efficient algorithm for the calculation procedure to compute the solution points without using the classical trial-and-error technique, providing high numerical efficiency and stability. In this study, the efficient RA-STM procedure is adapted and checked against some experimental data related to reinforced concrete (RC) panels tested under in-plane cyclic shear until failure and found in the literature. Being a monotonic model, the predictions from the model are compared with the experimental envelopes of the hysteretic shear stress–shear strain loops. It is shown that the predictions for the shape (at least until the peak load is reached) and for key shear stresses (namely, cracking, yielding, and maximum shear stresses) of the envelope shear stress–shear strain curves are in reasonably good agreement with the experimental ones. From the obtained results, the efficient RA-STM procedure can be considered as a reliable model to predict some important features of the response of RC panels under cyclic shear, at least for a precheck analysis or predesign.


2013 ◽  
Vol 791-793 ◽  
pp. 362-365
Author(s):  
Li Yang ◽  
Ju Li Li ◽  
Jing Guo Ge ◽  
Meng Li ◽  
Nan Ji

Thermal cycling of a unit Sn0.7Cu solder was studied based on the steady-state creep constitutive equation and Matlab software. The results show that there is a steady-state cycle for the thermal cycling of unit Sn0.7Cu eutectic solder. In steady-state thermal cycling, the shear stress is increased with the increase of temperature. There is a stage of stress relaxation during high temperature. A liner relationship between maximum shear stress and maximum shear strain is observed during thermal cycling. The metastable cycle number is declined greatly with the increase of maximum shear strain.


1974 ◽  
Vol 13 (67) ◽  
pp. 27-35 ◽  
Author(s):  
G. Holdsworth

Examination of the past and present behaviour of the Erebus Glacier tongue over the last 60 years indicates that a major calving from the tongue appears to be imminent. Calculations of the regime of the tongue indicate that bottom melt rates may exceed 1 m a−1. By successive mapping of the ice tongue between the years 1947 and 1970, longitudinal strain-rates were determined using the change in distance between a set of 15 teeth, which are a prominent marginal feature of the tongue. Assuming a flow law for ice of the form where τ is the effective shear stress and is the effective shear strain-rate, values of the exponent n = 3 and B = 1 × 108 N m−2 are determined. These are in fair agreement with published values.


1964 ◽  
Vol 86 (2) ◽  
pp. 157-162 ◽  
Author(s):  
W. K. Luk ◽  
R. C. Brewer

After briefly reviewing previous work in this field, the authors propose that rupture of the chip work contact (to give a discontinuous chip) is governed by a limiting shear strain energy condition. Assuming that shear stress and strain at rupture are dependent on the compressive normal stress, a criterion for the direction of the rupture plane is deduced. Using some results given by Field and Merchant, the authors then compare their calculated direction of rupture with that experimentally observed. Some indication that the agreement is not entirely fortuitous is afforded by checking the calculated shear strain energy at fracture with that calculated from force and chip measurements.


1997 ◽  
Vol 3 (1) ◽  
pp. 61-71 ◽  
Author(s):  
Siyoul Jang ◽  
John A. Tichy

Electro-Rheological (ER) fluid behavior is similar to Bingham fluid’ s. Only when the shear stress magnitude of ER fluid exceeds the yield stress, Newtonian flow results. Continuous shear strain rate equation about shear stress which simulates Bingham-like fluid shows viscosity variations. Shear yield stress is controlled by electric fields. Electric fields in circumferential direction around the journal are also changeable because of gap distance. These values make changes of spring and damping coefficients of journal bearings compared to Newtonian flow case. Implicit viscosity variation effects according to shear strain rates of fluid are included in generalized Reynolds' equation for submerged journal bearing. Fluid film pressure and perturbation pressures are solved using switch function of Elord's algorithm for cavitation boundary condition. Spring and damping coefficients are obtained for several parameters that determine the characteristics of ER fluids under a certain electric field. From these values stability region for simple rotor-bearing system is computed. It is found that there are no big differences in load capacities with the selected electric field parameters at low eccentric region and higher electric field can support more load with stability at low eccentric region.


2007 ◽  
Vol 537-538 ◽  
pp. 541-548 ◽  
Author(s):  
Zoltán Pálmai

The author developed a three-dimensional model for the description of fast plastic deformation of metals in the case of cutting. Shear strain occurring as a result of shear stress has a reverse effect on stress, while the temperature of the material is increasing. These counteracting effects may lead to thermomechanic instability, which may result in aperiodic chaotic conditions besides periodic fluctuation due to the non-linear nature of the process. Apart from bifurcation and multi-cycle periodic deformation, the model also describes aperiodic chaotic deformation, which is proven by experimental results.


2006 ◽  
Vol 519-521 ◽  
pp. 865-870 ◽  
Author(s):  
X.B. Wang

Gradient-dependent plasticity where a characteristic length is involved to consider the microstructural effect (interactions and interplaying among microstructures due to the heterogeneous texture) and the measured nonlinear shear stress-shear strain curves for different loading strain rates are used to calculate the distribution of local temperature rise in adiabatic shear band (ASB) for aluminum-lithium alloy specimen of thin-walled tube in dynamic torsion test. ASB is assumed to initiate just at peak shear stress in the specimen. The temperature rise in ASB is decomposed into the uniform temperature rise in strain-hardening stage and the nonuniform temperature rise in strain-softening stage. The former depends on the measured nonlinear shear stress-shear strain curve prior to the peak, the density, the work to heat conversion factor and the heat capacity. The latter is related to the softening branch of the measured nonlinear shear stress-shear strain curve, the internal length parameter and the physical parameters. For binary Al-Li alloy, the predicted maximum temperatures in ASB are 413K at strain rate of 2000s-1 and 433K at strain rate of 2600s-1. These peak temperatures are lower than the recrystallization and phase transformation temperatures. Higher loading strain rate results in higher pre-peak and post-peak temperature rises, steeper profile of local temperature and higher peak local temperature in ASB. These predictions qualitatively agree with the previously analytical solution for ductile metal exhibiting linear strain-softening behavior beyond the peak shear stress based on gradient-dependent plasticity.


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