Stress State of an Orthotropic Electroelastic Medium with an Arbitrarily Oriented Elliptic Crack Under Uniaxial Tension

2021 ◽  
Author(s):  
V. S. Kyryliuk ◽  
O. I. Levchuk
Keyword(s):  
Stress State ◽  
Uniaxial Tension ◽  
Elliptic Crack ◽  
Electroelastic Medium

scholarly journals Efficiency of Plasticity Correction in the Hole-Drilling Residual Stress Measurement

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3396
Author(s):  
Tomáš Návrat ◽  
Dávid Halabuk ◽  
Petr Vosynek
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Uniaxial Tension ◽  
Relative Error ◽  
Computational Simulation ◽  
Equivalent Stress ◽  
Biaxial Stress ◽  
Hole Drilling ◽  
Plane Shear ◽  
Plasticity Effect

This paper focuses on the analysis of the plasticity effect in the measurement of the residual stress by the hole-drilling method. Relaxed strains were evaluated by the computational simulation of the hole-drilling experiment using the finite element method. Errors induced by the yielding were estimated for uniaxial tension, plane shear stress state and equi-biaxial stress state at various magnitudes of residual stress uniformly distributed along the depth. The correction of the plasticity effect in the evaluation of residual stress was realized according to the method proposed by authors from the University in Pisa, which was coded in MATLAB. Results obtained from the MATLAB script were compared to the original input data of the hole-drilling simulation and discussed. The analyses suggested that the plasticity effect is negligible at the ratio of applied equivalent stress to yield stress, being 0.6, and that the correction of the plasticity effect is very successful at the previous ratio, being 0.9. Failing to comply with the condition of the strain gauge rosette orientation according to the principal stresses directions causes an increase in the relative error of corrected stresses only for the case of uniaxial tension. It affects the relative error negligibly for the plane shear and equi-biaxial stress states.

Possibilities for calculating the stress state of rocks during their uniaxial tension and compression

2020 ◽  
Author(s):  
Valerii Seredin ◽  
Aleksey Khrulev ◽  
Sergey Andreiko ◽  
Sergey Galkin
Keyword(s):  
Stress State ◽  
Uniaxial Tension ◽  
Tension And Compression

Constraint and Failure Assessment Diagram Under Biaxial Loading on Semi-Elliptic Surface Cracks

2012 ◽  
Author(s):  
Zhongxian Wang ◽  
Ruifeng Zhang ◽  
Yuh J. Chao ◽  
Poh-Sang Lam
Keyword(s):  
Uniaxial Tension ◽  
Crack Front ◽  
Biaxial Loading ◽  
Pipeline Steel ◽  
Elliptic Surface ◽  
Elliptic Crack ◽  
J Integral ◽  
Near Surface ◽  
Failure Assessment ◽  
Constraint Level

Three-dimensional finite element analysis has been performed for several configurations of the semi-elliptic surface crack in an X100 pipeline steel plate under various biaxial loading conditions. The biaxial loading ratio (λ) is defined as the ratio of loading parallel to the crack face in the plate width direction to the loading perpendicular to the crack. The constraint level and the J-integral along the semi-elliptic crack front were calculated with J-A2 constraint theory in fracture mechanics, in which A2 is considered as the constraint parameter. It was found that λ influences the J values along the crack front. As λ varies from −1 to 0 then to +1, the location of the maximum J has a tendency to move from the deepest point of the crack to a location near the surface as the load increases, especially for a deeper crack. The constraint level (A2) along the crack front behaves similarly to the J-integral. At λ = −1, the value of A2 increases from the near surface to the deepest penetration when the load increases. In the case of uniaxial tension (λ = 0), the A2 values do not vary significantly except near the surface. When the equibiaxial condition is reached (λ = 1), the location of the highest constraint moves to the near surface. However, in this region the higher constraint level is unable to maintain as the load increases (i.e., the peak value of A2 decreases with increasing load). Finally, the failure assessment diagrams (FAD) at the deepest point of the semi-elliptic crack were constructed with the J-A2 fracture theory. The crack stability regions are apparently smaller in the cases of λ = −1 and 2 than those for λ = 0 (uniaxial tension) or λ = 1 (equibiaxial tension).

scholarly journals Hole-Expansion: Sensitivity of Failure Prediction on Plastic Anisotropy Modeling

2021 ◽  
Vol 5 (2) ◽  
pp. 28
Author(s):  
Jinjin Ha ◽  
Yannis P. Korkolis
Keyword(s):  
Stress State ◽  
Uniaxial Tension ◽  
Plane Strain ◽  
Biaxial Tension ◽  
Plastic Anisotropy ◽  
Yield Function ◽  
Hydraulic Press ◽  
Image Correlation ◽  
Hole Expansion ◽  
Plane Strain Tension

The influence of yield function parameters on hole-expansion (HE) predictions are investigated for an anisotropic AA6022-T4 aluminum sheet. The HE experiment is performed in a fully-instrumented double-action hydraulic press with a flat-headed punch. Full strain fields are measured by a stereo-type digital image correlation (DIC) system. The stress state gradually changes from uniaxial to plane-strain tension to biaxial tension in the radial direction. Besides HE, the plastic anisotropy of AA6022-T4 is characterized by uniaxial tension and plane-strain tension experiments. Uniaxial tension is considered as the most important, since it is the stress state along the hoop direction in the hole. For the finite element (FE) simulation, the Yld2000-2d non-quadratic anisotropic yield function is used with two different parameter sets, calibrated by: (1) uniaxial tension only (termed Calib1) and, (2) both uniaxial and plane-strain tension (Calib2). The strain field predictions show a good agreement with the experiments only for Calib2, which takes into account plane-strain as well uniaxial tension. This indicates the importance of biaxial modes, and in particular plane-strain tension, for the adopted yield function to produce accurate HE simulations.

scholarly journals INFLUENCE OF TEST CONDITIONS ON STRENGTH PROPERTIES OF THIN-WALL RUBBER PRODUCTS

2020 ◽  
pp. 78-84
Author(s):  
D. Kudelin ◽  
T. Nesnolovskaya
Keyword(s):  
Stress State ◽  
Uniaxial Tension ◽  
Stress Concentrator ◽  
Strength Properties ◽  
Complex Stress ◽  
Complex Stress State ◽  
Complex Stressed State ◽  
Shear Stresses ◽  
Thin Wall ◽  
Element Analysis

A computer simulation of the loading of the rubber membrane by a spherical indenter is performed using a finite element analysis package. It is shown that in the complex stress state rubber based on crystallize rubber IR are significantly inferior in strength properties as in the absence and in the presence of stress concentrator to rubber based on amorphous rubber SBR, while in uniaxial tension they are superior. It is revealed that in the complex stress state, rubbers based on IR rubber filled with 40 parts by weight of carbon black N339 have low resistance to shear stresses, inferior to SBR and BR vulcanizates, which results in low strength properties of rubbers based on it in comparison with strength characteristics determined under uniaxial tension. An analysis of the strength properties of rubbers in the presence of a stress concentrator shows that in a complex stress state, rubbers based on amorphous SBR rubber have the maximum tear resistance, exceeding IR and BR vulcanizates by this indicator, respectively by ~ 4 and 2 times. Under uniaxial tension, the most important factor is the ability of the material to orientation hardening, due to the regularity of the rubber structure and the presence of reinforcing filler, and in the complex-stressed state, the most important factor is a density of the nodes of the fluctuation mesh from the point of view of strength properties.

Room temperature creep of fine-grained pure Mg: A direct comparison between nanoindentation and uniaxial tension

2009 ◽  
Vol 24 (5) ◽  
pp. 1615-1618 ◽  
Author(s):  
C.L. Wang ◽  
T. Mukai ◽  
T.G. Nieh
Keyword(s):  
Grain Size ◽  
Stress State ◽  
Uniaxial Tension ◽  
Stress Exponent ◽  
Deformation Mechanism ◽  
Room Temperature ◽  
Apparent Stress ◽  
Fine Grained ◽  
Temperature Creep ◽  
Room Temperature Creep

Nanoindentation creep and uniaxial tension were conducted on pure Mg with a grain size of about 2 μm at room temperature and the data were directly compared. Despite the differences in stress state, the two sets of data were found to match remarkably well with each other. An apparent stress exponent value of 4 was obtained and the deformation mechanism was discussed in light of dislocation slips and twinning in anisotropic Mg.

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