Numerical modeling of lead material : Cyclic shear stress-strain relationship in large strain region

2002 ◽  
Vol 2002.2 (0) ◽  
pp. 103-104
Author(s):  
Akihiro MATSUDA
Keyword(s):  
Numerical Modeling ◽  
Shear Stress ◽  
Large Strain ◽  
Stress Strain ◽  
Cyclic Shear ◽  
Strain Relationship

Model for predicting the variation of shear stress in unsaturated soils during strain-softening

2020 ◽  
Author(s):  
Xiuhan Yang ◽  
Sai Vanapalli
Keyword(s):  
Shear Stress ◽  
Large Deformation ◽  
Unsaturated Soils ◽  
Strain Softening ◽  
Strain Curve ◽  
Published Data ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Strain Relationship ◽  
State Stress

Several of the geotechnical structures constructed with unsaturated soils undergo a large deformation prior to reaching failure conditions (e.g. progressive failure of a soil slope). During this process, the shear stress in soils typically increases initially and then reduces with an increase in the shear strain. The prediction of the stress-strain relationship is critical for reasonable interpretation of the mechanical behavior of those geo-structures that undergo large deformation. This paper introduces a model based on the disturbed state concept (DSC) to predict the variation of shear stress in unsaturated soils during strain-softening process under consolidated drained triaxial compression condition. In this model, the apparent stress-strain relationship is formulated as a weighted average of a hyperbolic hardening response extending the pre-peak state stress-strain curve and a linear response extending the critical state stress-strain curve with an assumed disturbance function as the weight. The prediction procedure is described in detail and the proposed model is validated using several sets of published data on unsaturated soils varying from coarse- to fine-grained soils. Finally, a comprehensive error analysis is undertaken based on an index of agreement approach.

Finite element investigation into the torsion test in the range of large strains and deformations

2001 ◽  
Vol 36 (4) ◽  
pp. 401-409
Author(s):  
X Peng ◽  
Y Qin ◽  
R Balendra
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Shear Strain ◽  
Twist Angle ◽  
Large Strains ◽  
End Effect ◽  
Stress Strain ◽  
Strain Relationship ◽  
Thin Walled ◽  
Tubular Specimens

Torsion tests with thin-walled tubular, solid cylindrical and Lindholm-type tubular specimens were simulated using the finite element code ABAQUS, in the range of large strains and deformations. The results showed that for thin-walled tubular and solid cylindrical specimens the radii of the specimens almost remained straight during torsion; for Lindholm-type tubular specimens the twist angle of the cross-section at the two ends of the gauge section did not stay constant, due to the change of the specimen geometry (i.e. the end effect). A correction which considers the end effect should therefore be introduced when the stress-strain relationship is characterized. Compared with the stress-strain relationship obtained previously from experiment, a distinct difference was noted when conventional formulae were used to convert the torque and twist angle into the shear stress and shear strain. Further, the influence of axial constraint conditions at the two ends of the specimen was examined; the results showed that axial strains and stresses had no significant influence on the definition of the shear stress-shear strain relation, and hence these can be neglected when the stress-strain relationship is characterized.

scholarly journals Measurement of Pure Shear Constitutive Relationship from Torsion Tests under Quasi-static, Medium and High Strain Rate Conditions

2021 ◽  
pp. 1-26
Author(s):  
LongHui Zhang ◽  
David Townsend ◽  
Nik Petrinic ◽  
Antonio Pellegrino
Keyword(s):  
Shear Stress ◽  
High Strain Rate ◽  
Strain Rate ◽  
Digital Image ◽  
High Strain ◽  
Pure Shear ◽  
Rate Sensitivity ◽  
Constitutive Relationship ◽  
Stress Strain ◽  
Strain Relationship

Abstract Torsion tests provide important shear stress and shear strain relationships to reveal the fundamental plastic flow response of a material. Bespoke torsion techniques complemented by Digital Image Correlation are developed to accurately measure the shear stress-strain relationship at quasi-static, medium rate 9/s and high strain rate above 1000/s. The equipment used includes a screw driven mechanical system, a hydraulic Instron machine and a Campbell thin-walled tube split Hopkinson torsion bar equipped with an ultra-high speed camera. A near alpha Ti3Al2.5V alloy was used as a model material in this study. A four camera digital image system has been constructed to monitor the material deformation and failure during a low rate torsion test, to gain further insight into plastic deformation of the tubular specimen. Shear stress-strain relationship of the Ti3Al2.5V alloy exhibits noticeable strain rate sensitivity. Observations of the strain hardening rate evolution indicate that the hardening capacity of Ti3Al2.5V is both strain and strain rate dependent. High strain rate torsional stress-strain relationship shows lower strain hardening, compared to the response obtained from a shear compression specimen. The present techniques are demonstrated to be suitable for the measurement of pure shear constitutive relationship, including rate sensitivity and failure of the material.

The KES Shear Test for Fabrics

1997 ◽  
Vol 67 (9) ◽  
pp. 654-664 ◽  
Author(s):  
Jin-Lian Hu ◽  
Yi-Tong Zhang
Keyword(s):  
Shear Stress ◽  
Shear Modulus ◽  
Shear Deformation ◽  
Shear Test ◽  
Pure Shear ◽  
Shear Stresses ◽  
Stress Strain ◽  
Complex Deformation ◽  
Strain Relationship ◽  
Shear Tester

Many fabric mechanics researchers have reported that specimens being tested on the KES shear tester are not subjected to pure shear deformation; therefore, test results cannot lead directly to a determination of the fabric shear modulus and stress/strain relationship, particularly in the nonlinear range of stress-strain. Combined with finite element analysis, this paper presents an analytical solution for the distribution of shear stresses and strains in fabric specimens tested on the kes tester. A fabric is treated as an orthotropic sheet during the analysis, which leads to a closed-form solution for the shear modulus as a function of fabric tensile and shear moduli from the kes shear test. A modified shear stress-strain relationship can also be derived. From calculations for fabrics used here, the difference between modified and tested shear modulus values is about 25–30%. The study also suggests that although the shear modulus and curves obtained on the kes shear tester are significantly different from those under the pure shear state, the kes results can still reflect the nature of a fabric under shear deformation and are valid for general objective evaluations. The exact shear stress-strain relationship and actual shear modulus may be modified only when they are required for fabric complex deformation analysis.

scholarly journals The Effect of Intersection Angle on the Failure Mechanism of Utility Tunnel

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Li Fangtao ◽  
Qiyao Wang ◽  
Zhiping Hu ◽  
Zhang Yonghui ◽  
Ren Xiang ◽  
...  
Keyword(s):  
Shear Stress ◽  
Simulation Method ◽  
Control Measures ◽  
Vertical Shear ◽  
Tension Stress ◽  
Stress Strain ◽  
Intersection Angle ◽  
Ground Fissures ◽  
Strain Relationship ◽  
Utility Tunnel

Planning utility tunnel network in the area with geological disasters poses serious concerns, especial for the utility tunnel built in the ground fissures developed cities. Many prevention and control measures have been taken when the utility tunnel crossed the ground fissures, such as finding the right intersection angle when planning the utility tunnel. In order to study the effect of intersection angle for utility tunnel when crossing ground fissures, this paper compares outcomes when the utility tunnel crosses ground fissures with different intersection angle through numerical simulation method. Because actually the intersection angle of utility tunnel and ground fissures is varied, in order to make stress-strain relationship of the model more realistic, a trilinear mode of reinforcing bar stress-strain relationship was established, and the material property of utility tunnel and soil were assigned to concrete damaged plasticity and Mohr-Coulomb plasticity, respectively. The simulation result shows that the axial tension stress and vertical shear stress of utility tunnel are increased with the increasing of intersection angle, but displacement and shear stress of utility tunnel in horizontal direction are increased with the decreasing of intersection angle. The variation of intersection angle of utility tunnel and ground fissures cannot significantly reduce the damage of utility tunnel. The vertical displacement of utility tunnel does not vary with intersection angle. Finally, this paper suggests that the strengthening length of utility tunnel should not be less than 50 meters (10 times the height of utility tunnel) on both sides of the ground fissures no matter the variation of intersection angle.

Mathematical Model for Shear Stress-Strain Relationship of Soil-Concrete Interface during Shear Fracture Process

2007 ◽  
Vol 348-349 ◽  
pp. 881-884 ◽  
Author(s):  
Wei Wang ◽  
Ting Hao Lu ◽  
Bin Xiang Sun
Keyword(s):  
Shear Stress ◽  
Fracture Process ◽  
Shear Fracture ◽  
Hyperbolic Model ◽  
Stress Strain ◽  
Numerical Studies ◽  
Proposed Model ◽  
Strain Relationship ◽  
Relationship Of ◽  
Concrete Interface

Description of shear stress-strain relationship for soil-concrete interface during shear fracture process plays an important role in experimental and numerical studies of soil-structure interaction. In this paper, deficiency of traditional hyperbolic model for the shear stress-strain relationship is analyzed, firstly. Then, a new model with 3 parameters for it is established, which can overcome the deficiency of hyperbolic model. Finally, good agreements have been found between the proposed model and laboratory tests.

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