Kinematic-Hardening in Zinc-Alloy Tubes

1965 ◽  
Vol 32 (4) ◽  
pp. 849-858 ◽  
Author(s):  
D. R. Jenkins
Keyword(s):  
Strain Hardening ◽  
Kinematic Hardening ◽  
Piecewise Linear ◽  
Stress Path ◽  
Zinc Alloy ◽  
Surface Motion ◽  
Kinematic Theory ◽  
State Of Stress ◽  
Hardening Theory ◽  
Tubular Specimens

The kinematic theory of strain-hardening is used to evaluate the post-yield behavior of tubular specimens subjected to axial force combined with internal pressure or torque. Prediction of yield-surface motion during strain-hardening is simplified through the use of piecewise linear yield criteria. The predicted behavior is compared with the results of experiments on tubes of Zamak-3 zinc alloy. After an initial loading beyond initial yield, the tubes were reloaded along a second stress path to subsequent yield. The observed state of stress at subsequent yield agreed rather well with the kinematic-hardening theory predictions.

Anisotropic Loading Functions for Combined Stresses in the Plastic Range

1955 ◽  
Vol 22 (1) ◽  
pp. 77-85
Author(s):  
L. W. Hu ◽  
Joseph Marin
Keyword(s):  
Plastic Flow ◽  
Biaxial Tension ◽  
Strain History ◽  
Test Results ◽  
Axial Tension ◽  
State Of Stress ◽  
Loading Function ◽  
Combined Stresses ◽  
Shift Of Origin ◽  
Tubular Specimens

Abstract A loading function is a relation between combined stresses for which the beginning of plastic flow takes place. The loading function for a given material is different depending upon the initial plastic strains produced. That is, the initial stress or strain history influences the subsequent loading function. This paper gives the results of an experimental investigation to determine the validity of certain loading functions proposed for anisotropic materials. The study reported was conducted for an aluminum alloy 24S-T and the state of stress covered was biaxial tension. These stresses were produced in the usual way by subjecting thin-walled tubular specimens to axial tension and internal pressure. The test results showed that none of the existing loading functions is adequate for interpreting the plastic stress-strain relations obtained. Tests also were made to determine the change in the loading function with increase in plastic flow. It was found that the loading function did not remain symmetrical with respect to the original function, nor was the new loading function the same as the original except for a shift of origin. However, the test results support in a qualitative way the concept of the so-called “yield corner.”

Cyclic Loading of Beams Based on Kinematics Hardening Behavior Coupled With Isotropic Damage

2006 ◽  
Author(s):  
Ali Nayebi ◽  
Kourosh H. Shirazi
Keyword(s):  
Cyclic Loading ◽  
Strain Hardening ◽  
Kinematic Hardening ◽  
Damage Model ◽  
Mapping Algorithm ◽  
Return Mapping ◽  
Tension And Compression ◽  
Computational Aspects ◽  
Isotropic Damage ◽  
Path Dependent

The kinematic hardening theory of plasticity based on the Prager model and incremental isotropic damage is used to evaluate the cyclic loading behavior of a beam under the axial, bending, and thermal loads. This allows damage to be path-dependent. The damage and inelastic deformation are incorporated and they are used for the analysis of the beam. The beam material is assumed to follow linear strain hardening property coupled with isotropic damage. The material strain hardening curves in tension and compression are assumed to be both identical for the isotropic material. Computational aspects of rate independent model is discussed and the constitutive equation of the rate independent plasticity coupled with the damage model are decomposed into the elastic, plastic and damage parts. Return Mapping Algorithm method is used for the correction of the elastoplastic state and for the damage model the algorithm is used according to the governed damage constitutive relation. The effect of the damage phenomenon coupled with the elastoplastic kinematic hardening is studied for deformation and load control loadings.

Strain Hardening of Annealed 304 Stainless Steel by Creep

1993 ◽  
Vol 115 (4) ◽  
pp. 345-350 ◽  
Author(s):  
Han-Chin Wu ◽  
Chin-Cheng Ho
Keyword(s):  
Stainless Steel ◽  
Strain Hardening ◽  
Kinematic Hardening ◽  
Constant Strain Rate ◽  
Transient Creep ◽  
304 Stainless Steel ◽  
Isotropic Hardening ◽  
Loading Surface ◽  
Before And After ◽  
Strain Hardening Behavior

Combined axial-torsional experiments have been conducted at room temperature on thin-walled tubes to investigate the strain hardening behavior of annealed 304 stainless steel due to creep. The constant strain-rate dynamic loading (or SCISR) surfaces representing the state of material before and after creep have benn determined. It has been found that transient creep essentially causes the loading surface to undergo kinematic hardening with insignificant amount of isotropic hardening for this material. A conclusion is drawn that the loading surface hardened by transient creep is the same as that hardened by plastic deformation. This is true both for specimens with pure tension and pure torsion loading paths. The results confirm assumptions of the overstress theory of viscoplasticity.

scholarly journals Effect of Strain Hardening on Elastic-Plastic Contact of a Deformable Sphere against a Rigid Flat under Full Stick Contact Condition

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Biplab Chatterjee ◽  
Prasanta Sahoo
Keyword(s):  
Strain Hardening ◽  
Kinematic Hardening ◽  
Contact Condition ◽  
Isotropic Hardening ◽  
Contact Conditions ◽  
Elastic Plastic ◽  
Finite Element Software ◽  
Hardening Models ◽  
Load Carrying ◽  
Contact Parameters

The present study considers the effect of strain hardening on elastic-plastic contact of a deformable sphere with a rigid flat under full stick contact condition using commercial finite element software ANSYS. Different values of tangent modulus are considered to study the effect of strain hardening. It is found that under a full stick contact condition, strain hardening greatly influences the contact parameters. Comparison has also been made between perfect slip and full stick contact conditions. It is observed that the contact conditions have negligible effect on contact parameters. Studies on isotropic and kinematic hardening models reveal that the material with isotropic hardening has the higher load carrying capacity than that of kinematic hardening particularly for higher strain hardening.

Effect of Strain Hardening on Monotonic and Cyclic Loading Behavior of Plate-Fin Structures with Two Pore Pressures

2014 ◽  
Vol 626 ◽  
pp. 133-138
Author(s):  
Shuhei Banno ◽  
Dai Okumura ◽  
Nobutada Ohno
Keyword(s):  
Cyclic Loading ◽  
Strain Hardening ◽  
Pore Pressure ◽  
Kinematic Hardening ◽  
Unit Cell ◽  
Viscoplastic Material ◽  
Ratcheting Strain ◽  
Pore Pressures ◽  
Special Cases ◽  
Periodic Unit Cell

We perform finite element homogenization (FEH) analysis to investigate the effect of strain hardening on the monotonic and cyclic loading behavior of plate-fin structures with two pore pressures. As a typical base metal of plate-fin structures, 316 stainless steel is considered and assumed to be the viscoplastic material that obeys the Ohno-Wang kinematic hardening rule. The plate-fin structures are assumed to be periodic and subjected to uniaxial monotonic and cyclic loadings in the stacking direction. A periodic unit cell is used for FEH analysis. Results are compared with those based on three special cases derived from Hill’s macrohomogeneity equation. It is found that the mean pore pressure entirely affect the homogenized viscoplastic behavior. It is further found that the differential pore pressure causes the remarkable accumulation of ratcheting strain in the periodic unit cell, although this internal ratcheting gives no effect on macroscopic relations, resulting in providing a closed hysteresis loop for the plate-fin structures.

scholarly journals Study on Mechanical Properties of Gravelly Sand under Different Stress Paths

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Dongjie Zhang ◽  
Fei Luo ◽  
Zhanyuan Zhu ◽  
Jiaming Liu ◽  
Jing Li ◽  
...  
Keyword(s):  
Strain Hardening ◽  
Stress Ratio ◽  
Void Ratio ◽  
Strain Softening ◽  
Triaxial Compression ◽  
Stress Path ◽  
Tibet Plateau ◽  
Shear Tests ◽  
Characteristic Angle ◽  
The Relationship

To investigate the strength and deformation characteristics of gravelly sand on the Qinghai-Tibet Plateau under different stress paths, a series of triaxial shear tests was conducted under confining pressures of 50–400 kPa in four types of stress path conditions of conventional triaxial compression (CTC) (drained and undrained), triaxial compression (TC), and reduced triaxial compression (RTC). We can see from the test results that gravelly sand samples show strain hardening and shear contraction under the CTC (drained), TC, and RTC during the shearing process but exhibit strain softening under the CTC (undrained). To explore the microscopic deformation mechanism of gravelly sand, a characteristic angle θ was defined to reflect the relative movement of soil particles. The relationship between principal stress ratio σ1/σ3 and characteristic angle θ and that between void ratio e and characteristic angle θ were derived. Subsequently, the relationship expression of stress ratio η (q/p) and void ratio e was established, and the trend of void ratio e with the stress path was studied. To describe the strain hardening and strain softening characteristics of gravelly sand in different stress paths, a new dilatancy equation was obtained by introducing the characteristic state stress ratio Mc into the dilatancy equation of the modified Cam-Clay model based on the state-dependent dilatancy theory. Finally, an elastoplastic constitutive model of gravelly sand was established by applying a nonassociate flow rule. All model parameters can be determined by triaxial shear tests under different stress paths, and the comparison results show that the proposed model can well reflect the mechanical behaviors of gravelly sand under different stress paths.

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