scholarly journals Finite-Element-Based Multiple Normal Loading-Unloading of an Elastic-Plastic Spherical Stick Contact

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Biplab Chatterjee ◽  
Prasanta Sahoo
Keyword(s):  
Finite Element ◽  
Strain Hardening ◽  
Tangent Modulus ◽  
Repeated Loading ◽  
Normal Loading ◽  
Elastic Plastic ◽  
Finite Element Software ◽  
Hardening Models ◽  
Hardening Rules ◽  
Contact Parameters

The repeated normal elastic plastic contact problem of a deformable sphere against a rigid flat under full stick contact condition is investigated with a commercial finite element software ANSYS. Emphasis is placed on the effect of strain hardening and hardening model with the maximum interference of load ranging from elastic to fully plastic, which has not yet been reported. Different values of tangent modulus coupled with isotropic and kinematic hardening models are considered to study their influence on contact parameters. Up to ten normal loading-unloading cycles are applied with a maximum interference of 200 times the interference required to initiate yielding. Results for the variation of mean contact pressure, contact load, residual interference, and contact area with the increasing number of loading unloading cycles at high hardening parameter as well as for low tangent modulus with two different hardening models are presented. Results are compared with available finite element simulations and in situ results reported in the literature. It is found that small variation of tangent modulus results in same shakedown behavior and similar interfacial parameters in repeated loading-unloading with both the hardening rules. However at high tangent modulus, the strain hardening and hardening rules have strong influence on contact parameters.

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.

Finite Element Based Unloading of an Elastic Plastic Spherical Stick Contact for Varying Tangent Modulus and Hardening Rule

2013 ◽  
Vol 1 (1) ◽  
pp. 13-32
Author(s):  
Biplab Chatterjee ◽  
Prasanta Sahoo
Keyword(s):  
Finite Element ◽  
Plastic Material ◽  
Kinematic Hardening ◽  
Tangent Modulus ◽  
Isotropic Hardening ◽  
Finite Element Software ◽  
Perfectly Plastic ◽  
Hardening Models ◽  
Qualitative Similarity ◽  
Elastic Perfectly Plastic

Loading-unloading behavior of a deformable sphere with a rigid flat under full stick contact condition is investigated for varying strain hardening. The study considers various tangent modulus using the finite element software ANSYS. Both the bilinear kinematic hardening and isotropic hardening models are considered. Numerical simulation reveals the qualitative similarity between kinematic and isotropic hardening regarding the variation of interfacial parameters during loading-unloading for various tangent modulus. It is found that the material with kinematic hardening dissipates more energy than the material with isotropic hardening during unloading. However for elastic perfectly plastic material, the loading-unloading behavior is insensitive to hardening model.

scholarly journals Relationship Between Rockwell C Hardness and Inelastic Material Constants

2002 ◽  
Vol 124 (2) ◽  
pp. 179-184 ◽  
Author(s):  
Akihiko Hirano ◽  
Masao Sakane ◽  
Naomi Hamada
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Strain Hardening ◽  
Yield Stress ◽  
Plastic Material ◽  
Stress And Strain ◽  
Material Constants ◽  
Elastic Plastic ◽  
Elastic Plastic Material ◽  
Hardening Coefficient

This paper describes the relationship between Rockwell C hardness and elastic-plastic material constants by using finite element analyses. Finite element Rockwell C hardness analyses were carried out to study the effects of friction coefficient and elastic-plastic material constants on the hardness. The friction coefficient and Young’s modulus had no influence on the hardness but the inelastic materials constants, yield stress, and strain hardening coefficient and exponent, had a significant influence on the hardness. A new equation for predicting the hardness was proposed as a function of yield stress and strain hardening coefficient and exponent. The equation evaluated the hardness within a ±5% difference for all the finite element and experimental results. The critical thickness of specimen and critical distance from specimen edge in the hardness testing was also discussed in connection with JIS and ISO standards.

scholarly journals Simulation of Cyclic Loading on Pipe Elbows Using Advanced Plane-Stress Elastoplasticity Models1

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Konstantinos Chatziioannou ◽  
Yuner Huang ◽  
Spyros A. Karamanos
Keyword(s):  
Cyclic Loading ◽  
Large Scale ◽  
Mechanical Response ◽  
Low Cycle Fatigue ◽  
Constitutive Relations ◽  
Cyclic Plasticity ◽  
Integration Scheme ◽  
Repeated Loading ◽  
Finite Element Software ◽  
Hardening Models

Abstract This work investigates the response of industrial steel pipe elbows subjected to severe cyclic loading (e.g., seismic or shutdown/startup conditions), associated with the development of significant inelastic strain amplitudes of alternate sign, which may lead to low-cycle fatigue. To model this response, three cyclic-plasticity hardening models are employed for the numerical analysis of large-scale experiments on elbows reported elsewhere. The constitutive relations of the material model follow the context of von Mises cyclic elasto-plasticity, and the hardening models are implemented in a user subroutine, developed by the authors, which employs a robust numerical integration scheme, and is inserted in a general-purpose finite element software. The three hardening models are evaluated in terms of their ability to predict the strain range at critical locations, and in particular, strain accumulation over the load cycles, a phenomenon called “ratcheting.” The overall good comparison between numerical and experimental results demonstrates that the proposed numerical methodology can be used for simulating accurately the mechanical response of pipe elbows under severe inelastic repeated loading. Finally, this paper highlights some limitations of conventional hardening rules in simulating multi-axial material ratcheting.

Crack Growth Direction Analysis Based on Elastic-Plastic Property of Material

2011 ◽  
Vol 217-218 ◽  
pp. 101-106
Author(s):  
Zhi Ping Yin ◽  
Jiong Zhang ◽  
Jin Guo ◽  
Qi Qing Huang
Keyword(s):  
Finite Element ◽  
Deflection Angle ◽  
Element Model ◽  
Plastic Property ◽  
Maximum Tensile Stress ◽  
Growth Direction ◽  
Crack Deflection ◽  
Cross Sectional ◽  
Elastic Plastic ◽  
Finite Element Software

The finite element software ANSYS was employed to create a finite element model of the cracked wing beam integrated structure, and the stress field of the crack tip was got by the material nonlinearity (elastic-plastic) analysis method. Based on the maximum tensile stress theory criteria, the crack deflection angle was obtained. The crack deflection angles with different geometry parameters (crack length, wed thickness, the height-thickness ratio of the stringer, cross-sectional area, and the location of the stringer) of the wing beam integrated structure were calculated and compared with each other. So the influences of the geometry parameters of the wing beam integrated structure on the crack deflection were studied. The crack deflection angles obtained in elastic analyzing and elastic-plastic analyzing were compared to investigate the effects of the material property on the crack deflection angle.

Settlement Analysis of Foundation Base on Finite Element Method

2012 ◽  
Vol 204-208 ◽  
pp. 670-673
Author(s):  
Xiao Song ◽  
Hui Zhang ◽  
Guang Sheng Xu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Constitutive Model ◽  
Contact Element ◽  
Composite Foundation ◽  
Elastic Plastic ◽  
Finite Element Software ◽  
Foundation Base ◽  
Settlement Analysis ◽  
Surrounding Soil

Composite foundation influence parameters were discussed based on Drucker-prager elastic-plastic constitutive model in this paper. Contact element was adopted to simulate the interaction between pile and surrounding soil. Finite element software-ANSYS was applied to study and analyze the distribution and deformation of foundation.

Multiple Normal Loading-Unloading Cycles of a Spherical Contact Under Stick Contact Condition

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Y. Zait ◽  
V. Zolotarevsky ◽  
Y. Kligerman ◽  
I. Etsion
Keyword(s):  
Finite Element Method ◽  
Contact Condition ◽  
Isotropic Hardening ◽  
Normal Loading ◽  
Hardening Model ◽  
Loading Cycle ◽  
Hardening Models ◽  
Plastic Sphere ◽  
Elastic Shakedown ◽  
Contact Parameters

The multiple normal loading-unloading process of an elastic-plastic sphere by a rigid flat is analyzed using finite element method for stick contact condition and both kinematic and isotropic hardening models. The behavior of the global contact parameters as well as the stress field within the sphere tip is presented for several loading cycles. It was found that under stick contact condition, secondary plastification occurs even after the second loading cycle and that the hardening model used has little effect on the loading-unloading process. The cyclic loading process gradually converges into elastic shakedown.

Elastic-Plastic Finite Element Analysis of Repeated Indentation of a Half-Space by a Rigid Sphere

1993 ◽  
Vol 60 (4) ◽  
pp. 829-841 ◽  
Author(s):  
E. R. Kral ◽  
K. Komvopoulos ◽  
D. B. Bogy
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Strain Hardening ◽  
Half Space ◽  
Contact Pressure ◽  
Peak Load ◽  
Rigid Sphere ◽  
Load Range ◽  
Elastic Plastic ◽  
Residual Displacements

The elastic-plastic contact problem of a rigid sphere indenting a homogeneous halfspace is analyzed with the finite element method. Emphasis is placed on the load range between elastic and fully plastic deformation, which has not yet been fully investigated. The rigid sphere is modeled by contact elements, thus eliminating the need to assume a particular pressure profile. Different elastic properties, with both elastic-perfectly plastic and isotropic strain hardening behaviors, are considered. Up to four complete frictionless load-unload cycles are applied to a peak load of 300 times the load necessary for the initiation of yielding. Results for the contact pressure, surf ace and subsurface stresses, initiation and growth of the plastic zone, and yielding of the half-space during unloading are presented. The effect of residual displacements on the contact pressure during subsequent load cycles is examined. The influence of strain hardening on the loading and residual stresses is analyzed and the consequences for crack initiation are discussed in light of these results. The accumulation of plastic strain in the yielding regions is tracked through the subsequent load cycles as the material approaches a steady-state elastic cycle, and the significance of the loading and residual stresses on the deformation characteristics is interpreted in the context of finite element results.

Numerical analysis of the counter-intuitive dynamic behavior of the elastic-plastic pin-ended beams under impulsive loading with regard to linear hardening effects

2018 ◽  
Vol 232 (24) ◽  
pp. 4588-4600 ◽  
Author(s):  
Mehdi Shams Alizadeh ◽  
Kourosh Heidari Shirazi ◽  
Shapour Moradi ◽  
Hamid Mohammad Sedighi
Keyword(s):  
Finite Element ◽  
Galerkin Method ◽  
Dynamic Behavior ◽  
Structural Parameters ◽  
Time History ◽  
Anomalous Behavior ◽  
Impulsive Loading ◽  
Linear Hardening ◽  
Elastic Plastic ◽  
Finite Element Software

The counter-intuitive behavior where the permanent deflection of elastic-plastic beam come to rest in the opposite direction of the impulsive loading, normally appears and disappears abruptly, in certain small ranges of loading and structural parameters. One of the most important issues in the study of this phenomenon is the determination of the influence of different parameters. This work is aimed to study the effects of hardening in counter-intuitive dynamic behavior of elastic-plastic pin-ended beams under impulsive loading. This has been done by developing the proposed Galerkin numerical model and presenting a novel algorithm. The Galerkin method as well as the commercial finite element code ANSYS/LS-DYNA is applied to study this phenomenon. In order to account for the hardening effects in Galerkin method, a new algorithm is proposed. The time history curves for mid-span of the beam is studied in detail and the region of the occurrence of the counter-intuitive behavior is determined. Furthermore, using the finite element software, energy diagrams of the beam are also derived. It has been found that the counter-intuitive behavior is a phenomenon, which is very sensitive to loading, therefore it may appear with a little change in the amount of loading. The results also show that although both methods predict one continuous region of loading for the occurrence of this phenomenon in elastic-perfectly plastic beams, still there are two continuous distinct regions of loading, when considering the hardening effects, for this phenomenon. In addition, this anomalous behavior would occur in the proper ratios of kinetic to internal energy and when considering the linear hardening effects, the possibility of the occurrence of the counter-intuitive behavior exists in a wider domain of energy ratio.

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