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.

Determination of Stress-Strain Constitutive Relation of Echelle Grating Al Film by Nanoindentation Test and Simulation

2012 ◽  
Vol 625 ◽  
pp. 312-317 ◽  
Author(s):  
Guang Feng Shi ◽  
Guo Quan Shi ◽  
Lin Sen Song ◽  
Zhi Wei Xu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Hardening ◽  
Yield Stress ◽  
Strain Hardening Exponent ◽  
Stress And Strain ◽  
Stress Strain ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Echelle Grating

For the research on elastic-plastic deformation characteristics of the echelle grating in the mechanical ruling depth range, a series of nanoindentation tests are completed about the deposited Al film of available echelle grating with a Berkovich indenter on a CSM nanoindentation instrument. Then a finite element analysis of the nanoindentation process is studied with an orthogonal experiment method for a series of given parameters containing the yield stress and strain-hardening exponent. The optimum combinations of yield stress and strain-hardening exponent are 200MPa and 0.1, which are got by the objective of the least absolute value of maximum loads deviation between the indentation test and the finite element analysis. Finally the elastic-plastic stress-strain curve of power function of the Al film is represented with the difference analysis from the orthogonal simulations.

On Determining Elastic Modulus from Instrumented Indentation

2013 ◽  
Vol 668 ◽  
pp. 616-620
Author(s):  
Shuai Huang ◽  
Huang Yuan
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Plastic Material ◽  
Instrumented Indentation ◽  
Computational Simulations ◽  
Elastic Plastic ◽  
Modified Method ◽  
Plastic Materials ◽  
Elastic Plastic Material ◽  
Elastic Plastic Materials

Computational simulations of indentations in elastic-plastic materials showed overestimate in determining elastic modulus using the Oliver & Pharr’s method. Deviations significantly increase with decreasing material hardening. Based on extensive finite element computations the correlation between elastic-plastic material property and indentation has been carried out. A modified method was introduced for estimating elastic modulus from dimensional analysis associated with indentation data. Experimental verifications confirm that the new method produces more accurate prediction of elastic modulus than the Oliver & Pharr’s method.

The Influence of Imperfections and Nonlinearities on the Failure and B2 Stress Index of Thin-Walled Pipes

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Henry Schau ◽  
Lilit Mkrtchyan ◽  
Michael Geier
Keyword(s):  
Finite Element ◽  
Yield Stress ◽  
Plastic Material ◽  
Limit Load ◽  
Stress Index ◽  
Bending Moments ◽  
Plastic Buckling ◽  
Initial Imperfections ◽  
Thin Walled ◽  
Elastic Plastic Material

The effects of imperfections and nonlinearities on the failure mode and the B2 stress index of thin-walled straight pipes are investigated with finite element (FE) analyses. The analyses were performed for pipes made of an ideal elastic–plastic material and the austenitic steel X6CrNiNb18-10. The B2 index is calculated from the instability bending moments obtained by limit load analyses. The effects of initial imperfections as well as the D/t-ratio and the yield stress on the B2 stress index are studied. As a first result, it is noted that thin-walled straight pipes and imperfections fail due to local plastic buckling. Further analyses show that the type of imperfections, the ovality, the D/t-ratio, and the yield stress have significant influences on the B2 index. The obtained B2 indices for thin-walled straight pipes with D/t > 40 and possible technical imperfections are considerably higher than 1.0. The results have been compared with those of other investigations.

A Finite Element Analysis of Mode III Quasi-Static Crack Growth at a Ductile-Brittle Interface

1996 ◽  
Vol 63 (1) ◽  
pp. 204-209 ◽  
Author(s):  
S. Omprakash ◽  
R. Narasimhan
Keyword(s):  
Finite Element ◽  
Crack Growth ◽  
Power Law ◽  
Plastic Material ◽  
Bimaterial Interface ◽  
Mode Iii ◽  
Elastic Substrate ◽  
Elastic Plastic ◽  
Static Crack ◽  
Elastic Plastic Material

Steady-state quasi-static crack growth along a bimaterial interface is analyzed under Mode III, small-scale yielding conditions using a finite element procedure. The interface is formed by an elastic-plastic material and an elastic substrate. The top elastic-plastic material is assumed to obey the J2 incremental theory of plasticity. It undergoes isotropic hardening with either a bilinear uniaxial response or a power-law response. The results obtained from the full-field numerical analysis compare very well with the analytical asymptotic results obtained by Castan˜eda and Mataga (1991), which forms one of the first studies on this subject. The validity of the separable form for the asymptotic solution assumed in their analysis is investigated. The range of dominance of the asymptotic fields is examined. Field variations are obtained for a power-law hardening elastic-plastic material. It is seen that the stresses are lower for a stiffer substrate. The potential of the bimaterial system to sustain slow stable crack growth along the interface is studied. It is found that the above potential is larger if the elastic substrate is more rigid with respect to the elastic-plastic material.

Finite Element Analysis of Elastic-Plastic Concentrated Contact

2015 ◽  
Vol 662 ◽  
pp. 65-68 ◽  
Author(s):  
Dušan Zíta ◽  
Jaroslav Menčík
Keyword(s):  
Finite Element ◽  
Plastic Material ◽  
Outer Region ◽  
Spherical Body ◽  
Relative Depth ◽  
Depth Of Penetration ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Loading And Unloading ◽  
Elastic Plastic Material

The Paper Shows Results of the Finite Element Modelling of Contact of a Rigid Spherical Body (indenter) with a Body from Elastic-Plastic Material. both the Proces of Loading and Unloading are Modelled. in Addition to Stresses, Also Energies are Investigated, Including their Distribution in the Plastically Deformed Core and the Elastically Deformed Outer Region. Attention is Devoted to Residual Stresses and Energies as well. Influence of Various Factors is Investigated, such as Various Values of Strain-Hardening Parameters (e.g. in Johnson-Cook Model), Relative Depth of Penetration (h/R), Coefficient of Friction.

An Adaptive Pressbrake Control for Strain-Hardening Materials

1986 ◽  
Vol 108 (2) ◽  
pp. 127-132 ◽  
Author(s):  
K. A. Stelson
Keyword(s):  
Strain Hardening ◽  
Material Property ◽  
Plastic Material ◽  
Material Model ◽  
Punch Force ◽  
Elastic Plastic ◽  
The Press ◽  
Elastic Plastic Material ◽  
Thickness Variations ◽  
Force Displacement

An improved adaptive pressbrake control algorithm is described. The problem is to control the punch reversal position of the press so that the final unloaded angle of the bend remains unchanged in the presence of material property and thickness variations of the sheets or plates being bent. Pressbrake control algorithms that use punch force-displacement data to identify thickness and material property variations have shown promise. However, since previous controllers have been based on an elastic-plastic material model, the parts have been overbent. In this paper, a controller based on an elastic, power-law strain-hardening model is proposed. Experiments have shown that the model eliminates the tendency to overbend the parts that is present in the elastic-plastic algorithm.

Finite-Element Solution of Elastic-Plastic Boundary-Value Problems

1981 ◽  
Vol 48 (1) ◽  
pp. 69-74 ◽  
Author(s):  
J. H. Prevost ◽  
T. J. R. Hughes
Keyword(s):  
Finite Element ◽  
Boundary Value Problems ◽  
Plastic Material ◽  
Finite Element Models ◽  
Element Solution ◽  
Elastic Plastic ◽  
Material Stiffness ◽  
Integration Techniques ◽  
Elastic Plastic Material ◽  
Selective Integration

It is demonstrated that elastic-plastic failure states may be captured in finite-element models by employing (1) the elastic-plastic material stiffness to form the global stiffness, (2) reduced/selective integration techniques to alleviate mesh “locking” due to incompressibility, and (3), in the case of symmetrical configurations, an imperfection in the form of a weak element.

Fitness for Service Assessment on Local Metal Loss Near a Discontinuity Using Elastic-Plastic Stress Analysis

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Zhanghai (John) Wang ◽  
Samuel Rodriguez
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Plastic Material ◽  
Material Model ◽  
Metal Loss ◽  
Technical Approach ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Structural Discontinuity ◽  
Elastic Plastic Material

In fitness for service (FFS) assessments, one issue that people often encounter is a corroded area near a structural discontinuity. In this case, the formula-based sections of the FFS standard are incapable of evaluating the component without resorting to finite element analysis (FEA). In this paper, an FEA-based technical approach for evaluating FFS assessments using an elastic-plastic material model and reformed criteria is proposed.

Elastic—plastic finite element analysis of short flat bars with projections part 2: Axial loading

1996 ◽  
Vol 31 (1) ◽  
pp. 25-33 ◽  
Author(s):  
S J Hardy ◽  
M K Pipelzadeh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Plastic Material ◽  
Axial Loading ◽  
Material Model ◽  
Shear Loading ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Elastic Plastic Material ◽  
Stress Concentration Factors

This paper describes the results of a study of the elastic–plastic behaviour of short flat bars with projections subjected to monotonic and cyclic axial loading using finite element analysis. The results are complementary to similar results for (a) shear loading and (b) combined axial and shear loading. Six geometries are considered and elastic–plastic stress and strain data for both local and remote restraints are presented. These geometries and associated restraints result in elastic stress concentration factors in the range 1.69–4.96. A simple bilinear elastic–plastic material model is assumed and the results are normalized with respect to material properties so that they can be applied to geometrically similar components made from other materials which can be represented by the same material models.

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