Indentation Curve Analysis for Pile-up, Sink-in and Tip-Blunting Effects in Sharp Indentations

2003 ◽  
Vol 795 ◽  
Author(s):  
Yeol Choi ◽  
Baik-Woo Lee ◽  
Ho-Seung Lee ◽  
Dongil Kwon
Keyword(s):  
Finite Element ◽  
Material Constant ◽  
Indentation Load ◽  
Curve Analysis ◽  
Analysis Method ◽  
Indentation Curve ◽  
Element Simulation ◽  
Maximum Indentation Depth ◽  
Pile Up ◽  
Loading And Unloading

ABSTRACTHardness and elastic modulus can be derived from instrumented sharp indentation curves by considering the effects of materials pile-up and sink-in and tip blunting. In particular, this study quantifies pile-up or sink-in effects in determining contact area based on indentation-curve analysis. Two approaches, finite-element simulation and theoretical modeling, were used to describe the detailed contact morphologies. The ratio of contact depth to maximum indentation depth was proposed as a key indentation parameter and was found to be a material constant independent of indentation load. In addition, this parameter can be determined strictly in terms of indentation-curve parameters, such as loading and unloading slopes at maximum depth and indentation energy ratio. This curve-analysis method was verified by finite-element simulations and nanoindentation experiments.

Analysis of sharp-tip-indentation load–depth curve for contact area determination taking into account pile-up and sink-in effects

2004 ◽  
Vol 19 (11) ◽  
pp. 3307-3315 ◽  
Author(s):  
Yeol Choi ◽  
Ho-Seung Lee ◽  
Dongil Kwon
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Contact Area ◽  
Indentation Depth ◽  
Indentation Load ◽  
Real Contact Area ◽  
Elastic Deflection ◽  
Contact Depth ◽  
Real Contact ◽  
Pile Up

Hardness and elastic modulus of micromaterials can be evaluated by analyzing instrumented sharp-tip-indentation load–depth curves. The present study quantified the effects of tip-blunting and pile-up or sink-in on the contact area by analyzing indentation curves. Finite-element simulation and theoretical modeling were used to describe the detailed contact morphologies. The ratio f of contact depth, i.e., the depth including elastic deflection and pile-up and sink-in, to maximum indentation depth, i.e., the depth measured only by depth sensing, ignoring elastic deflection and pile-up and sink-in, was proposed as a key indentation parameter in evaluating real contact depth during indentation. This ratio can be determined strictly in terms of indentation-curve parameters, such as loading and unloading slopes at maximum depth and the ratio of elastic indentation energy to total indentation energy. In addition, the value of f was found to be independent of indentation depth, and furthermore the real contact area can be determined and hardness and elastic modulus can be evaluated from f. This curve-analysis method was verified in finite-element simulations and nanoindentation experiments.

The Damage of Gas Explosion on the Structure

2013 ◽  
Vol 405-408 ◽  
pp. 684-687 ◽  
Author(s):  
Qin Li
Keyword(s):  
Finite Element ◽  
Natural Gas ◽  
Sharp Increase ◽  
Simulation Analysis ◽  
Daily Life ◽  
Paper Analysis ◽  
Living Standard ◽  
Analysis Method ◽  
Gas Explosion ◽  
Element Simulation

With the development of science and technology and the improvement of people's living standard, Natural gas has been widely applied to daily life. But the sharp increase in natural gas explosion accident. In this paper, Analysis of the effects of gas explosion on the structure, and the safety of the structure was evaluated. By detecting the damage phenomena of gas explosion in a civil building, use the characteristics and law of the gas explosion and finite element simulation analysis method.

Nanomechanical Response of Materials and Thin Film Systems: Finite Element Simulation

1994 ◽  
Vol 356 ◽  
Author(s):  
S.A. Syed Asif ◽  
B. Derby ◽  
S.G. Roberts
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Finite Element ◽  
Finite Element Simulation ◽  
Contact Area ◽  
Considerable Error ◽  
Element Simulation ◽  
Pile Up ◽  
Simulation Results ◽  
Hardness Response

AbstractFinite element simulation of the nanoindentation process has been carried out to investigate the nanomechanical response of materials and thin film systems. The influence of the geometry of the indenter, friction between the indenter and the surface, and pre-stress in the film, on the nanomechanical response have all been investigated. The effect of pile-up on the contact area calculation and the problems which occur with the commonly used methods in calculating the contact area have been studied. Results shows considerable error in calculating the contact area which depends on the indentation conditions used for the simulation. Simulation results suggest, that the influence of residual stress on hardness response is material sensitive.

Study of Nanoindentation Using FEM Atomic Model

2004 ◽  
Author(s):  
Yeau-Ren Jeng ◽  
Chung-Ming Tan
Keyword(s):  
Thin Film ◽  
Finite Element ◽  
Computation Time ◽  
Nonlinear Finite Element ◽  
Atomic Scale ◽  
Scale Model ◽  
Stress And Strain ◽  
Element Formulation ◽  
Element Simulation ◽  
Maximum Indentation Depth

This paper adopts an atomic-scale model based on the nonlinear finite element formulation to analyze the stress and strain induced in a very thin film during the nanoindentation process. The deformation evolution during the nanoindentation process is evaluated using the quasi-static method, thereby greatly reducing the required computation time. The finite element simulation results indicate that the microscopic plastic deformation in the thin film is caused by instability of its crystalline structure, and that the magnitude of the nanohardness varies with the maximum indentation depth and the geometry of the indenter.

Influences of pileup on the measurement of mechanical properties by load and depth sensing indentation techniques

1998 ◽  
Vol 13 (4) ◽  
pp. 1049-1058 ◽  
Author(s):  
A. Bolshakov ◽  
G. M. Pharr
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Indentation Load ◽  
Depth Sensing ◽  
Element Mesh ◽  
Plastic Materials ◽  
Element Simulation ◽  
Load Displacement ◽  
Elastic Plastic Materials ◽  
True Contact

Finite element simulation of conical indentation of a wide variety of elastic-plastic materials has been used to investigate the influences of pileup on the accuracy with which hardness and elastic modulus can be measured by load and depth-sensing indentation techniques. The key parameter in the investigation is the contact area, which can be determined from the finite element results either by applying standard analysis procedures to the simulated indentation load-displacement data, as would be done in an experiment, or more directly, by examination of the contact profiles in the finite element mesh. Depending on the pileup behavior of the material, these two areas may be very different. When pileup is large, the areas deduced from analyses of the load-displacement curves underestimate the true contact areas by as much as 60%. This, in turn, leads to overestimations of the hardness and elastic modulus. The conditions under which the errors are significant are identified, and it is shown how parameters measured from the indentation load-displacement data can be used to identify when pileup is an important factor.

Finite Element Analysis of Slider in High-Speed Horizontal NC Center

2011 ◽  
Vol 225-226 ◽  
pp. 43-46 ◽  
Author(s):  
Ming Cong ◽  
Tao Han ◽  
Qiang Zhao ◽  
Tie Jun Lan ◽  
Xiu Yong Ju
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
High Speed ◽  
Simulation Analysis ◽  
The Other ◽  
Analysis Method ◽  
Great Role ◽  
Original Design ◽  
Element Analysis ◽  
Element Simulation

Slider is one of the most important parts in High-Speed Horizontal Machining NC center, it plays a great role in the performance of static and dynamic. In order to assure the working accuracy and dynamic characters, slider must be analyzed to verify the reasonable of original design. According to the structure of slider and based on the theoretical and finite element simulation analysis method, a more reasonable boundary condition is carried out. To be noted that in this paper a method using the conception of combination is introduced. On the other hand the counterforce can be more accurate than before and it makes the following analysis easier.

Simulation Of Thermal Stresses, Voids And Fracture At The GaAs/Ceramic Interface

1995 ◽  
Vol 409 ◽  
Author(s):  
Nickolaos Strifas ◽  
Aris Christou
Keyword(s):  
Finite Element ◽  
Thermal Management ◽  
Thermal Stresses ◽  
Temperature Cycling ◽  
Analysis Method ◽  
Element Analysis ◽  
Temperature Changes ◽  
Die Attach ◽  
Element Simulation ◽  
Reliable Performance

AbstractStresses induced at the GaAs-Al2O3 interface by large ΔT excursions have been investigated by finite element simulation and have been correlated with experimental results. The effects of power and temperature cycling on crack propagation at the die attach are investigated. The FEA (finite element analysis) method is used to simulate the effect of die attach voids on the peak surface temperature and on the die stresses. These voids in the die attach are identified to be the major cause of die cracking. It was found that stresses developed on the die because of the environmental temperature changes and their dissipation as part of an effective thermal management is necessary to ensure reliable performance.

Indentation load–displacement curve, plastic deformation, and energy

2002 ◽  
Vol 17 (2) ◽  
pp. 502-511 ◽  
Author(s):  
J. Malzbender ◽  
G. de With
Keyword(s):  
Experimental Data ◽  
Plastic Deformation ◽  
Finite Element ◽  
Indentation Load ◽  
Analytical Models ◽  
Dissipated Energy ◽  
Displacement Curve ◽  
Pile Up ◽  
Analytic Expressions ◽  
Hardening Coefficient

Various methods to access indentation data are considered on the basis of the load P–displacement h curve, its derivative, or its integral. This paper discusses and extends the various analytical models to estimate the indentation P–h curve, the slope, and the dissipated energy to aid the development of a concise methodology to analyze indentation data. Special consideration is given to the effect of pile-up and sink-in. Relationships for sharp and spherical indenters are presented and in addition for sharp indenters with a rounded tip. An overview over analytic expressions for the P–h curve is given and compared to finite element simulations and experimental data. An expression derived for the representative strain at the onset of yield under sharp and spherical indenters compares well with literature results. The effect of a rounded tip on the yielding under a sharp indenter is discussed. The ratio of loading to unloading slope and the ratio of the plastically dissipated energy to the total energy is related to hardness and elastic modulus. In combination these ratios can be used to determine the strain-hardening coefficient.

Finite Element Simulation of Indentation Behavior of thin Films

1991 ◽  
Vol 239 ◽  
Author(s):  
D. T. Madsen ◽  
R. J. Giovinazzo ◽  
J. E. Ritter
Keyword(s):  
Thin Films ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Simulation ◽  
Compliant Coating ◽  
Element Analysis ◽  
Plastic Properties ◽  
Element Simulation ◽  
Pile Up ◽  
Measured Hardness

ABSTRACTNanoindentation experiments are now widely used to study the elastic and plastic properties of thin films. Simulation of these experiments has been performed using finite element analysis. Results show the large influence that pile-up or sink-in behavior have on hardness calculations. Results also show that a compliant substrate significantly affects the measured hardness of a stiffer coating. The measured hardness of a compliant coating is less effected by a stiffer substrate.

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