scholarly journals Comparative Analysis Carried Out on Modern Indentation Techniques for the Measurement of Mechanical Properties: A Review

2020 ◽  
Author(s):  
Saquib Rouf ◽  
Sobura Altaf ◽  
Shezan Malik ◽  
Kaleem Ahmad Najar
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Comparative Analysis ◽  
Contact Area ◽  
Indirect Method ◽  
Indentation Depth ◽  
Depth Of Penetration ◽  
Simple Method ◽  
Indentation Technique ◽  
Force Contact

Nowadays many indentation techniques are being commonly employed for determining some mechanical properties (harness, elastic modulus, toughness, etc.) using simple method of measuring the indentation depth. On the basis of measurement of depth of penetration, indentation technique has be classified into major categories i.e. microindentation and nanoindentation. Nanoindentation technique uses indirect method of determining the contact area as the depth of penetration is measured in nanometers, while in conventional indentation the area in contact is measured by elementary measurement of the residual area after the indenter is removed from the specimen. Dynamic hardness is the best result of dynamic indentation which can be expressed as the ratio of energy consumed during a rapid indentation to the volume of indentation. The parameter which are taken into consideration are indentation depth, contact force, contact area, mean contact pressure.

Deterministic Contact Model of a Rough Surface Against a Flat-Layered Surface

2004 ◽  
Author(s):  
H. R. Pasaribu ◽  
D. J. Schipper
Keyword(s):  
Mechanical Properties ◽  
Rough Surface ◽  
Contact Area ◽  
Indentation Depth ◽  
Normal Load ◽  
Contact Model ◽  
Real Contact Area ◽  
Single Asperity ◽  
Real Contact ◽  
Effective Mechanical Properties

The effective mechanical properties of a layered surface vary as a function of indentation depth and the values of these properties range between the value of the layer itself and of the substrate. In this paper, a layered surface is modelled like a solid that has effective mechanical properties as a function of indentation depth by assuming that the layer is perfectly bounded to the substrate. The normal load as a function of indentation depth of sphere pressed against a flat layered surface is calculated using this model and is in agreement with the experimental results published by El-Sherbiney (1975), El-Shafei et al. (1983), Tang & Arnell (1999) and Michler & Blank (2001). A deterministic contact model of a rough surface against a flat layered surface is developed by representing a rough surface as an array of spherically shaped asperities with different radii and heights (not necessarily Gaussian distributed). Once the data of radius and height of every single asperity is obtained, one can calculate the number of asperities in contact, the real contact area and the load carried by the asperities as a function of the separation.

Mechanical Properties of the Human Elbow Bones Measured by Nanoindentation and Microindentation

2018 ◽  
Author(s):  
Dilpreet Singh ◽  
Pulak Mohan Pandey ◽  
Dinesh Kalyanasundaram
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Hierarchical Structure ◽  
Longitudinal Direction ◽  
Measurement Scales ◽  
Depth Of Penetration ◽  
Mechanical Environment ◽  
Physiological Loading ◽  
Bone Properties ◽  
Osteonal Bone

In this article, the nano and microhardness and the elastic modulus of the human elbow bones (humerus, ulna and radius) were studied. The nano properties were studied using load controlled technique with a load of 20 mN, while the micro properties were studied under 1 N load. A total of nine bone samples from three cadavers of ages between 45 and 55 years were tested. The measurements were carried out on both osteonal and interstitial bone in the longitudinal direction. The nanoindentation results indicated higher values for interstitial bone (hardness: 0.74 ± 0.09 GPa, elastic modulus: 19.05 ± 1.92 GPa) than for osteonal bone (hardness: 0.53 ± 0.05 GPa, elastic modulus: 16.66 ± 1.55 GPa). Consistent results were obtained at a depth of penetration between 1.1 μm to 1.5 μm in nanoindentation. In the case of microindentation, the microhardness and elastic modulus of interstitial bone was found to be 0.65 ± 0.07 GPa and 20.60 ± 2.27 GPa. Whereas for osteonal bone it was observed to be 0.60 ± 0.08 GPa and 14.56 ± 1.42 GPa respectively. The depth of penetration varies between the 8 μm to 11 μm for microindentation studies. In both measurement scales, a noticeable difference was observed between the osteonal and interstitial bone properties. As bone is a hierarchical structure, identifying the mechanical properties at the lamellar level helps in understanding the local mechanical environment of basic elements of the bones and predicting the behavior of the bone due to physiological loading.

Molecular dynamics study on the tensile properties of graphene/Cu nanocomposite

2017 ◽  
Vol 06 (03) ◽  
pp. 1750021 ◽  
Author(s):  
Jun Hua ◽  
Zhirong Duan ◽  
Chen Song ◽  
Qinlong Liu
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Comparative Analysis ◽  
Strain Rate ◽  
Ultimate Strength ◽  
Strain Rates ◽  
Single Crystal Copper ◽  
Single Slice

In this paper, the mechanical properties, including elastic properties, deformation mechanism, dislocation formation and crack propagation of graphene/Cu (G/Cu) nanocomposite under uniaxial tension are studied by molecular dynamics (MD) method and the strain rate dependence is also investigated. Firstly, through the comparative analysis of tensile results of single crystal copper (Cu), single slice graphene/Cu (SSG/Cu) nanocomposite and double slice graphene/Cu (DSG/Cu) nanocomposite, it is found that the G/Cu nanocomposites have larger initial equivalent elastic modulus and tensile ultimate strength comparing with Cu and the more content of graphene, the greater the tensile strength of composites. Afterwards, by analyzing the tensile results of SSG/Cu nanocomposite under different strain rates, we find that the tensile ultimate strength of SSG/Cu nanocomposite increases with the increasing of strain rate gradually, but the initial equivalent elastic modulus basically remains unchanged.

Influences of stress on the measurement of mechanical properties using nanoindentation: Part I. Experimental studies in an aluminum alloy

1996 ◽  
Vol 11 (3) ◽  
pp. 752-759 ◽  
Author(s):  
T. Y. Tsui ◽  
W. C. Oliver ◽  
G. M. Pharr
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Elastic Modulus ◽  
Contact Area ◽  
Experimental Studies ◽  
Analysis Procedure ◽  
Apparent Stress ◽  
Stress Dependence ◽  
Standard Methods ◽  
Hardness Tests

The influence of applied stress on the measurement of hardness and elastic modulus using nanoindentation methods has been experimentally investigated using special specimens of aluminum alloy 8009 to which controlled stresses could be applied by bending. When analyzed according to standard methods, the nanoindentation data reveal changes in hardness with stress similar to those observed in conventional hardness tests. However, the same analysis shows that the elastic modulus changes with stress by as much as 10%, thus suggesting that the analysis procedure is somehow deficient. Comparison of the real indentation contact areas measured optically to those determined from the nanoindentation data shows that the apparent stress dependence of the modulus results from an underestimation of the contact area by the nanoindentation analysis procedures.

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.

Mechanical Properties of Nanometre Volumes of Material: use of the Elastic Response of Small Area Indentations

1988 ◽  
Vol 130 ◽  
Author(s):  
J. B. Pethica ◽  
W. C. Oliver
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Contact Area ◽  
Small Area ◽  
Differential Method ◽  
Elastic Response ◽  
Plastic Hardness ◽  
Small Indentation ◽  
The Ideal

AbstractA new, differential method for determining the stiffness of a sub-micron indentation contact area is presented. This allows measurement of elastic modulus as well as plastic hardness, continuously during a single indentation, and without the need for discrete unloading cycles. Some of the new experiments that become possible with this technique, especially at the nanometre scale, are described. We show quantitatively that electropolished tungsten reproducibly exhibits the ideal theoretical lattice strength at small indentation loads.

A Load-Based Depth-Sensing Indentation Technique for Elastic-Plastic Material Mechanical Property Evaluation

2010 ◽  
Author(s):  
K. Lee ◽  
J. M. Tannenbaum ◽  
B. S.-J. Kang ◽  
M. A. Alvin
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Strain Hardening ◽  
Strain Curve ◽  
Strain Hardening Exponent ◽  
Depth Sensing ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Indentation Technique ◽  
Micro Indentation

A load-based depth-sensing micro-indentation technique has been developed for material mechanical properties evaluation including elastic modulus, yield stress, strain hardening exponent and stress-strain curve. Based on a Hertzian contact mechanics approach, this load-based depth-sensing micro-indentation technique does not require system compliance calibration or the use of high precision depth sensors. Furthermore a unique, material independent, indentation based load-depth algorithm has been developed accounting for both elastic and elastic-plastic deformation of the material beneath the indenter. This algorithm, found to be a function of material yield stress, strain hardening exponent and elastic modulus, is shown to be the basis for obtaining a stress-strain curve. Finite element analyses of multiple materials with various mechanical properties were employed to examine and develop the fundamental indention based relationships between these variables and the load/depth curve needed to extract the stress-strain diagram. In addition, experimental results obtained with this load-based micro-indentation technique were found to yield accurate material mechanical properties (elastic modulus, strain hardening, yield strength) at room and elevated temperatures (up to 1200°C).

scholarly journals Application of a Deterministic Contact Model to Analyze the Contact of a Rough Surface Against a Flat Layered Surface

2005 ◽  
Vol 127 (2) ◽  
pp. 451-455 ◽  
Author(s):  
H. R. Pasaribu ◽  
D. J. Schipper
Keyword(s):  
Mechanical Properties ◽  
Rough Surface ◽  
Contact Area ◽  
Indentation Depth ◽  
Deterministic Model ◽  
Total Load ◽  
Non Gaussian ◽  
Gaussian Surface ◽  
Total Contact Area ◽  
Effective Mechanical Properties

In this paper, a rough surface is modeled as an array of asperities represented by spheres with different radii and heights to be able to calculate the deformation (elastic, elastic-plastic, and plastic) at each asperity in contact. The total contact area and the total load carried are calculated by summarizing respectively the contact area and the load carried by each individual asperity (deterministic model). This model will diminish the assumption of an average asperity radius and enable one to calculate the contact of non-Gaussian surface more precisely. Further, in this paper, the deterministic model is used to analyze the contact behavior of a rough surface against a flat layered surface by modeling the flat layered surface as a solid that has effective mechanical properties as a function of indentation depth.

Properties of Hemp Fibres Reinforced PLA Composites

2019 ◽  
Vol 800 ◽  
pp. 205-209 ◽  
Author(s):  
Anete Smoca ◽  
Silvija Kukle ◽  
Zane Zelсa
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Composite Material ◽  
Elastic Modulus ◽  
Comparative Analysis ◽  
Composite Materials ◽  
Fixed Temperature ◽  
Hemp Fibers ◽  
Relative Extension ◽  
Hemp Fibres

In this study 3 samples of bio-composite materials with different proportion of hemp fibers in the PLA matrix were developed, their comparative analysis and certain mechanical properties were investigated. Bio-composite hemp and polylactide (PLA) fibers were evenly blended using carding technology. The obtained blanks were treated for thermosetting at a fixed temperature of 180°C and a pressure of 100 kN, as well as controlled heating, compression and cooling time were applied. The mechanical properties (tensile strength σt, elastic modulus Et, relative extension ɛt) of composite material were determined.

EFFECT OF MECHANICAL PROPERTIES OF THE SUBSTRATE TISSUES ON THE DETERMINATION OF ELASTIC MODULUS OF THE SCLERA USING INDENTATION TEST

2016 ◽  
Vol 16 (07) ◽  
pp. 1650085
Author(s):  
XIUQING QIAN ◽  
KUNYA ZHANG ◽  
ZHICHENG LIU
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
Elastic Modulus ◽  
Elastic Moduli ◽  
Indentation Depth ◽  
Vitreous Body ◽  
Indentation Test ◽  
Posterior Pole

The sclera is an important connective tissue that protects the sensitive layers within the eyeball. Identifying the mechanical properties of the sclera near the posterior pole is necessary to analyze the deformation of the sclera and stresses changing in the optic nerve head tissues. We propose a method to determine the mechanical properties of the sclera using dimensional analysis, finite element method and the indentation test. The elastic moduli of the sclera for different indentation depths and positions were identified. We found that the elastic moduli of the sclera varied with indentation depth. This was due to the effect of the mechanical properties of the substrate tissues inside the sclera. The elastic modulus of the choroid had the biggest effect on the determination of elastic modulus of the sclera, whereas that of the vitreous body could be ignored when the ratio of the indentation depth to the thickness of the sclera was less than 0.5. The effects of mechanical properties of the substrate tissues become more pronounced at greater indentation depths.

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