scholarly journals Evaluation of the effectiveness of representative methods for determining Young's modulus and hardness from instrumented indentation data

2006 ◽  
Vol 21 (1) ◽  
pp. 225-233 ◽  
Author(s):  
Dejun Ma ◽  
Taihua Zhang ◽  
Chung Wo Ong
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Maximum Error ◽  
Instrumented Indentation ◽  
Modulus Ratio ◽  
Material Parameters ◽  
Correction Scheme ◽  
Single Standard ◽  
Hardness Values ◽  
Hardening Coefficient

The effectiveness of Oliver & Pharr's (O&P's) method, Cheng & Cheng's (C&C’s) method, and a new method developed by our group for estimating Young's modulus and hardness based on instrumented indentation was evaluated for the case of yield stress to reduced Young's modulus ratio (σy/Er) ≥ 4.55 × 10−4 and hardening coefficient (n) ≤ 0.45. Dimensional theorem and finite element simulations were applied to produce reference results for this purpose. Both O&P's and C&C's methods overestimated the Young's modulus under some conditions, whereas the error can be controlled within ±16% if the formulation was modified with appropriate correction functions. Similar modification was not introduced to our method for determining Young's modulus, while the maximum error of results was around ±13%. The errors of hardness values obtained from all the three methods could be even larger and were irreducible with any correction scheme. It is therefore suggested that when hardness values of different materials are concerned, relative comparison of the data obtained from a single standard measurement technique would be more practically useful. It is noted that the ranges of error derived from the analysis could be different if different ranges of material parameters σy/Er and n are considered.

An improved energy method for determining Young’s modulus by instrumented indentation using a Berkovich tip

2008 ◽  
Vol 23 (8) ◽  
pp. 2106-2115 ◽  
Author(s):  
Dejun Ma ◽  
Chung Wo Ong ◽  
Taihua Zhang
Keyword(s):  
Aluminum Alloy ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Total Work ◽  
Instrumented Indentation ◽  
Modulus Ratio ◽  
6061 Aluminum Alloy ◽  
Functional Relationships ◽  
Two Parameters ◽  
Special Case

We previously proposed a method for estimating Young’s modulus from instrumented nanoindentation data based on a model assuming that the indenter had a spherical-capped Berkovich geometry to take account of the bluntness effect. The method is now further improved by releasing the constraint on the tip shape, allowing it to have a much broader arbitrariness to range from a conical-tipped shape to a flat-ended shape, whereas the spherical-capped shape is just a special case in between. This method requires two parameters to specify a tip geometry, namely, a volume bluntness ratio Vr and a height bluntness ratio hr. A set of functional relationships correlating nominal hardness/reduced elastic modulus ratio (Hn/Er) and elastic work/total work ratio (We/W) were established based on dimensional analysis and finite element simulations, with each relationship specified by a set of Vr and hr. Young’s modulus of an indented material can be estimated from these relationships. The method was shown to be valid when applied to S45C carbon steel and 6061 aluminum alloy.

scholarly journals A Quasi-Static Quantitative Ultrasound Elastography Algorithm Using Optical Flow

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3010
Author(s):  
Raphael Lamprecht ◽  
Florian Scheible ◽  
Marion Semmler ◽  
Alexander Sutor
Keyword(s):  
Optical Flow ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Image Data ◽  
Maximum Error ◽  
Ultrasound Elastography ◽  
Static Compression ◽  
Tissue Properties ◽  
A Performance

Ultrasound elastography is a constantly developing imaging technique which is capable of displaying the elastic properties of tissue. The measured characteristics could help to refine physiological tissue models, but also indicate pathological changes. Therefore, elastography data give valuable insights into tissue properties. This paper presents an algorithm that measures the spatially resolved Young’s modulus of inhomogeneous gelatin phantoms using a CINE sequence of a quasi-static compression and a load cell measuring the compressing force. An optical flow algorithm evaluates the resulting images, the stresses and strains are computed, and, conclusively, the Young’s modulus and the Poisson’s ratio are calculated. The whole algorithm and its results are evaluated by a performance descriptor, which determines the subsequent calculation and gives the user a trustability index of the modulus estimation. The algorithm shows a good match between the mechanically measured modulus and the elastography result—more precisely, the relative error of the Young’s modulus estimation with a maximum error 35%. Therefore, this study presents a new algorithm that is capable of measuring the elastic properties of gelatin specimens in a quantitative way using only the image data. Further, the computation is monitored and evaluated by a performance descriptor, which measures the trustability of the results.

Evaluation of Young’s modulus of construction materials by instrumented indentation using a ball indenter

2021 ◽  
Vol 87 (8) ◽  
pp. 64-68
Author(s):  
V. M. Matyunin ◽  
A. Yu. Marchenkov ◽  
N. Abusaif ◽  
M. V. Goryachkina ◽  
R. V. Rodyakina ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
High Surface ◽  
Construction Materials ◽  
Contact Problems ◽  
Indentation Load ◽  
Test Material ◽  
Elastic Displacement ◽  
Large Radius ◽  
Instrumented Indentation

Methods for evaluation of Young’s modulus (Em) of structural materials by instrumented indentation using ball indenter have been considered. All these techniques are based on the solution of elastic contact problems performed by H. Hertz. It has been shown that registration of the initial elastic region in the «load – displacement» indentation diagram provides the Em determination for metals and alloys. However, it is necessary to evaluate accurately the elastic compliance of a device, to use an indenter with a large radius R, and ensure a high surface quality of the test material in advance. Methods for Em determation, when indentation diagrams are recorded in the elastoplastic indentation region, should include the effect of plastic deformation on the elastic displacement calculated by H. Hertz expression. However, it appeared essential to determine the relation between the elastic αel and plastic h components of the total elastoplastic displacement α and the elastic displacement α0 estimated by H. Hertz expression for a definite indentation load. A close correlation between α0 and αel is revealed for steels, aluminum, magnesium, and titanium alloys when using indenters with a radius of R = 0.2 – 5 mm (diameter D = 0.4 – 10 mm) and maximum indentation load Fmax = 47 – 29430 N (4.8 – 3000 kgf). It is also shown that a gradual decrease in Em is observed with an increase in R(D) at the same degree of loading F/D2 for the same material. This fact was explained by the scale factor effect.

scholarly journals Dependence of ultrasonic contact impedance hardness on Young’s modulus of elasticity of creep-resistant steels

ACTA IMEKO ◽  
2017 ◽  
Vol 6 (1) ◽  
pp. 27 ◽  
Author(s):  
Michal Junek ◽  
Jiri Janovec ◽  
Petr Duchacek
Keyword(s):  
Young’S Modulus ◽  
Power Unit ◽  
Modulus Of Elasticity ◽  
Young's Modulus ◽  
Contact Impedance ◽  
Hardness Tester ◽  
Experimental Part ◽  
Young’S Modulus Of Elasticity ◽  
Creep Resistant Steels ◽  
Hardness Values

<p class="Abstract"><span lang="EN-US">The paper deals with the hardness measurements by mobile UCI hardness testers as a means of determining the residual operation life of power unit components. It aims to answer questions regarding the level of dependence of UCI hardness on Young's modulus of creep-resistant steels and determining the conditions of a UCI hardness tester calibration. The experimental part describes comparative measurements of hardness values obtained using stationary hardness testers and UCI hardness testers.</span></p>

402 Hardness/Young's modulus ratio and tribology characteristics of hard thin film

2015 ◽  
Vol 2015.90 (0) ◽  
pp. 104-107
Author(s):  
Toshiyuki Saito ◽  
Miwa Hokii ◽  
Masahiro Suzuki
Keyword(s):  
Thin Film ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Modulus Ratio

Mechanics-based algorithms to determine the current state of a bridge using quasi-static loading and strain measurement

2018 ◽  
Vol 18 (5-6) ◽  
pp. 1874-1888 ◽  
Author(s):  
Pandi Pitchai ◽  
U Saravanan ◽  
Rupen Goswami
Keyword(s):  
Boundary Conditions ◽  
Young’S Modulus ◽  
Material Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
Young's Modulus ◽  
Moving Load ◽  
Material Parameters ◽  
Current State ◽  
Slow Moving

Knowing the current state of a bridge is of interest for a variety of reasons. Some parameters that determine the current state of a bridge are the material properties and boundary conditions. Using strain measurements obtained from a slow-moving vehicle on a bridge, the boundary condition and material properties are determined through a mechanistic-based approach. Observing that the sign of the curvature would change at locations near the support when a load passes over a bridge with end rotational restraints, a methodology for determining the boundary conditions is proposed and validated. The linear elastic properties of the material that the bridge is made up of is determined from the strain measured at locations where the stress is independent of the material property. In this procedure, the structure is analyzed assuming some material properties and the stress at the measured point is determined. Then, the material parameters in the isotropic Hooke’s law are determined so that the stress estimated from the experimentally determined strains agrees with that obtained from the analysis with arbitrarily assumed material parameters. A prestressed high-performance concrete pi-shaped girder tested under a three-axle slow-moving load with strains measured at different locations is used to bring out the efficacy and appropriateness of the proposed methodologies. The mean value of Young’s modulus of the prestressed concrete bridge agrees well with the experimentally determined Young’s modulus.

Identification of viscoplastic material parameters from spherical indentation data: Part II. Experimental validation of the method

2006 ◽  
Vol 21 (3) ◽  
pp. 677-684 ◽  
Author(s):  
D. Klötzer ◽  
Ch. Ullner ◽  
E. Tyulyukovskiy ◽  
N. Huber
Keyword(s):  
Yield Stress ◽  
Young’S Modulus ◽  
Experimental Validation ◽  
Young's Modulus ◽  
Surface Preparation ◽  
Small Variation ◽  
Application Rate ◽  
Spherical Indentation ◽  
Viscoplastic Material ◽  
Material Parameters

A neural network-based analysis method for the identification of a viscoplasticity model from spherical indentation data, developed in the first part of this work [J. Mater. Res.21, 664 (2006)], was applied for different metallic materials. Besides the comparison of typical parameters like Young’s modulus and yield stress with values from tensile experiments, the uncertainties in the identified material parameters representing modulus, hardening behavior, and viscosity were investigated in relation to different sources. Variations in the indentation position, tip radius, force application rate, and surface preparation were considered. The extensive experimental validation showed that the applied neural networks are very robust and show small variation coefficients, especially regarding the important parameters of Young’s modulus and yield stress. On the other hand, important requirements were quantified, which included a very good spherical indenter geometry and good surface preparation to obtain reliable results.

Young’s Modulus of Alumina Particles Reinforced Metal-Matrix Composite

2016 ◽  
Vol 368 ◽  
pp. 174-177
Author(s):  
Petr Haušild ◽  
Ondřej Kovářík ◽  
Kristýna Havlíková ◽  
Martina Thomasová
Keyword(s):  
Young’S Modulus ◽  
Matrix Composite ◽  
Young's Modulus ◽  
Instrumented Indentation ◽  
Internal Damage ◽  
Three Point Bending ◽  
Particle Cracking ◽  
Alumina Particles ◽  
Pulse Echo ◽  
Al Matrix Composite

Young’s modulus of alumina particles reinforced pure Al-matrix composite is characterized by different methods: the pulse-echo ultrasound method, static three point bending, resonant bending and continuous multicycle measurement by instrumented indentation. Dependency of apparent Young’s modulus on loading amplitude was observed and attributed to the local mechanical properties of both phases, especially to the development of internal damage (local plasticity and particle cracking).

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