On the sensitivity characteristics in the determination of the elastic and plastic properties of materials through multiple indentation

2007 ◽  
Vol 22 (4) ◽  
pp. 1043-1063 ◽  
Author(s):  
Hongzhi Lan ◽  
T.A. Venkatesh
Keyword(s):  
Spherical Indentation ◽  
Plastic Properties ◽  
Reverse Analysis ◽  
Properties Of Materials ◽  
Sharp Indentation ◽  
Comprehensive Study

A comprehensive study of the sensitivity characteristics associated with the determination of the elasto-plastic properties of a large number of materials using several combinations of dual, triple, and quadruple sharp indentation, and spherical indentation illustrates that: (i) The lowest sensitivity to the determination of plastic properties is observed for the indenter combination that corresponds either to the largest difference in the corresponding representative stresses or the largest difference in the indenter apex angles. (ii) The triple or quadruple sharp indenter combinations considered in the present study do not show a significant improvement in the sensitivity characteristics when compared to that of the dual sharp indentation. (iii) In the determination of plastic properties through spherical indentation where two representative stresses are invoked, the highest and the lowest sensitivity, respectively, are observed for the combinations in which the differences in the representative stresses are the lowest and the highest. The sensitivity is further reduced if a large number of representative stresses are considered for the reverse analysis.

scholarly journals Numerical verification for instrumented spherical indentation techniques in determining the plastic properties of materials

2009 ◽  
Vol 24 (12) ◽  
pp. 3653-3663 ◽  
Author(s):  
Taihua Zhang ◽  
Peng Jiang ◽  
Yihui Feng ◽  
Rong Yang
Keyword(s):  
Numerical Experiments ◽  
Spherical Indentation ◽  
Numerical Verification ◽  
Instrumented Indentation ◽  
Plastic Properties ◽  
Wide Range ◽  
Validity Range ◽  
Indentation Tests ◽  
Properties Of Materials ◽  
Indentation Methods

Instrumented indentation tests have been widely adopted for elastic modulus determination. Recently, a number of indentation-based methods for plastic properties characterization have been proposed, and rigorous verification is absolutely necessary for their wide application. In view of the advantages of spherical indentation compared with conical indentation in determining plastic properties, this study mainly concerns verification of spherical indentation methods. Five convenient and simple models were selected for this purpose, and numerical experiments for a wide range of materials are carried out to identify their accuracy and sensitivity characteristics. The verification results show that four of these five methods can give relatively accurate and stable results within a certain material domain, which is defined as their validity range and has been summarized for each method.

A Novel Method to Extract the Plastic Properties of Metal Materials from a Continuous Spherical Indentation Test

2017 ◽  
Vol 734 ◽  
pp. 206-211 ◽  
Author(s):  
Zhuang Jin ◽  
Jian Ping Zhao
Keyword(s):  
Strain Hardening ◽  
Indentation Test ◽  
New Method ◽  
Spherical Indentation ◽  
Strain Hardening Exponent ◽  
Computational Results ◽  
Plastic Properties ◽  
Novel Method ◽  
Properties Of Materials ◽  
Metal Materials

Cao and Lu had built a method to acquire the properties of materials. But they neglected the influence of strain hardening exponent n by introducing the representative strain which didan’t have any physical meaning. A new method from a continuous spherical indentation test was built, the influence of strain hardening exponent n were considered and the formulas of dimensionless functions defined in their work were improved in this present paper. Then the computational results from the new method and the actual results were compared and the error is about 8%.

ESTIMATION OF ANISOTROPIC PLASTIC PROPERTIES OF ENGINEERING STEELS FROM SPHERICAL IMPRESSIONS

2010 ◽  
Vol 02 (02) ◽  
pp. 355-379 ◽  
Author(s):  
KEISHI YONEDA ◽  
AKIO YONEZU ◽  
HIROYUKI HIRAKATA ◽  
KOHJI MINOSHIMA
Keyword(s):  
Yield Stress ◽  
Work Hardening ◽  
Spherical Indentation ◽  
Element Analysis ◽  
Plastic Properties ◽  
Indentation Force ◽  
Hardening Law ◽  
Anisotropic Plastic ◽  
Reverse Analysis ◽  
Force Displacement

This study proposes a method of reverse analysis to estimate the anisotropic plastic properties of engineering steels by spherical indentation. The method takes into consideration materials that obey the work-hardening law and show in-plane anisotropic yield stress. Finite element analysis was first carried out to compute the indentation behavior of such materials, showing that a permanent impression exhibited an anisotropic shape which was strongly dependent on the orthotropic axis. Based on the anisotropy of the impression geometry, we developed a simple approach to determine the yield stress, work-hardening exponent and yield stress ratio. The approach consists of several functions related to the parameters of two impression geometries, produced by dual spherical indentations with different indentation forces. Since the present method uses only two impression geometries and does not necessitate indentation force — displacement curves (indentation curves), it is a particularly useful technique to evaluate "indistinguishable materials" which are special sets of materials with distinct plastic properties, yet yield almost identical indentation curves.

An algorithm to determine the plastic properties of materials based on the loading data in single sharp indentation

2007 ◽  
Vol 1049 ◽  
Author(s):  
Akio Yonezu ◽  
Hiroyuki Hirakata ◽  
Kohji Minoshima
Keyword(s):  
Yield Stress ◽  
Unique Solution ◽  
Dimensional Analysis ◽  
Experimental Basis ◽  
Bulk Materials ◽  
Plastic Properties ◽  
Indentation Curve ◽  
Effective Yield ◽  
Properties Of Materials ◽  
Sharp Indentation

AbstractWe proposed a method to determine the plastic properties of bulk materials based on data of loading curvature in indentation curve with only one sharp indenter. This method uses the dimensional analysis to solve the representative stress and effective yield stress. Indentation unloading data is only used to select the unique solution from the calculated ones obtained from representative stress and effective yield stress. We applied the proposed method to four engineering metals on an experimental basis, to verify its effectiveness, as well as its superiority to the reported methods.

Contact Problems at Nano/Microscale and Depth Sensing Indentation Techniques

2010 ◽  
Vol 662 ◽  
pp. 53-76 ◽  
Author(s):  
Feodor M. Borodich
Keyword(s):  
Elastic Modulus ◽  
Direct Method ◽  
Contact Problems ◽  
Work Of Adhesion ◽  
Depth Sensing ◽  
Plastic Properties ◽  
Type Contact ◽  
Indentation Tests ◽  
Properties Of Materials

An overview of development of indentation techniques and connections between contact mechanics and methods of extracting mechanical characteristics from indentation data is given. Observed disagreements between the experimental observations and the models of indentation are discussed. It is shown that this disagreement is often caused by violation of hypotheses that are used in the formulation of the appropriate boundary-value contact problems and strictly speaking one cannot apply directly the solutions of Hertz type contact problems to indentation tests employing the sharp indenters. It is shown that commonly used experimental test involving sharp pyramidal and conical indenters may be applied to study plastic properties of materials while this approach is not very accurate for estimations of elastic modulus of the test solid. The recently proposed by Borodich and Galanov non-direct method that employs data of elastically loading of a spherical indenter is described. It is argued that the non-direct method can be used for determination of both the work of adhesion and elastic modulus of the tested material.

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