Identification of anisotropic plasticity properties of materials using spherical indentation imprint mapping

Residual stresses, existed in engineering structures, could significantly influence the mechanical properties of structures. Accurate and non-destructive evaluation of the non-equibiaxial residual stresses in these structures is of great value for predicting their mechanical performance. In this work, investigating the mechanical behaviors of instrumented spherical indentation on stressed samples revealed that non-equibiaxial residual stresses could shift the load-depth curve upwards or downwards and cause the residual indentation imprint to be an elliptical one. Through theoretical, experimental, and finite element (FE) analyses, two characteristic indentation parameters, i.e., the relative change in loading curvature and the asymmetry factor of the residual indentation imprint, were found to have optimal sensitivity to residual stresses at a depth of 0.01R (R is the radius of spherical indenter). With the aid of dimensional analysis and FE simulations, non-equibiaxial residual stresses were quantitatively correlated with these two characteristic indentation parameters. The spherical indentation method was then proposed to evaluate non-equibiaxial residual stress based on these two correlations. Applications were illustrated on metallic samples (AA 7075-T6 and AA 2014-T6) with various introduced stresses. Both the numerical and experimental verifications demonstrated that the proposed method could evaluate non-equibiaxial surface residual stresses with reasonable accuracy.

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

Journal of Materials Research ◽

10.1557/jmr.2009.0428 ◽

2009 ◽

Vol 24 (12) ◽

pp. 3653-3663 ◽

Cited By ~ 6

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.

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A Combined Numerical and Experimental Approach to Evaluate the Hardness of AA Aluminum 6063 T6 with A Ni-P Coating

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.827.209 ◽

2019 ◽

Vol 827 ◽

pp. 209-215

Author(s):

B. Juan S. León ◽

Alberto Pertuz ◽

M. Martínez

Keyword(s):

Experimental Data ◽

Experimental Approach ◽

Brinell Hardness ◽

Indentation Test ◽

Contact Radius ◽

Spherical Indentation ◽

The Finite Element Method ◽

Hard Materials ◽

A Value ◽

Properties Of Materials

The need to improve the surface properties of materials, has led to the development of parts coated with hard materials deposited on substrates. In this work, by using the finite element method the AA Aluminium 6063 T6 hardness with an error less of the 5 % of the Brinell hardness (HBN), in comparison with the experimental data supplied, was determined. For this, the modelling of a spherical indentation test was carried out, in which the indentation loads and the projected contact radius are obtained from several potential adjustments. Then, using the Lessage-Pertúz model the hardness of the Ni-P coating was determined, obtaining a value of 4.86 GPa.

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Determination of the proof strength and flow properties of materials from spherical indentation tests: An analytical approach based on the expanding cavity model

The Journal of Strain Analysis for Engineering Design ◽

10.1177/0309324718754960 ◽

2018 ◽

Vol 53 (4) ◽

pp. 225-241 ◽

Cited By ~ 10

Author(s):

Tairui Zhang ◽

Shang Wang ◽

Weiqiang Wang

Keyword(s):

Finite Element ◽

Calculation Method ◽

Force Balance ◽

Spherical Indentation ◽

Cavity Model ◽

Flow Properties ◽

Finite Element Calculations ◽

Indentation Tests ◽

Properties Of Materials ◽

Proof Strength

An analytical method based on the extended expanding cavity model was proposed in this study to determine the proof strength Rp0.2 and flow properties of materials that obey the Johnson–Cook constitutive model from spherical indentation tests. The introduction of the Johnson–Cook model made the proposed method suitable for the tensile property evaluation of materials not only at room temperature but also at elevated temperatures. The validity of the expanding cavity model was verified through comparisons of von Mises equivalent strain distributions obtained from finite element analyses with the corresponding results from theoretical analysis. From the parameter analysis, it was found that the indentation governing parameter ψempirical in the empirical method was actually determined by the tangential modulus Ep and the hardening exponent n and thus should not be considered as a constant. We also analyzed the unreliability of previous plastic zone radius rp calculation method at large indentation depths (with obvious pileup phenomenon) and put forward a new calculation method of rp based on the force balance. Finite element calculations of spherical indentation tests with tensile properties of Ti6Al4V and AISI 4340 were conducted in this study as substitutes for spherical indentation tests. The load–depth data and rp from finite element calculations were employed in the reverse analysis, the results of which showed that spherical indentation tests can provide the same reliable Rp0.2 as tensile tests and even the whole stress–strain curves. Furthermore, the influence of friction and the measuring system strain threshold in the measurement of rp, which may be inevitable in experiments, were also thoroughly discussed in this study, which also helped to verify the robustness of this study.

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.734.206 ◽

2017 ◽

Vol 734 ◽

pp. 206-211 ◽

Cited By ~ 3

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%.

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Probing out-of-plane anisotropic plasticity using spherical indentation: A numerical approach

Computational Materials Science ◽

10.1016/j.commatsci.2013.05.020 ◽

2013 ◽

Vol 79 ◽

pp. 336-344 ◽

Cited By ~ 3

Author(s):

Akio Yonezu ◽

Masanori Tanaka ◽

Ryota Kusano ◽

Xi Chen

Keyword(s):

Numerical Approach ◽

Spherical Indentation ◽

Anisotropic Plasticity ◽

Out Of Plane

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

Journal of Materials Research ◽

10.1557/jmr.2007.0123 ◽

2007 ◽

Vol 22 (4) ◽

pp. 1043-1063 ◽

Cited By ~ 18

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.

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