An experimental method to determine the contact radius changes during a spherical instrumented indentation

Collin, Jean-Marc; Mauvoisin, Gérard; Abdi, R. El

doi:10.1016/j.mechmat.2007.10.002

Cited by 26 publications

(30 citation statements)

References 12 publications

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“…Several dual indenter methods exist [2,13,[17][18][19][20] but with other dimensionless functions than Eqs. (7)- (9). Apart from adopting a second indenter, increasing the penetration depth decreases the likeliness that the force-depth curve is the same for the different materials.…”

Section: Uniqueness Of the Solutionmentioning

confidence: 98%

“…Two different indentation responses may occur; pile-up and sink-in as illustrated on Figure 4. Multiple authors [5][6][7]9] developed equations to predict pile-up and sink-in for certain material groups. The tendency towards pile-up increases with decreasing strain hardening exponent and ratio [10].…”

Section: Relationship Between Indentation Force-depth and Stress-stramentioning

confidence: 99%

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Instrumented indentation for determination of full range stress-strain curves

Smedt

Hertelé

Verstraete

et al. 2014

SCAD

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Abstract:One common method for the determination of full range stress-strain curves by instrumented indentation is presented and validated for an aluminium alloy. This method relates properties describing the indentation force-depth curve with those describing the uniaxial stress-strain curve as traditionally obtained from a tensile test. The first aim of this paper is to explain the basic concepts of instrumented indentation. Next, the analysis method is presented and validated. This study ends with discussing the uniqueness of the obtained solution. It is concluded that accurate determination of stress-strain behaviour can be realized, but for certain materials two indentations are needed.

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Section: Uniqueness Of the Solutionmentioning

confidence: 98%

Section: Relationship Between Indentation Force-depth and Stress-stramentioning

confidence: 99%

Instrumented indentation for determination of full range stress-strain curves

Smedt

Hertelé

Verstraete

et al. 2014

SCAD

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show abstract

“…Collin and his co-workers [6] proposed an empirical procedure to deduce both the indenter deformation and the contact radius using the indenter and sample elastic properties and several loading-unloading and reloading cycles. They introduced an equation [8] that omitted the deformation of sphere and resulted in the real amount of penetration.…”

Section: Location Of Figure1mentioning

confidence: 99%

“…This can be a result of using the simplified material properties in the numerical simulations that did not correspond to the real material behavior. Furthermore, equation (2) did not take into account the radial displacements of material under the indenter [6]. Hay and Wolff [7] then introduced a factor of γ and the contact stiffness equation became:…”

Section: Introductionmentioning

confidence: 99%

An Alternative Approach to Determine Material Characteristics Using Spherical Indentation and Neural Networks for Bulk Metals

Mahmoudi

Nourbakhsh

Amali

2012

Journal of Testing and Evaluation

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Material characteristics such as Young modulus, yield, and ultimate stresses are often considered as fundamental material parameters. Determination of material characteristics using the instrumented indentation test has gained interest among many researchers. The output of a spherical indentation test is usually the load-penetration (P-h) curve which is used to determine the Hollomon’s equation coefficients. Ideally, the elastic deformation of the sphere is to be excluded from the total displacement. However, the available techniques to omit the elastic deformation of the sphere are difficult-to-use and time consuming. In the present work, a noticeably simplified method is proposed to determine the load-displacement curve, preserving the required accuracy. The coefficients of Hollomon’s equation are then determined using the spherical indentation. The proposed method has also the ability to specify the unloading curve at each point of interest, even if the experimental data of the unloading procedure at that point is not available. Finally, by training a neural network and extracting the weights of its layers, an equation governing the network is presented explicitly. This expression makes the neural network easy to use. Furthermore, the proposed method is verified using the experimental results and method and experiment are shown to be in good agreement.

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“…In instrumented indentation test the load (L) and the penetration (P) of an indenter on the sample are measured. It has been shown that L-P curve can be converted to monotonic stress-strain curve of the material [23]. On the other hand, the stress-strain curve can be defined through an empirical equation known as material model.…”

Section: Introductionmentioning

confidence: 99%