Estimating material elasticity by spherical indentation load-relaxation tests on viscoelastic samples of finite thickness

2011 ◽  
Vol 58 (7) ◽  
pp. 1418-1429 ◽  
Author(s):  
Bo Qiang ◽  
J. Greenleaf ◽  
M. Oyen ◽  
Xiaoming Zhang
Keyword(s):  
Finite Thickness ◽  
Indentation Load ◽  
Spherical Indentation ◽  
Load Relaxation

Spherical indentation load-relaxation of soft biological tissues

2006 ◽  
Vol 21 (8) ◽  
pp. 2003-2010 ◽  
Author(s):  
Jason M. Mattice ◽  
Anthony G. Lau ◽  
Michelle L. Oyen ◽  
Richard W. Kent
Keyword(s):  
Costal Cartilage ◽  
Kidney Tissue ◽  
Biological Tissues ◽  
Indentation Load ◽  
Spherical Indentation ◽  
Load Relaxation ◽  
Soft Biological Tissues ◽  
Long Time ◽  
Constant Displacement ◽  
Soft Biological Materials

Elastic-viscoelastic correspondence was used to generate displacement–time solutions for spherical indentation testing of soft biological materials with time-dependent mechanical behavior. Boltzmann hereditary integral operators were used to determine solutions for indentation load-relaxation following a constant displacement rate ramp. A “ramp correction factor” approach was used for routine analysis of experimental load-relaxation data. Experimental load-relaxation tests were performed on rubber, as well as kidney tissue and costal cartilage, two hydrated soft biological tissues with vastly different mechanical responses. The experimental data were fit to the spherical indentation ramp-relaxation solutions to obtain values of short- and long-time shear modulus and of material time constants. The method is used to demonstrate linearly viscoelastic responses in rubber, level-independent indentation results for costal cartilage, and age-independent indentation results for kidney parenchymal tissue.

Finite Thickness Influence on Spherical and Conical Indentation on Viscoelastic Thin Polymer Film

2005 ◽  
Vol 127 (1) ◽  
pp. 33-37 ◽  
Author(s):  
V. Gonda ◽  
J. den Toonder ◽  
J. Beijer ◽  
G. Q. Zhang ◽  
L. J. Ernst
Keyword(s):  
Polymer Film ◽  
Material Properties ◽  
Finite Thickness ◽  
Thin Polymer Film ◽  
Spherical Indentation ◽  
Infinite Plane ◽  
Precise Knowledge ◽  
Thin Polymer ◽  
Measurement Results ◽  
Conical Indentation

The thermo-mechanical integration of polymer films requires a precise knowledge of material properties. Nanoindentation is a widely used testing method for the determination of material properties of thin films such as Young’s modulus and the hardness. An important assumption in the analysis of the indentation is that the indented medium is a semi-infinite plane or half space, i.e., it has an “infinite thickness.” In nanoindentation the analyzed material is often a thin film that is deposited on a substrate. If the modulus ratio is small, (soft film on hard substrate) and the penetration depth is small too, then the Hertzian assumption does not hold. We investigate this situation with spherical and conical indentation. Measurement results are shown using spherical indentation on a visco-elastic thin polymer film and a full visco-elastic characterization is presented.

Indentation load relaxation experiments with indentation depth in the submicron range

1990 ◽  
Vol 5 (10) ◽  
pp. 2100-2106 ◽  
Author(s):  
W. R. LaFontaine ◽  
B. Yost ◽  
R. D. Black ◽  
C-Y. Li
Keyword(s):  
Indentation Depth ◽  
Metal Films ◽  
Indentation Load ◽  
Hard Substrate ◽  
Flow Properties ◽  
Load Relaxation ◽  
Relaxation Data ◽  
Flow Curves ◽  
Relaxation Experiments

Indentation load relaxation (ILR) experiments with indentation depths in the submicron range are described. Under appropriate conditions, the ILR data are found to yield flow curves of the same shape as those based on conventional load relaxation data. Variations in flow properties as a function of depth in submicron metal films deposited on a hard substrate are detected by the experiments described.

Determination of the Elastic-Plastic Properties of 15Kh2MFA Steel with Austenitic Cladding

2013 ◽  
Vol 586 ◽  
pp. 43-46 ◽  
Author(s):  
Aleš Materna ◽  
Jiri Nohava ◽  
Petr Haušild ◽  
Vladislav Oliva
Keyword(s):  
Tensile Test ◽  
Indentation Test ◽  
Strain Curve ◽  
Indentation Load ◽  
Spherical Indentation ◽  
Compression Tests ◽  
Material Interface ◽  
Plastic Properties ◽  
Longitudinal Orientation ◽  
Sufficient Distance

The spherical indentation response of pressure vessel reactor steel with austenitic cladding is investigated both experimentally and numerically. The instrumented indentation test was performed for both materials at a sufficient distance from the bi-material interface, thus the results can be compared with the bulk data obtained from the standard tensile and compression tests. The stress – plastic strain curve for austenitic cladding estimated by a simplified inverse analysis of the indentation load – penetration curve is shifted to a harder response compared with that determined from the tensile test. One of the possible reasons, anisotropy of the cladding metal, was experimentally observed during the compression tests performed in the longitudinal orientation of the tensile test specimens and in the transverse orientation identical with the direction of the material indentation.

Residual stress model for CaF2

2007 ◽  
Vol 22 (10) ◽  
pp. 2796-2808
Author(s):  
Q. Zhang ◽  
J.C. Lambropoulos
Keyword(s):  
Removal Rate ◽  
Indentation Load ◽  
Contact Radius ◽  
Spherical Indentation ◽  
Stress Distributions ◽  
Element Analysis ◽  
Crystalline Anisotropy ◽  
Crystallographic Planes ◽  
Two Stages

Nanoindentation tests and finite element analysis that considers elastic-mesoplastic deformation for single crystals were used to investigate the mechanical properties of CaF2 under spherical indentation. The goal was to gain a better understanding of microfractures and crystalline anisotropy and their effect on the surface quality of CaF2 during manufacturing. In this analysis, indentations of the three main crystallographic planes (100), (110), and (111) were studied and compared to examine the effects of crystalline anisotropy on the load–displacement curves, surface profiles, contact radius, spherical hardness, stress distributions, and cleavage at two stages, namely at the maximum indentation load and after the load had been removed. Our model results were compared with experimental observation of surface microroughness, subsurface damage, and material removal rate in grinding of CaF2.

Indentation Load Relaxation Studies of Thin Film-Substrate Systems

1986 ◽  
Vol 72 ◽  
Author(s):  
D. Stone ◽  
W. Lafontaine ◽  
S. Ruoff ◽  
S.-P. Hannula ◽  
B. Yost ◽  
...  
Keyword(s):  
Thin Film ◽  
Aluminum Film ◽  
Indentation Load ◽  
Load Relaxation ◽  
Tin Film ◽  
Relaxation Studies ◽  
Film Substrate

AbstractResults from indentation load relaxation (ILR) tests on thin film-substrate systems are reported. In the case of a 1 pum aluminum film on silicon, the data can be interpreted as reflecting both the properties of the film and the interface between film and substrate. Data from a 37μm TiN film on 304 SS are believed to reflect the combined behavior of the film and substrate.

Softness Measurement Technics of Human Skin by Indentation Devices Imitating Palpation

2013 ◽  
Author(s):  
Atsushi Sakuma
Keyword(s):  
Young’S Modulus ◽  
Human Skin ◽  
Soft Tissues ◽  
Young's Modulus ◽  
Finite Thickness ◽  
The Body ◽  
Ultraviolet Rays ◽  
Spherical Indentation ◽  
Measurement Technology ◽  
Human Face

The characteristics of human skin are easily changed by the states of the body because it is very sensitive to environmental transformation. And the development of the condition measurement technology of human skin is very important for improvement in QOL because it reflects body condition. Then, various devices for the condition measurement of human skin had been developed but there was no technique which can evaluate the skin by objective parameter easily. In this paper, spherical indentation testing is studied to evaluate the dimension and rigidity of thin soft-tissues like human skin. Here, the Hertz contact theory is functionally expanded to evaluate indentations for the thin tissues. In the expansions, the technique used for evaluating the thickness of finite specimens is first explained by analyzing the experimental results of indentations. Then, the Young’s modulus of the tissue with finite thickness is theoretically derived by defining an equivalent indentation strain for the analysis of the indentation process. The expansions are examined to evaluate its reliability by applying them to measure Young’s modulus of some thin materials. Furthermore, this technology is applied to the elasticity investigation of the human skin. Especially, the measurement results of elasticity characteristics of the skin of human face are shown as the first report. The influences of sex and ultraviolet rays and so on are discussed to reveal the mechanics of human skin in this report. Moreover, it is discussed about the validity of the device which measures the elasticity of the skin of human face.

Meyer Law Application for Solving Problems of Surface Plastic Deformation by Spherical Indentation

2015 ◽  
Vol 788 ◽  
pp. 199-204 ◽  
Author(s):  
Peter Ogar ◽  
Denis Gorokhov
Keyword(s):  
Plastic Material ◽  
Surface Plastic Deformation ◽  
Indentation Load ◽  
Test Material ◽  
Spherical Indentation ◽  
Strain Hardening Exponent ◽  
Surface Plastic ◽  
Scope Of Application ◽  
Elastic Plastic Material ◽  
Comparison Of The Results

A method for determining contact characteristics occurring in spherical indentation depending on the properties of an elastic-plastic material governed by the hardening Hollomon power law is proposed. In this case the empirical Meyer law relating a spherical indentation load with an indentation diameter d is used. Basically, the Meyer law is not related to the mechanical characteristics of the test material. The study used the relations between the strain hardening exponent n and the Meyer law constant obtained by S.I. Bulychev. The effects of «sink-in / pile-up» are considered. It is shown that there is no need to define Meyer law constants. The scope of application of the proposed equations is defined. A comparison of the results obtained with the published results based on the finite element (FE) analysis is given.

Indentation Load Relaxation Experiments on Al-Si Metallizations

1990 ◽  
Vol 188 ◽  
Author(s):  
W. R. LaFontaine ◽  
B. Yost ◽  
R. D. Black ◽  
Che-Yu Li
Keyword(s):  
Flow Behavior ◽  
Indentation Load ◽  
Load Relaxation ◽  
Depth Of Penetration ◽  
Flow Curves ◽  
Bulk Specimen ◽  
Load Relaxation Test ◽  
Relaxation Experiments ◽  
Film Substrate ◽  
Penetration Depths

ABSTRACTIndentation load relaxation (ILR) experiments with indentation depths in the submicron range are described. The observed flow behavior of a 1μm thick A1-2%Si film deposited on a silicon substrate depended on the depth of penetration. For shallow penetration depths, the shape of the flow curves obtained from this sample are similar to those obtained from a conventional load relaxation test of a bulk specimen. For penetration depths close to the film/substrate interface, the influence of the substrate on the film's deformation behavior was observed.

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