scholarly journals Effective indenter radius and frame compliance in instrumented indentation testing using a spherical indenter

2009 ◽  
Vol 24 (9) ◽  
pp. 2965-2973 ◽  
Author(s):  
Seung-Kyun Kang ◽  
Ju-Young Kim ◽  
Ingeun Kang ◽  
Dongil Kwon
Keyword(s):  
Elastic Modulus ◽  
Spherical Indenter ◽  
Indentation Testing ◽  
Instrumented Indentation ◽  
Stress Strain ◽  
Contact Depth ◽  
Novel Method ◽  
Small Indentation ◽  
Indenter Geometry

We introduce a novel method to correct for imperfect indenter geometry and frame compliance in instrumented indentation testing with a spherical indenter. Effective radii were measured directly from residual indentation marks at various contact depths (ratio of contact depth to indenter radius between 0.1 and 0.9) and were determined as a function of contact depth. Frame compliance was found to depend on contact depth especially at small indentation depths, which is successfully explained using the concept of an extended frame boundary. Improved representative stress-strain values as well as hardness and elastic modulus were obtained over the entire contact depth.

A Scaling Approach to Modeling Indentation Measurements

2000 ◽  
Vol 649 ◽  
Author(s):  
Yang-Tse Cheng ◽  
Zhiyong Li ◽  
Che-Min Cheng
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Dimensional Analysis ◽  
Instrumented Indentation ◽  
Elastic Plastic ◽  
Contact Depth ◽  
Finite Element Calculations ◽  
Conical Indentation ◽  
Interpretation Of Results

ABSTRACTUsing dimensional analysis and finite element calculations, the relationships between hardness, elastic modulus, final contact depth, and the work of indentation are extended to conical indentation in elastic-plastic solids with various cone angles. These relationships provide new insights into indentation measurements. They may also be useful to the interpretation of results obtained from instrumented indentation experiments.

scholarly journals Creation of Ionically Crosslinked Tri-Layered Chitosan Membranes to Simulate Different Human Skin Properties

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1807
Author(s):  
Rocío Guerle-Cavero ◽  
Blanca Lleal-Fontàs ◽  
Albert Balfagón-Costa
Keyword(s):  
Elastic Modulus ◽  
Human Skin ◽  
Sodium Tripolyphosphate ◽  
Snow Crab ◽  
Suitable Material ◽  
Cosmetic Industry ◽  
Novel Method ◽  
Current Article ◽  
Chitosan Membranes

In 2023, new legislation will ban the use of animals in the cosmetic industry worldwide. This fact, together with ethical considerations concerning the use of animals or humans in scientific research, highlights the need to propose new alternatives for replacing their use. The aim of this study is to create a tri-layered chitosan membrane ionically crosslinked with sodium tripolyphosphate (TPP) in order to simulate the number of layers in human skin. The current article highlights the creation of a membrane where pores were induced by a novel method. Swelling index, pore creation, and mechanical property measurements revealed that the swelling index of chitosan membranes decreased and, their pore formation and elasticity increased with an increase in the Deacetylation Grade (DDA). Additionally, the results demonstrate that chitosan’s origin can influence the elastic modulus value and reproducibility, with higher values being obtained with seashell than snow crab or shrimp shells. Furthermore, the data show that the addition of each layer, until reaching three layers, increases the elastic modulus. Moreover, if layers are crosslinked, the elastic modulus increases to a much greater extent. The characterization of three kinds of chitosan membranes was performed to find the most suitable material for studying different human skin properties.

On Determining Elastic Modulus from Instrumented Indentation

2013 ◽  
Vol 668 ◽  
pp. 616-620
Author(s):  
Shuai Huang ◽  
Huang Yuan
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Plastic Material ◽  
Instrumented Indentation ◽  
Computational Simulations ◽  
Elastic Plastic ◽  
Modified Method ◽  
Plastic Materials ◽  
Elastic Plastic Material ◽  
Elastic Plastic Materials

Computational simulations of indentations in elastic-plastic materials showed overestimate in determining elastic modulus using the Oliver & Pharr’s method. Deviations significantly increase with decreasing material hardening. Based on extensive finite element computations the correlation between elastic-plastic material property and indentation has been carried out. A modified method was introduced for estimating elastic modulus from dimensional analysis associated with indentation data. Experimental verifications confirm that the new method produces more accurate prediction of elastic modulus than the Oliver & Pharr’s method.

scholarly journals Effect of growth conditions on the mechanical properties of lanthanum-gallium tantalate crystals

2020 ◽  
Vol 6 (2) ◽  
pp. 65-70
Author(s):  
Mark V. Weintraub ◽  
Nina S. Kozlova ◽  
Evgeniya V. Zabelina ◽  
Mikhail I. Petrzhik
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Elastic Recovery ◽  
Growth Conditions ◽  
Piezoelectric Response ◽  
Instrumented Indentation ◽  
Recovery Coefficient ◽  
Hardness Tester ◽  
Growth Atmosphere ◽  
Oxygen Addition

The effect of growth conditions, anisotropy and polarity of specimens on the mechanical properties of lanthanum-gallium tantalate La3Ta0.5Ga5.5O14 single crystals grown in different atmospheres (argon (Ar), argon with oxygen addition (Ar+(<2%)O2 and Ar+(2%)O2) and air) was studied. The test specimens for the measurements were cut perpendicularly to a 3rd order axis (Z cuts) and in polar directions perpendicular to a 2nd order axis (Y cuts). The polarity of the Y cut specimens was tested by piezoelectric response. The brittleness was evaluated by microindentation at 3, 5, 10 and 25 g loads. The brittleness proved to show itself at a 5 g and the higher loads regardless of growth atmosphere. Therefore microhardness tests were done at loads of within 3 g. The microhardness HV of the specimens was measured with an DM 8B Affri microhardness tester by Vickers methods. The hardness H, elastic modulus E and elastic recovery coefficient R were measured with a Berkovich pyramid on a CSM Nano-Hardness Tester using the instrumented indentation (nanoindentation) method. Growth atmosphere was shown to affect the mechanical properties of lanthanum-gallium tantalate crystals: crystals grown in an oxygen-free argon atmosphere had the lowest microhardness, hardness, elastic modulus and elastic recovery coefficient. The lowest microhardness was detected in Z cut specimens regardless of growth atmosphere. The mechanical properties of polar Y cuts proved to be anisotropic: the microhardness, hardness, elastic modulus and elastic recovery coefficient of these cuts were lower for positive cuts than for negative ones regardless of growth atmosphere. Y and Z cut langatate specimens grown in argon with less than two percent oxygen exhibited strong elastic modulus and elastic recovery coefficient anisotropy.

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