S0302-4-5 Spherical Indentation Testing to Evaluate Thickness and Young's Modulus of Soft Materials

2009 ◽  
Vol 2009.1 (0) ◽  
pp. 171-172
Author(s):  
Mitsuhiro TANI ◽  
Atsushi SAKUMA
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Soft Materials ◽  
Spherical Indentation ◽  
Indentation Testing

scholarly journals Evaluation of Thickness and Young's Modulus of Soft Materials by using Spherical Indentation Testing

2009 ◽  
Vol 75 (755) ◽  
pp. 901-908 ◽  
Author(s):  
Mitsuhiro TANI ◽  
Atsushi SAKUMA ◽  
Masamitsu SHINOMIYA
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Soft Materials ◽  
Spherical Indentation ◽  
Indentation Testing

scholarly journals Multi-material direct ink writing of photocurable elastomeric foams

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Osman Dogan Yirmibesoglu ◽  
Leif Erik Simonsen ◽  
Robert Manson ◽  
Joseph Davidson ◽  
Katherine Healy ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Transient Behavior ◽  
Soft Materials ◽  
Ammonium Bicarbonate ◽  
Structure Property ◽  
Direct Ink Writing ◽  
Material Chemistry ◽  
New Applications ◽  
Double Networks

AbstractDevelopments in additive manufacturing have enabled the fabrication of soft machines that can safely interface with humans, creating new applications in soft robotics, wearable technologies, and haptics. However, designing custom inks for the 3D printing of soft materials with Young’s modulus less than 100 kPa remains a challenge due to highly coupled structure-property-process relationship in polymers. Here, we show a three-stage material chemistry process based on interpenetrating silicone double networks and ammonium bicarbonate particles that decouples the transient behavior during processing from the final properties of the material. Evaporation of ammonium bicarbonate particles at the final stage creates gaseous voids to produce foams with a low effective Young’s modulus in the 25 kPa −90 kPa range. Our photoirradiation-assisted direct ink writing system demonstrates the ability to maintain high resolution while enabling controlled loading of ammonium bicarbonate particles. The resultant multi-material possesses programmed porosity and related properties such as density, stiffness, Shore hardness, and ultimate strength in a monolithic object. Our multi-hardness synthetic hand and self-righting buoyant structure highlight these capabilities.

scholarly journals Identification of Young’s Modulus from Indentation Testing and Inverse Analysis

2010 ◽  
Vol 4 (6) ◽  
pp. 781-795 ◽  
Author(s):  
Joris PROU ◽  
Kikuo KISHIMOTO ◽  
Andrei CONSTANTINESCU
Keyword(s):  
Young’S Modulus ◽  
Inverse Analysis ◽  
Young's Modulus ◽  
Indentation Testing

Robust Strategies for Automated AFM Force Curve Analysis—II: Adhesion-Influenced Indentation of Soft, Elastic Materials

2007 ◽  
Vol 129 (6) ◽  
pp. 904-912 ◽  
Author(s):  
David C. Lin ◽  
Emilios K. Dimitriadis ◽  
Ferenc Horkay
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Full Range ◽  
Soft Materials ◽  
Adhesive Contact ◽  
Colloid Interface ◽  
Inhomogeneous Materials ◽  
Dugdale Model ◽  
Normal Contact ◽  
Adhesive Interactions

In the first of this two-part discourse on the extraction of elastic properties from atomic force microscopy (AFM) data, a scheme for automating the analysis of force-distance curves was introduced and experimentally validated for the Hertzian (i.e., linearly elastic and noninteractive probe-sample pairs) indentation of soft, inhomogeneous materials. In the presence of probe-sample adhesive interactions, which are common especially during retraction of the rigid tip from soft materials, the Hertzian models are no longer adequate. A number of theories (e.g., Johnson–Kendall–Roberts and Derjaguin–Muller–Toporov), covering the full range of sample compliance relative to adhesive force and tip radius, are available for analysis of such data. We incorporated Pietrement and Troyon’s approximation (2000, “General Equations Describing Elastic Indentation Depth and Normal Contact Stiffness Versus Load,” J. Colloid Interface Sci., 226(1), pp. 166–171) of the Maugis–Dugdale model into the automated procedure. The scheme developed for the processing of Hertzian data was extended to allow for adhesive contact by applying the Pietrement–Troyon equation. Retraction force-displacement data from the indentation of polyvinyl alcohol gels were processed using the customized software. Many of the retraction curves exhibited strong adhesive interactions that were absent in extension. We compared the values of Young’s modulus extracted from the retraction data to the values obtained from the extension data and from macroscopic uniaxial compression tests. Application of adhesive contact models and the automated scheme to the retraction curves yielded average values of Young’s modulus close to those obtained with Hertzian models for the extension curves. The Pietrement–Troyon equation provided a good fit to the data as indicated by small values of the mean-square error. The Maugis–Dugdale theory is capable of accurately modeling adhesive contact between a rigid spherical indenter and a soft, elastic sample. Pietrement and Troyon’s empirical equation greatly simplifies the theory and renders it compatible with the general automation strategies that we developed for Hertzian analysis. Our comprehensive algorithm for automated extraction of Young’s moduli from AFM indentation data has been expanded to recognize the presence of either adhesive or Hertzian behavior and apply the appropriate contact model.

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.

Identification of viscoplastic material parameters from spherical indentation data: Part II. Experimental validation of the method

2006 ◽  
Vol 21 (3) ◽  
pp. 677-684 ◽  
Author(s):  
D. Klötzer ◽  
Ch. Ullner ◽  
E. Tyulyukovskiy ◽  
N. Huber
Keyword(s):  
Yield Stress ◽  
Young’S Modulus ◽  
Experimental Validation ◽  
Young's Modulus ◽  
Surface Preparation ◽  
Small Variation ◽  
Application Rate ◽  
Spherical Indentation ◽  
Viscoplastic Material ◽  
Material Parameters

A neural network-based analysis method for the identification of a viscoplasticity model from spherical indentation data, developed in the first part of this work [J. Mater. Res.21, 664 (2006)], was applied for different metallic materials. Besides the comparison of typical parameters like Young’s modulus and yield stress with values from tensile experiments, the uncertainties in the identified material parameters representing modulus, hardening behavior, and viscosity were investigated in relation to different sources. Variations in the indentation position, tip radius, force application rate, and surface preparation were considered. The extensive experimental validation showed that the applied neural networks are very robust and show small variation coefficients, especially regarding the important parameters of Young’s modulus and yield stress. On the other hand, important requirements were quantified, which included a very good spherical indenter geometry and good surface preparation to obtain reliable results.

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