In this paper, the authors present a new methodology to study the viscoelastic behaviour of the human finger. The methodology is based on experimental research consisting of a finger's indentation with a small steel cylindrical object for various indentation speeds. The tests were realized on a CETR UMT-2 Tribometer for indentation speed between 0.02 mm/s and 4 mm/s with a normal load of up to ...

PURPOSE To determine how mechanical interaction among iris, cornea, limbus, sclera, and IOP contribute to angle opening during indentation of the cornea or sclera. METHODS A finite-element model of the globe was developed. The model consisted of three elastic isotropic segments--iris, cornea, and sclera--and a two-component anisotropic segment representing the limbus. The model was tested aga...

Introduction Most in vivo indentation techniques are limited by the lack of adequate indentation on the plantar tissue. Without sufficient indentation into the soft tissue, only very little and less representative information can be obtained. The purpose of this study is hence to assess the effect of deformation depth on plantar tissue behavior and to establish a set rule of optimum indentation...

A number of magnetopause models have been developed in the course of last three decades. We have chosen seven of them and tested them using a fresh set of magnetopause crossings observed by Interball-1, Magion-4, and Geotail satellites. The crossings cover the magnetopause from the subsolar region up to near-Earth tail (XGSE ∼ −20 RE) and all geomagnetic latitudes. Our study reveals that (1) th...

The interlaminar interface of a crossply carbon fiber epoxy-matrix composite was found to be an impact sensor, with sensitivity to impact from 0.8 mJ to 5 J (though no indentation was observed) and to multiple (up to 35) impacts at the same energy. However, the sensing of a small impact after a large one was not effective if the small impact was much lower in energy than the large one. The high...

In this paper, static indentation and low velocity impact responses of a fully backed composite sandwich plate subjected to a rigid flat-ended cylindrical indenter/impactor are analytically investigated. The analysis is nonlinear due to nonlinear strain-displacement relation. In contrast to the existed analytical models for the indentation of composite sandwich plates, the stacking sequence of ...

We employ the Eshelby–Stroh formalism to study generalized plane strain infinitesimal deformations caused due to the indentation by a rigid circular cylinder of an elastic laminated plate with a throughthe-width rectangular void between two adjoining layers. Assuming that the void does not close during the indentation process, we find the indentation modulus (i.e., the slope of the indentation ...

The aim of this paper is to show that damage mechanisms can account for the response of lamellar bone to nanoindentation tests, with particular regards to the decrease of indentation stiffness with increasing penetration depth and to the loss of contact stiffness during the unloading phase of the test. For this purpose, indentation experiments on bovine cortical bone samples along axial and tra...

The application of the concept of the representative strain is often used in the stress-strain curve determination from indentation test because it can significantly simplify the analysis of the indentation response. A new methodology for determining the representative strain for Vickers indentation is presented in this article. Following a procedure based on finite element simulations of inden...

ÐThe response of lead zirconate titanate and barium titanate piezoelectric ceramics to spherical microindentation was investigated. Force vs penetration depth curves obtained from instrumented indentation reveal that the indentation sti€ness depends on the material condition (i.e. poled vs unpoled) and the type of indentor (i.e. electrically conducting vs insulating). Good agreement was found b...