Viscoelastic mechanical properties of biological cells are commonly measured using atomic force microscope (AFM) dynamic indentation with spherical tips. A semiempirical analysis based on numerical simulation is built to determine the cell mechanical properties. It is shown that the existing analysis cannot reflect the accurate values of cell elastic/dynamic modulus due to the effects of substr...

Measurement of the strength of brittle materials, such as resin composites, is extremely difficult. Micro-indentation hardness testing is a convenient way of investigating the mechanical properties of a small volume of material. In this study, the mechanical properties of five commercially available flowable resin composites were investigated by the dynamic micro-indentation method. Additionall...

Due to the nature of their material properties, Calcium Fluoride (CaF2), Magnesium Fluoride (MgF2), and Potassium Dihydrogen Phosphate (KDP) are widely used for industrial purposes. A better understanding of the mechanical properties of these materials is of technological and scientific importance. The indentation nano-mechanical response of CaF2 (cubic), MgF2 (tetragonal), and KDP (tetragonal)...

An instrumented indentation method is developed for generating maps of time-dependent viscoelastic and time-independent plastic properties of polymeric materials. The method is based on a pyramidal indentation model consisting of two quadratic viscoelastic Kelvin-like elements and a quadratic plastic element in series. Closed-form solutions for indentation displacement under constant load and c...

BACKGROUND To evaluate the effect of Nd:YAG capsulotomy for posterior capsular opacification (PCO) on visualisation of the peripheral fundus with scleral indentation. METHODS Patients undergoing Nd:YAG capsulotomy for PCO were examined pre- and four weeks post- Nd:YAG capsulotomy. In order to give a quantitative measure of visualisation of the peripheral retina, a novel scalar measurement was...

ADVANCED MATERIALS & PROCESSES • APRIL 2012 I n 1925 in the UK, Smith and Sandland developed an indentation test that used a squarebased pyramidal-shaped indenter made of diamond[1]. The test was developed because the Brinell test (introduced in 1900), which (until recently) used a round hardened steel ball indenter, could not test steels harder than ~450 HB (~48 HRC). They chose this shape wit...

− The method called instrumented indentation test (IIT) emerged as a technique capable to characterise several materials in nanoscale, like nanostructural material, thin film, ceramic material, etc., independently of hardness. The acceptation of this new technique requires, of course, reliable test results where, one of the way to obtain this confidence is to knowing the sources of the testing ...

In this review, we compare the reported values of Young's modulus (YM) obtained from indentation and tensile deformations of soft biological tissues. When the method of deformation is ignored, YM values for any given tissue typically span several orders of magnitude. If the method of deformation is considered, then a consistent and less ambiguous result emerges. On average, YM values for soft t...

The mechanical behavior of graphene under various indentation depths, velocities, and temperatures is studied using molecular dynamics analysis. The results show that the load, elastic and plastic energies, and relaxation force increased with increasing indentation depth and velocity. Nanoindentation induced pile ups and corrugations of the graphene. Resistance to deformation decreased at highe...

For very shallow indentations in W, Al, Au, and Fe-3wt%Si single crystals, hardness decreased with increasing depth irrespective of increasing or decreasing strain gradients. As such, strain gradient theory appears insufficient to explain the indentation size effect (ISE) at depths less than several hundred nanometers. Present research links the ISE to a ratio between the energy of newly create...