The study of indentation responses of rate-dependent (viscoplastic or creeping) solids has generally focused on the relationship between indentation hardness and an effective strain rate, which can be defined from a similarity transformation of the governing equations. The strain rate sensitivity exponent can be determined from the slope of a log-log plot of the hardness versus effective strain...

INTRODUCTION: The topographic analysis of cartilage mechanical properties has been of particular interest since it is known that physiological loading patterns differ with location in a synovial joint. Site-specific in vivo material characterization of articular cartilage has previously been performed using both ultrasound and indentation techniques [1-3]. Ultrasound biomicroscopy (UBM) uses hi...

An approach for combined imaging of elastic and electromechanical properties of materials, referred to as piezoacoustic scanning probe microscopy PA-SPM , is presented. Applicability of this technique for elastic and electromechanical imaging with nanoscale resolution in such dissimilar materials as ferroelectrics and biological tissues is demonstrated. The PA-SPM signal formation is analyzed b...

The possibility of a third phase, often referred to as the interphase, in polymer composites is well known, and there have been many attempts to characterise the mechanical properties of this region at the nanoscale. Despite the increasing resolution of nano-indentation and atomic force microscopy techniques, it is not always possible to identify thin interphases when the dimensions are similar...

A systematic study of depth-sensing indentation was performed on nanocrystalline (nc) Ni–W alloys specially synthesized with controlled unidirectional gradients in plastic properties. A yield strength gradient and a roughly constant Young’s modulus were achieved in the nc alloys, using electrodeposition techniques. The force vs. displacement response from instrumented indentation experiments ma...

INSTRUMENTED INDENTATION TESTING (IIT), also known as depth-sensing indentation, continuous-recording indentation, ultra-low-load indentation, and nanoindentation, is a relatively new form of mechanical testing that significantly expands on the capabilities of traditional hardness testing. Developed largely over the past two decades, IIT employs high-resolution instrumentation to continuously c...

Articular cartilage plays an important role in the function of diarthrodial joints. Computational methods have been used to study the biphasic mechanics of cartilage, and Abaqus has been one of the most widely used commercial software packages for this purpose. A newly developed open-source finite element solver, FEBio, has been developed specifically for biomechanical applications. The aim of ...

Hertz contact theory has been widely used for the determination of cell elasticity based on AFM indentation experiments. In light of the adhesive contact between AFM tip and cell, this study applied Johnson-Kendall-Roberts (JKR) model to fit the indentation force-displacement (F-D) curves reported previously. A MIN6 cell has been modeled as first a sphere and then a flattened cell with differen...

Examination of deformation microstructures induced by micro-indentation technique by means of transmission electron microscopy following an MV range metallic ion irradiation was performed in order to study the influence of irradiation-produced microstructural defects on plastic deformation behavior of materials. In this work, specimens of an Fe-Cr-Ni austenitic model ternary alloy before and af...

In order to better exploit the natural cork available in Algeria, an experimental characterisation of a jute/ epoxy–cork sandwich material to impact and indentation was undertaken. The aim of this work is to evaluate the impact energy and cork density influence over the sandwich plate damage behaviours by instrumented static and dynamic tests. The results show that the onset damage force, the m...