Mechanical properties and deformation of the vertically aligned carbon nanotube arrays (VA-CNTs) has been examined with large-displacement indentation tests inside a scanning electronic microscope (SEM). The in-situ indentation allows for establishment of the load-depth responses and real-time observations of the deformation processes. Under a cylindrical, flat indenter, the VA-CNTs exhibit ela...

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...

Multimillion-atom molecular dynamics simulation of indentation of nanocrystalline silicon carbide reveals unusual deformation mechanisms in brittle nanophase materials, resulting from the coexistence of brittle grains and soft amorphous grain boundary phases. Simulations predict a crossover from intergranular continuous deformation to intragrain discrete deformation at a critical indentation de...

An extant tissue indentor used for amputee residual limb tissue indentation studies was modified to include laser Doppler flowmetry (LDF) to enable measurement of tissue perfusion during indentation. This device allows quantitative assessment of the mechanical and physiological response of soft tissues to load, as demonstrated by indentation studies of the lower-limb tissues of young healthy su...

Previous work by Au, Lucas, Sheckerd & Odette [1] and Haggag and Lucas [2] and others showed that ball indentation testing techniques can be used to evaluate flow properties. More recently Haggag et al [3] have extended and refined the general approach. This work is aimed at assessing the accuracy and reliability of this method based on finite element analysis (FEA) simulations of the ball inde...

We derive an expression relating the axial load, the indentation depth, and the elastic constants of an orthotropic material, and simplify it to that for a cubic material (e.g., an FCC single crystal). We use this formula and results of three virtual (i.e., numerical) indentation tests on the same specimen oriented differently to find values of the elastic moduli, and show that they agree well ...

The abstract should be a single paragraph in block format (without paragraph indentation) and should not exceed 120 words. See section 1.07 of the APA manual (American Psychological Association [APA], 2001) for additional information. The abstract is simply a summary of the paper. One trick in writing the abstract is to write one summary sentence for each major part of the paper. Then you will ...

A physical deduction of the FN = kh 3/2 relation (where FN is normal force, k penetration resistance and h penetration depth) for conical/pyramidal indentation loading curves has been achieved on the basis of elementary mathematics. The indentation process couples the productions of volume and pressure to the displaced material that often partly plasticizes due to such pressure. As the pressure...

Interactions with the physical world are deeply rooted in our sense of touch and depend on ensembles of somatosensory neurons that invade and innervate the skin. Somatosensory neurons convert the mechanical energy delivered in each touch into excitatory membrane currents carried by mechanoelectrical transduction (MeT) channels. Pacinian corpuscles in mammals and touch receptor neurons (TRNs) in...

Static indentation tests on carbon fibre reinforced laminates have been frequently used in literature to predict the value of penetration energy for the laminate. The mechanical set-up most commonly employed involves the use of indentors of diameter comparable with that of the impactors prescribed from standards for falling weight impact, such as ASTM D3763.The specimen is simply supported usin...