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...

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...

A comprehensive study on the spherical indentation of hyperelastic soft materials is carried out through combined theoretical, computational, and experimental efforts. Four widely used hyperelastic constitutive models are studied, including neo-Hookean, Mooney-Rivlin, Fung, and Arruda-Boyce models. Through dimensional analysis and finite element simulations, we establish the explicit relations ...

The strength degrading effects of sharp-contact damage are examined for Y-TZP ceramic plates bonded to a plastic substrate. Contacts are made with Vickers and Berkovich diamond indenters at low loads (0.1 N to 100 N) in the ceramic lower surfaces prior to bonding to the substrates. The indentations remain in the subthreshold region, that is, without visible corner radial cracks, over the lower ...

Colloidal-probe spherical indentation load-relaxation experiments with a probe radius of 3 μm are conducted on poly(ethylene glycol) (PEG) hydrogel materials to quantify their steady-state mechanical properties and time-dependent transport properties via a single experiment. PEG-based hydrogels are shown to be heterogeneous in both morphology and mechanical stiffness at this scale; a linear-har...

BACKGROUND The objectives of this study were to quantify the indentation strength and modulus of distal humeral cancellous bone, and to identify regional variations. The motivations were to assist in prosthesis development and to optimize screw placement. METHODS Three consecutive 3mm transverse slices were sectioned from the distal ends of seven fresh-frozen cadaveric specimens. A 3 x 3mm gr...