Thin shells are found in nature at scales ranging from viruses to hens' eggs; the stiffness of such shells is essential for their function. We present the results of numerical simulations and theoretical analyses for the indentation of ellipsoidal and cylindrical elastic shells, considering both pressurized and unpressurized shells. We provide a theoretical foundation for the experimental findi...

The stiffness and hydraulic permeability of soft contact lenses may influence its clinical performance, e.g., on-eye movement, fitting, and wettability, and may be related to the occurrence of complications; e.g., lesions. It is therefore important to determine these properties in the design of comfortable contact lenses. Micro-indentation provides a nondestructive means of measuring mechanical...

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 study has been made of the deformation field in plane-strain indentation of metals with a flat punch. Deformation field parameters such as velocity and strain rate have been measured using the technique of particle image velocimetry. For this purpose, images of the indentation region were recorded in situ during the deformation process, and motion of ‘asperities’ specially introduced onto a s...

Twenty-four slowly adapting type 1 (SA1) and 26 rapidly adapting (RA) cutaneous mechanoreceptive afferents in the rhesus monkey were studied with an array of independently controlled, punctate probes that covered an entire fingerpad. Each afferent had a receptive field (RF) on a single fingerpad and was studied at 73 skin sites (50 mm2). The entire array was lowered to 1.6 mm below the point of...

Indentation-induced plastic deformation of amorphous silicon (a-Si) thin films was studied by in situ Raman imaging of the deformed contact region of an indented sample, employing a Raman spectroscopy-enhanced instrumented indentation technique. Quantitative analyses of the generated in situ Raman maps provide unique, new insight into the phase behavior of as-implanted a-Si. In particular, the ...

The glabrous skin of the monkey's hand was stimulated with a waveform that indented the skin at a rate of 0.4 mm/sec, held the skin steadily or nearly steadily indented for 12 sec or longer, and then retracted back to the starting position. Recordings were made of activity in single afferent fibers in response to these stimuli. The average discharge frequency of 21 slowly adapting mechanorecept...

Mechanical properties of ZnS nanobelts were measured at room temperature by direct nanoindentation experiments. It was found that the ZnS nanobelts achieve 79% increase in hardness but 52% decrease in elastic modulus compared to bulk ZnS. The nanobelts were found to exhibit creep under indentation. Indentation cracking was preferred along the belt growth direction. Indentation deformation behav...

Multiple length-scale effects are demonstrated in indentation-strength measurements of a range of ceramic materials under inert and reactive conditions. Meso-scale effects associated with flaw disruption by lateral cracking at large indentation loads are shown to increase strengths above the ideal indentation response. Micro-scale effects associated with toughening by microstructural restraints...

Molecular dynamics simulations are used to examine the nanometer-scale indentation of a thin film of amorphous carbon with a nonrigid sp bonded carbon tip. The simulations show in detail the atomic-scale mechanism of the indentation process and compare the bonding character of the film before and after indentation. The computationally determined elastic modulus of the amorphous-carbon film is f...