Combining several materials (“phases”) into a composite material permits creation of new materials with tunable overall response, e.g., elastic properties, which can be related to the elastic moduli, arrangement, and concentrations of the composite’s phases. A recent advance predicts use of one phase having correctly tuned non-positive-definite elastic moduli (i.e., negative stiffness) in a two...

Background: Adequate passive stiffness of the hip joint can prevent the occurrence of excessive transverse plane lower limb movement during functional activities. Strength training of the hip lateral rotator muscles can be used to increase the stiffness of this joint. However, the relationship between hip joint passive stiffness and muscle strength remains undocumented in the literature. Object...

BACKGROUND Adequate passive stiffness of the hip joint can prevent the occurrence of excessive transverse plane lower limb movement during functional activities. Strength training of the hip lateral rotator muscles can be used to increase the stiffness of this joint. However, the relationship between hip joint passive stiffness and muscle strength remains undocumented in the literature. OBJEC...

We use atomic force microscopy to image grain boundaries and ripples in graphene membranes obtained by chemical vapor deposition. Nanoindentation measurements reveal that out-of-plane ripples effectively soften graphene's in-plane stiffness. Furthermore, grain boundaries significantly decrease the breaking strength of these membranes. Molecular dynamics simulations reveal that grain boundaries ...

The development of local buckling in the web-post and the compressive regions around the openings of cellular beams is often a critical design consideration. The current buckling assessment of such scenario is still based on simplified models, which are calibrated against detailed finite element models only for specific geometries including layout and range of dimensions, Moreover, the direct u...

We have performed micromagnetic simulations of the vortex gyrotropic mode resonance in a range of disk geometries subject to spatially uniform out-of-plane magnetic fields. For disks of small lateral dimensions, we observe a drop-off in the mode’s frequency for field amplitudes approaching the disk saturation field. This non-linear frequency response is shown to be associated with an increased ...

This masonry research investigated the differences in the static and dynamic stiffness for the seismic range of loads and frequencies for a pressed clay masonry wythe. The effective stiffness has been defined in Newtonian physics and Damage Mechanics. This research used the concept of measured stiffness defined as the measured stress field divided by the measured strain field. A two-part test r...