Thermal dependency of material characteristics in micro electromechanical systems strongly affects their performance, design, and control. Hence, it is essential to understand and model that in MEMS devices to optimize their designs. A thermal phenomenon introduces two main effects: damping due to internal friction, and softening due to Young modulustemperature relation. Based on some reported ...

Studies of torsional properties of natural silk fibers seem to open a new window in understanding the correlation between their extraordinary mechanical properties and their microscopic structure. In this paper, the torsional relaxation profiles of single-stranded Bombyx mori silk was obtained from our experiment, and a prominent under-damping mode was identified. It was concluded that the sing...

We consider second-order evolution equations in an abstract setting with intermittently delayed/not-delayed damping and give sufficient conditions ensuring asymptotic and exponential stability results. Our abstract framework is then applied to the wave equation, the elasticity system, and the Petrovsky system. For the Petrovsky system with clamped boundary conditions, we further prove an intern...

Micro and nanomechanical resonators with ultra-low dissipation have great potential as useful quantum resources. The superfluid micromechanical resonators presented here possess several advantageous characteristics: straightforward thermalization, dissipationless flow, and in situ tunability. We identify and quantitatively model the various dissipation mechanisms in two resonators, one fabricat...

Cyclic-tension fatigue of aluminum alloy, Al-4Cu-1Mg, was determined by an analysis of diffracted SH and SV waves, passing through the surface and reflecting the bottom of the specimen, respectively. The internal friction of SV waves begins to increase from fatigue damage ratio(=N/Nf) of 0.5. This suggests increase of movable dislocation. From the analysis of SH waves, the logarithmic damping r...

The internal friction of high-purity NiAl single crystals was investigated utilizing a low-frequency subresonance torsion a p m . Above lOOOK the damping increases strongly up to Q-' =0.3 at 1400K. The activation enthalpy of this viscoelastic relaxation depends on the composition and shows the highest value (2.8eV) for stoichiometric NiAl. The results are discussed in terms of diffusionantrolle...

Inertial energy scavengers are self-contained devices which generate power from ambient motion, by electrically damping the internal motion of a suspended proof mass. There are significant challenges in converting the power generated from such devices to useable form, particularly in micro-engineered variants. This paper examines this power conversion requirement for each of the cases of electr...

Magnetorheological dampers (MRDs) use the controlled rheological properties of MRF with action an applied magnetic field to achieve lower current regulation and control larger damping. MRD technology is defense industry, vehicle engineering, civil traffic aerospace, other equipment. In this paper, structural design latest engineering applications three types MRDs including internal, bypass, hyb...

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(x 1 , . . . , x n ) ∈ Rn and t > 0, k 1 > 0 and k 2 > 0 are constants. The nonlinear termf(u) = O(u1+θ) and θ is a positive integer. Equation (1) is a model in variational form for the neoHookean elastomer rod and describes the motion of a neoHookean elastomer rod with internal damping; for more detailed physical background, we refer to [1]. In [1], the authors have studied a general class of ...