We present a dynamically tunable mechanism of wave transmission in one-dimensional helicoidal phononic crystals in a shape similar to DNA structures. These helicoidal architectures allow slanted nonlinear contact among cylindrical constituents, and the relative torsional movements can dynamically tune the contact stiffness between neighboring cylinders. This results in cross-talking between in-...

A novel method, which was called a slope method, has been proposed to measure fluid density by the micro-cantilever sensing chip. The theoretical formulas of the slope method were discussed and established when the micro-cantilever sensing chip was under flexural and torsional vibrations. The slope was calculated based on the fitted curve between the excitation and output voltages of sensing ch...

To study the effect of different parameters on milling force for longitudinal-torsional ultrasonic vibration (LTUM) titanium alloy, kinematic theory LTUM is combined with model transient cutting thickness to establish equation, and experiment was carried out. The experimental results showed that positively correlated speed, depth, feed per tooth (milling increased by about 40% in increasing spe...

As the 2nd report, we present a practical calculation method for torsional vibration of highly damped system with rubber couplings. This calculation system, constructed by a modal analysis technique, outputs frequency response characteristics, forced vibration responses, and mode animations. In respect of a damping model and calculation accuracy, it was verified that the assumption of general v...

Torsional vibrations and resonance problems with synchronous machines are most frequently encountered in rotor systems with long shafts and large inertias constituting a weakly damped mechanical resonator which exhibits a low resonance frequency. It is impossible to obtain a effective mechanical damping for these torsional vibrations, but by using a power electronics device and an inductive or ...

We report the measurement of two new perpendicular (D2O)3 torsional bands by terahertz laser vibration–rotation–tunneling ~VRT! spectroscopy of a planar pulsed supersonic expansion. The first ~28.0 cm) band corresponds to the k562 ←0 transition, and is the lowest frequency vibrational spectrum observed for a water cluster. The second ~81.8 cm) band originates in the first excited torsional stat...

Torsional vibration is an oscillation phenomenon occurring at driven railway vehicle wheelsets. As the resulting dynamic stresses can be significantly larger than maximum static motor torque, axle and press fit are risk of failure. To prevent dangerous events with these, from failure, traction drive manufactures nowadays used to implement suppression algorithms in controls. In this paper, effec...

We study theoretically and experimentally the mechanisms of nonlinear and nonequilibrium dynamics in geomaterials through dynamic acoustoelasticity testing. In the proposed theoretical formulation, the classical theory of nonlinear elasticity is extended to include the effects of conditioning. This formulation is adapted to the context of dynamic acoustoelasticity testing in which a low-frequen...

Many of the papers studying the screw-drive system dynamic model concentrated on the control methodologies that is why vibrational models are either simple lumped models or simplified flexible beam models. In this paper a screw-drive system dynamic model and its vibrations are discussed. The screw is considered as an EulerBernoulli type flexible beam with fixed-free boundary conditions and the ...