in this paper, the effects of transverse cracks on rotating shaft were studied. according to earlier works, crack shaft failure decrease the critical speed of the shaft and also exhibit a nonlinear vibration behaviour leading to increases the amplitude of 1x and 2x harmonics (first and second order of rotational speed in torsional vibration). this suggests that the application of order analysis...

In this paper, two kinds of vibrations are considered for a composite Timoshenko rotor: longitudinal-torsional vibration and two plane transverse one. The kinetic and potential energies and virtual work due to the gyroscopic effects are calculated and the set of six governing equations and boundary conditions are derived using Hamilton principle. Differential quadrature method (DQM) is used as ...

this study compares the functional capabilities of different metacarpal fixation constructs under physiological loadings in an attempt to identify the optimal construct rather than the strongest one. one hundred and twenty-six preserved human metacarpals were mechanically tested after oblique osteotomies and internal fixation. maximum load to failure, average structural rigidity, and energy abs...

Compliant Actuators are desirable for human friendly robotics, especially for assistive and rehabilitation robots that have direct physical interaction with human users. Various designs of Series Elastic Actuators (SEA) have been developed for these applications. This paper presents a novel SEA design with variable impedance for human-friendly robotics applications that overcomes the major limi...

BACKGROUND AND PURPOSE Zoledronic acid (ZOL) has been shown in vitro and in vivo to inhibit osteoclastic activity and to regulate osteoblasts. Its antiresorptive effect is used clinically in the treatment of bone-consuming pathologies to prevent skeletal complications. Because of its effect on bone cells, there might be a possible benefit in treatment of fractures by local application from a bi...

Turbomachinery shafting and casings typically experience axial growth during thermal transients occurring at startup, shutdown, and changes of load. This growth does not usually present difficulties during operation. However, this paper discusses four recent turbomachinery trains that experienced radial subsynchronous vibration resulting from axial misalignment. In each example, the train inclu...

The demand for accurate and reliable positioning in industrial applications, especially in robotics and high-precision machines, has led to the increased use of Harmonic Drives. The unique performance features of harmonic drives, such as high reduction ratio and high torque capacity in a compact geometry, justify their widespread application. However, nonlinear torsional compliance and friction...

Electrical drives for large capacity compressors in a liquefied natural gas (LNG) plant have been investigated. There are mainly two topologies for such an electrical drive; load commutated inverters (LCIs) and voltage source inverters (VSIs). Due to commutation of the thyristors, LCIs produce current harmonics with variable frequencies, and their interharmonics are significant. Therefore, tors...

Two novel devices, torsional actuator and torsional stepper motor, are described and their performance is investigated in detail. Both devices were designed to produce large angular displacement and large torque output from the piezoelectric d15 shear response. In the torsional actuator, the large displacement can be achieved due to built-in amplification of piezoelectric strain using the aspec...