In the present study, numerical simulations of the ow in a three-dimensional axisymmet-ric poppet valve are conducted using a vortex method. The uids are assumed inviscid and incompressible. The vibration of the poppet, supported by a spring and a dash pot, occurs in the axial direction in some range of parameters. The numerical simulations are carried out by varying systematically the paramete...

in this paper, chaotic motion analysis and its control for a non-planar non-linear cantilever beam with axial and lateral parametric excitation in the free end is accomplished. this is a new method for control of chaotic motion of a non-linear planar beam. in this survey, internal resonance of the beam is 2:1 and the initial resonance is in the outside of plane and it is assumed a sub-resonance...

Lattice structures are presented with a piezoelectric sensitivity, d, much larger in magnitude than that of material comprising the lattice ribs. Large sensitivity is achieved by using piezoelectric bimorph elements as ribs; these bend in response to electric input, giving rise to a much larger displacement than for axial elements. Complex electrical connectivity is helpful but not necessary; s...

STUDY DESIGN Experiments were undertaken to determine the degree to which high-frequency (15-35 Hz) ground-based, whole-body vibration are transmitted to the proximal femur and lumbar vertebrae of the standing human. OBJECTIVES To establish if extremely low-level (<1 g, where 1 g = earth's gravitational field, or 9.8 ms-2) mechanical stimuli can be efficiently delivered to the axial skeleton ...

purpose: to evaluate the effect of childhood corneal opacity on the anteroposterior length of the globe in adulthood. methods: twenty-three patients with significant unilateral corneal opacity which had developed before the age of 6 years and the normal fellow eyes (controls) were evaluated. a comprehensive ocular examination including measurement of anterioposterior length and anterior chamber...

The nonlinear dynamic model of rotor-bearing-seal system with crack in shaft is set up based on the coupling model of nonlinear oil-film force and Muszyska’s nonlinear seal fluid force. The dynamic vibration characteristics of the rotor-bearing-seal system and the effects of physical and structural parameters of labyrinth seal and crack fault on movement character of the rotor were analyzed. Th...

Experimental modal analysis is a non-destructive measurement technique, which applies low forces and small deformations to assess the integrity of a structure. It is therefore a promising method to study the mechanical properties of the spine in vivo. Previously, modal parameters successfully revealed artificially induced spinal injuries. The question remains however, whether experimental modal...