BACKGROUND Aerospace environments commonly expose pilots to vibration and sustained acceleration, alone and in combination. CASE REPORTS Of 16 experimental research participants, 3 reported symptoms of vertigo and signs of torsional nystagmus during or shortly following exposure to sustained chest-to-spine (+3.8 Gx) acceleration (G loading) and chest-to-spine (0.5 g(x)) vibration in the 8-16 ...

In the manufacturing industry, lots of rapid point-to-point motion is required while the residual vibration is unfavorable. Residual vibrations caused by flexible elements are limiting the performance of mechanical system, especially when the system needs to make rapid point-to-point motion. As proved in earlier studies, avoiding natural frequencies of the mechanical system reduces the residual...

BACKGROUND Assessing past cumulative vibration exposure is part of assessing the risk of hand-arm vibration syndrome (HAVS) in workers exposed to hand-arm vibration and invariably forms part of a medical assessment of such workers. AIMS To investigate the strength of relationships between the presence and severity of HAVS and different cumulative exposure metrics obtained from a self-reportin...

As to the complicated characteristics of overhead working truck under effects of random dynamic wind, the traditional method is difficult to reflect its dynamic response in real time, in the study; it proposes the random wind induced vibration response analysis method based on the finite element method and pseudo-excitation method. An it regards the vibration of the fluctuating wind load as coh...

this study is investigated the optimum parameters for a tuned mass damper (tmd) under the seismic excitation. shuffled complex evolution (sce) is a meta-heuristic optimization method which is used to find the optimum damping and tuning frequency ratio for a tmd. the efficiency of the tmd is evaluated by decreasing the structural displacement dynamic magnification factor (ddmf) and acceleration ...

The whole body vibration from the seat and foot board was measured during ten years from 11 different snowmobiles to evaluate the exposure and the need for technical improvements. In a questionnaire more than half of the drivers had back pains but only a few of them considered the whole body vibration as a health hazard. However in the literature there is often comments on spinal injuries relat...

The objective of the study was evaluation of an annual exposure of private farmers to whole body mechanical vibration on selected family farms of plant production profile. The study covered 15 family farms, using arable land of the size of 10-50 ha (22.3 ha on average), engaged mainly in plant production, and equipped with tractors, tractor-mounted agricultural machinery, with a partial contrib...

This paper presents a new approach for the use of piezoelectric materials, PVDF and PZT, for vibration attenuation of a planar parallel manipulator. Since lightweight linkages of parallel manipulators deform under high acceleration/deceleration, such motion induced vibration would have to be damped quickly to reduce settling time of the platform position. An active damping controller is develop...

in this paper, multi-objective uniform-diversity genetic algorithm (muga) with a diversity preserving mechanism called the ε-elimination algorithm is used for pareto optimization of 5-degree of freedom vehicle vibration model considering the five conflicting functions simultaneously. the important conflicting objective functions that have been considered in this work are, namely, vertical accel...