Non-linear dual-axis biodynamic response to vertical whole-body vibration

Nawayseh, Naser; Griffin, Michael J.

doi:10.1016/s0022-460x(03)00254-2

Cited by 85 publications

(68 citation statements)

References 21 publications

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“…Kitazaki [30] found that the resonance frequencies of the feet decreased from 9, 13, and 35 Hz to 8, 12 and 33 Hz when the magnitude of vertical vibration increased from 0.3 to 1.0 ms -2 r.m.s. A similar non-linearity in the apparent mass at the feet has been reported with both vertical vibration of the feet [35] and fore-and-aft vibration of the feet [36] during simultaneous exposure to the same axis of vibration at the seat: with both axes, increases in the vibration magnitude decreased the principal resonance frequency of the apparent mass. The magnitude-dependence of the equivalent comfort contours at high frequencies (i.e.…”

Section: Fig 8 About Heresupporting

confidence: 71%

Magnitude-dependence of equivalent comfort contours for fore-and-aft, lateral, and vertical vibration at the foot for seated persons

Morioka

Griffin

2010

Journal of Sound and Vibration

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Section: Fig 8 About Heresupporting

confidence: 71%

Magnitude-dependence of equivalent comfort contours for fore-and-aft, lateral, and vertical vibration at the foot for seated persons

Morioka

Griffin

2010

Journal of Sound and Vibration

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“…Raising the height of a seat pan relative to the feet increases the apparent mass at resonance, due to more mass being supported on the seat surface [9,12]. A slight increase in the apparent mass at resonance has been observed if the feet are moved forward, possibly as a result of more mass being supported on the seat surface, however only a small range of foot movement (150 mm) has been investigated [8].…”

Section: Introductionmentioning

confidence: 99%

Apparent mass of the human body in the vertical direction: Effect of a footrest and a steering wheel

Toward

Griffin

2010

Journal of Sound and Vibration

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The apparent mass of the seated human body influences the vibration transmitted through a car seat. The apparent mass of the body is known to be influenced by sitting posture but the influence of the position of the hands and the feet is not well understood. This study was designed to quantify the influence of steering wheel location and the position of a footrest on the vertical apparent mass of the human body. The influences of the forces applied by the hands to a steering wheel and by the feet to a footrest were also investigated. Twelve subjects were exposed to whole-body vertical random vibration (1.0 ms Moving the steering wheel away from the body reduced the apparent mass at the primary resonance frequency and increased the apparent mass around the 4 Hz resonance. As the feet moved forward, the mass supported on the seat surface decreased, indicating that the backrest and footrest supported a greater proportion of the subject weight. Applying force to either the steering wheel or the footrest reduced the apparent mass at resonance and decreased the mass supported on the seat surface. It is concluded that the positions and contact conditions of the hands and the feet affect the biodynamic response of the body in a car driving posture. As the biodynamic response influences the vibration transmitted through seats, these factors should be considered in dynamic models of vehicle seating.

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“…Recent studies have attempted to categorize the possible mechanisms of injury related to WBV [6][7][8][9][10][11] and develop models that could optimize preventive measures [12][13][14][15]. Although none of these investigators addresses the effects of WBV on wheelchair users, their conclusions may be used to improve wheelchair design and research.…”

Section: Introductionmentioning

confidence: 99%

Curb descent testing of suspension manual wheelchairs

Kwarciak

Cooper²,

Fitzgerald³

2008

JRRD

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Abstract-Manual wheelchair users are subjected to wholebody vibrations (WBV) on a regular basis as they traverse obstacles and uneven surfaces. One way users could protect themselves from secondary injuries related to WBV is by using a suspension manual wheelchair. This study investigated the ability of suspension manual wheelchairs to reduce seat accelerations during curb descents of various heights (5, 10, and 15 cm). Sixteen manual wheelchairs (four suspension, four folding, four rigid, and four rigid titanium) were tested. Suspension wheelchairs transmitted significantly lower peak seat accelerations than folding wheelchairs during the 5 cm curb descents (p = 0.048) and significantly lower frequencyweighted peak seat accelerations during the 5 and 10 cm curb descents (p = 0.03 for both heights). However, when the suspension wheelchair Quickie XTR (Sunrise Medical; Carlsbad, California) was removed from the analysis, the suspension wheelchairs were not significantly different from the nonsuspension wheelchairs. When weight was considered, the suspension wheelchairs had significantly lower peak seat accelerations than the lighter rigid wheelchairs during 5 cm curb descents (p = 0.047). While suspension manual wheelchairs offer some reduction in WBV during curb descents, their limitations should be considered when a wheelchair is selected for everyday use.

show abstract

Non-linear dual-axis biodynamic response to vertical whole-body vibration

Cited by 85 publications

References 21 publications

Magnitude-dependence of equivalent comfort contours for fore-and-aft, lateral, and vertical vibration at the foot for seated persons

Magnitude-dependence of equivalent comfort contours for fore-and-aft, lateral, and vertical vibration at the foot for seated persons

Apparent mass of the human body in the vertical direction: Effect of a footrest and a steering wheel

Curb descent testing of suspension manual wheelchairs

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