Apparent Mass and Absorbed Power During Exposure to Whole-Body Vibration and Repeated Shocks

Mansfield, Neil J.; Holmlund, P.; Lundström, Ronnie

doi:10.1006/jsvi.2001.3796

Cited by 25 publications

(29 citation statements)

References 16 publications

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“…This phenomenon is known as a 'softening effect'. The softening effect can also be observed in the absorbed power 28,32) (Fig. 7).…”

Section: Example Impedance Data From the Literaturementioning

confidence: 73%

“…For whole-body vibration, important contributions have been made by many, including: Fairley 21,22) , Holmlund 18,[23][24][25][26] , Mansfield 16,19,[27][28][29][30][31][32] , Matsumoto 33,34) , Miwa 35) , Nawayseh 36,37) , Rakheja [38][39][40][41][42] , and Smith 43,44) . Although contributions have been made by many individuals, example data presented here will be sourced primarily from the author's own work due to availability of raw data and knowledge of all experimental conditions.…”

Section: Example Impedance Data From the Literaturementioning

confidence: 99%

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Impedance Methods (Apparent Mass, Driving Point Mechanical Impedance and Absorbed Power) for Assessment of the Biomechanical Response of the Seated Person to Whole-body Vibration

Mansfield

2005

Ind Health

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Exposure to whole-body vibration is a risk factor for the development of low back pain. In order to develop a fuller understanding of the response of the seated person to vibration, experiments have been conducted in the laboratory investigating the biomechanics of the seated person. Some of these methods are based on the driving force and acceleration at the seat and are reported in the literature as apparent mass, driving point mechanical impedance or absorbed power. This paper introduces the background behind such impedance methods, the theory and application of the methods. It presents example data showing typical responses of the seated human to wholebody vibration in the vertical, fore-and-aft and lateral directions. It also highlights problems that researchers might encounter in performing, analysing and interpreting human impedance data.

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“…This phenomenon is known as a 'softening effect'. The softening effect can also be observed in the absorbed power 28,32) (Fig. 7).…”

Section: Example Impedance Data From the Literaturementioning

confidence: 73%

Section: Example Impedance Data From the Literaturementioning

confidence: 99%

Impedance Methods (Apparent Mass, Driving Point Mechanical Impedance and Absorbed Power) for Assessment of the Biomechanical Response of the Seated Person to Whole-body Vibration

Mansfield

2005

Ind Health

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“…The absorbed power responses of the seated human body exposed to vertical WBV, have been investigated under continuous sinusoidal and random vibration considering both supported and unsupported back postures [20][21][22][23][24][25] . The P Abs has been related to APMS and DPMI 26) , and the reported P Abs spectra generally exhibit peaks at frequencies that are comparable to those corresponding to APMS/DPMI magnitude peaks.…”

mentioning

confidence: 99%

“…The studies have also shown important influences of variations in the sitting posture and seat geometry factors (seat height, footrest position, hands position, backrest and seat pan angle) on the P Abs response of human occupants exposed to vertical WBV 21,22) . Relatively larger magnitudes of absorbed power have been associated with mechanical shock stimuli compared to the continuous vibration, suggesting greater sensitivity of the human body response to shocks 20) .…”

mentioning

confidence: 99%

Energy Absorption of Seated Occupants Exposed to Horizontal Vibration and Role of Back Support Condition

Rakheja¹,

Mandapuram²,

Dong

2008

Ind Health

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Occupational off road vehicle drivers are exposed to considerable magnitudes of whole-body vibration (WBV), which is known to cause discomfort, annoyance, and several health and safety risks. Many studies have suggested strong association between the exposure to WBV and low back pain 1,2) . The vast majority of the studies on human responses to vibration have emphasized the exposure to vertical WBV, since heavy on-road and off-road vehicles are believed to transmit relatively higher magnitudes of vertical vibration than those along the other axes. Such vehicles, however, also transmit substantial magnitudes of horizontal vibration (HV) along the fore-aft and

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“…Only the largest child, subject SA, exhibited a dynamic response which might suggest two whole-body resonances as found for seated adult humans by , Griffin (1998) andMansfield et. al.…”

Section: Discussionmentioning

confidence: 53%

Absorbed power of small children

Giacomin

2005

Clinical Biomechanics

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Ab stractObjective: To experimentally measure the seated vertical direction whole-body absorbed power characteristics of small children less than 18 kg in mass.Background: Several studies have reported whole-body absorbed power for adult humans, but no data has been published previously for small children.Methods: Eight children were tested in a laboratory test rig which incorporated safety features which satisfy existing international standards for human testing. Force and acceleration were measured at the point of input to a rigid seat at a sampling rate of 200 Hz, and analysis was performed over the interval from 1.0 to 45.0 Hz. A double normalised (both input acceleration and test subject mass) measure of absorbed power was used.Results: The vertical whole-body power absorption characteristics of the small children were found to present differences with respect to those of adults. The mean frequency of peak absorption was found to be 7.4 Hz as opposed to approximately 4.0 to 5.0 for adults. The interval of absorption was found to be from approximately 3 to 16 Hz and the total double normalised absorbed power was found to be 86% that of adults. Conclusions:The differences in dynamic response between small children and adults raise questions regarding the applicability of whole-body vibration guidelines such as ISO-2631 in the case of small children since these guidelines were developed from mechanical and subjective response data of adults. 2 RelevanceKnowledge of the differences in whole-body vibration response between small children and adults is useful towards the design of systems intended for children such as child seats. The child data may also prove useful should absorbed power find application as a screening tool in clinical settings.

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Apparent Mass and Absorbed Power During Exposure to Whole-Body Vibration and Repeated Shocks

Cited by 25 publications

References 16 publications

Impedance Methods (Apparent Mass, Driving Point Mechanical Impedance and Absorbed Power) for Assessment of the Biomechanical Response of the Seated Person to Whole-body Vibration

Impedance Methods (Apparent Mass, Driving Point Mechanical Impedance and Absorbed Power) for Assessment of the Biomechanical Response of the Seated Person to Whole-body Vibration

Energy Absorption of Seated Occupants Exposed to Horizontal Vibration and Role of Back Support Condition

Absorbed power of small children

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