Apparent mass and head vibration transmission responses of seated body to three translational axis vibration

Mandapuram, Santosh; Rakheja, Subhash; Boileau, P.-É.; Maeda, Setsuo

doi:10.1016/j.ergon.2012.02.002

Cited by 38 publications

(26 citation statements)

References 28 publications

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“…The power along an individual axis, however, is similar to that obtained under single-axis of vibration. This is caused by the relatively small coupling effect of multi-axis vibration, as reported in the APMS responses [27,28].…”

Section: Discussionmentioning

confidence: 99%

“…The cross-axis responses under single axis vibration do not contribute to the VPA, since the cross-axis force component and the applied excitation are in the orthogonal directions. Under three-axis vibration, however, the total apparent mass measured along a given axis i also incorporates the cross-axis force components caused by vibration along axis j (i ≠ j) [28]. The resultant force measured along axis i can thus be related to sum of the direct and cross-axis force components, such that:…”

Section: Analyses Of Absorbed Power Responses To Three-axis Vibrationmentioning

confidence: 99%

“…Under three-axis vibration, the VPA measured along each vibration axis is thus expected to differ from that measured under the individual axis vibration. Owing to the uncorrelated nature of the three-axis vibration employed in the study, the APMS responses of the body exposed to three-axis vibration were derived using the H v frequency response function estimator [28]: (6) In the above equation, M i defines the complex APMS response along axis i (i = x, y, z), S aiFi ( f ) is the cross spectrum of total force F i and excitation a i along axis i, and S Fi ( f ) and S ai ( f ) are the auto-spectra of the total force response and acceleration excitation along i under multi-axis vibration. The APMS responses of the seated body were derived from the forces measured at both the seat pan and the backrest (when used).…”

Section: Analyses Of Absorbed Power Responses To Three-axis Vibrationmentioning

confidence: 99%

“…The lack of the coupling effects in the data was attributed to the use of the H 1 frequency response function estimator based on crossspectral density (CSD) of the response and excitation that suppressed the contribution of cross-axis responses under uncorrelated multi-axis vibration [29]. A recent study has suggested an alternate frequency response function (H v ) method to analyse seated body responses to uncorrelated multi-axis vibration and revealed notable coupling effects of multi-axis vibration in the driving-point and transmissibility responses, particularly in the sagittal plane [27,28]. The total VPA of the body exposed to multi-axis vibration is thus expected to differ from the reported characteristics under single-axis vibration, which have not been investigated thus far.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Energy Absorption of Seated Body Exposed to Single and Three-Axis Whole Body Vibration

Mandapuram

Rakheja

Boileau

et al. 2015

Journal of Low Frequency Noise, Vibration and Active Control

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The absorbed power characteristics of seated body exposed to whole-body vibration along the individual and combined fore-aft (x), lateral (y) and vertical (z) axes are investigated through measurements of body-seat interactions at the two driving-points formed by the body and the seat-pan, and upper body and the seat backrest. The experiments involved two levels of back support (no back support and vertical backrest) and two levels of broad-band vibration with nearly constant acceleration power spectral density in the 0.5-20 Hz frequency range applied along the individual x-, y-and z-axis (0.25 and 0.4 m/s 2 rms acceleration), and along the three-axis (0.23 and 0.4 m/s 2 rms acceleration along each axis). The biodynamic responses, measured at the seat-pan and the backrest are applied to characterize the total seated body's energy transfer along each axis. Furthermore, an alternative frequency response function method H v is employed to capture the coupling in the seated body responses to uncorrelated multi-axis vibration. The total vibration absorbed power responses to simultaneous x, y and z -axis vibration are subsequently derived as the summation of vibration absorbed power along the individual axis within each one-third frequency band. The mean responses measured at the seat-pan suggest strong effects of the back support, and the direction and magnitude of vibration. The total vibration power absorbed by the seated body is further estimated under a multi-axis vibration environment of four different work vehicles. The results suggest that total average power absorbed under reported vehicular vibration varies with the effective acceleration in a nearly quadratic manner.

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Section: Discussionmentioning

confidence: 99%

Section: Analyses Of Absorbed Power Responses To Three-axis Vibrationmentioning

confidence: 99%

Section: Analyses Of Absorbed Power Responses To Three-axis Vibrationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Energy Absorption of Seated Body Exposed to Single and Three-Axis Whole Body Vibration

Mandapuram

Rakheja

Boileau

et al. 2015

Journal of Low Frequency Noise, Vibration and Active Control

Self Cite

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“…where a head (f ) is acceleration at the head, and a seat (f ) acceleration at the seat. A large number of experimental studies 6,7,11,17,18,21,22,25 have focused on the transmissibility of vibration to various parts of the human body, such as seat-to-head, pelvis, lumber/cervical, etc., with a broad range of experimental conditions. Griffin and Whitham have observed the significant effect of individual variability on transmissibility of WBV through the seated subjects.…”

Section: Introductionmentioning

confidence: 99%

Seat-to-Head Transmissibility and Reading\\ Discomfort of the Seated Subjects Exposed to Whole Body Vibration

Kumara¹,

Saran²

2016

IJAV

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The transmission of vibration from the vibrating interface to various organs of the human body may influence their functioning during the vibration exposure. Therefore, an experimental study on a vibration simulator has been performed to find the effects of vibration on reading performance, and also to establish the relationship between seat-to-head transmissibility (STHT) with reading difficulty and reduction in reading performance. Twelve seated male subjects were exposed to sinusoidal vibration with three magnitudes (0.5, 1.0 & 1.5 m/s2 rms) at seven different frequencies (4, 5, 6.3, 10, 16, 20, and 25 Hz) in three independent directions (vertical, fore-and-aft, and lateral). The results show that three output measures-STHT, reduction in reading performance, and perceived difficulty in reading-are significantly affected by the frequency of vibration in each direction. All three measures have shown the peak at 4 or 5 Hz in three independent directions of vibration. Another peak at 25 Hz has also been observed for reduction in performance and perceived reading difficulty in vertical direction vibration. The results also show decrease in resonance frequency of the transmissibility with an increase in vibration magnitude, which represents nonlinear behaviour in biodynamic response by the human body.

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Prediction of the biomechanical behaviour of the lumbar spine under multi‐axis whole‐body vibration using a whole‐body finite element model

Zhang

Guo

2023

Numer Methods Biomed Eng

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Low back pain has been reported to have a high prevalence among occupational drivers. Whole‐body vibration during the driving environment has been found to be a possible factor leading to low back pain. Vibration loads might lead to degeneration and herniation of the intervertebral disc, which would increase incidence of low back problems among drivers. Some previous studies have reported the effects of whole‐body vibration on the human body, but studies on the internal dynamic responses of the lumbar spine under multi‐axis vibration are limited. In this study, the internal biomechanical response of the intervertebral disc was extracted to investigate the biomechanical behaviour of the lumbar spine under a multi‐axial vibration in a whole‐body environment. A whole‐body finite element model, including skin, soft tissues, the bone skeleton, internal organs and a detailed ligamentous lumbar spine, was used to provide a whole‐body condition for analyses. The results showed that both vibrations close to vertical and fore‐and‐aft resonance frequencies would increase the transmission of vibrations in the intervertebral disc, and vertical vibration might have a greater effect on the lumbar spine than fore‐and‐aft vibration. The larger deformation of the posterior region of the intervertebral disc in a multi‐axis vibration environment might contribute to the higher susceptibility of the posterior region of the intervertebral disc to injury. The findings of this study revealed the dynamic behaviours of the lumbar spine in multi‐axis vehicle vibration conditions, and suggested that both vertical and fore‐and‐aft vibration should be considered for protecting the lumbar health of occupational drivers.

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Apparent mass and head vibration transmission responses of seated body to three translational axis vibration

Cited by 38 publications

References 28 publications

Energy Absorption of Seated Body Exposed to Single and Three-Axis Whole Body Vibration

Energy Absorption of Seated Body Exposed to Single and Three-Axis Whole Body Vibration

Seat-to-Head Transmissibility and Reading\\ Discomfort of the Seated Subjects Exposed to Whole Body Vibration

Prediction of the biomechanical behaviour of the lumbar spine under multi‐axis whole‐body vibration using a whole‐body finite element model

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