Apparent Mass and Seat-to-head Transmissibility Responses of Seated Occupants under Single and Dual Axis Horizontal Vibration

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

doi:10.2486/indhealth.mswbvi-15

Cited by 21 publications

(35 citation statements)

References 24 publications

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“…Since the VPA is computed from the APMS responses, the inter-subject variability of the VPA data was identical to that obtained for the APMS responses reported in [26]. The maximum coefficient of variations of the VPA for the back supported (B0) and unsupported (NB) conditions and the excitations considered, ranged from 15-30%, in the vicinity of the primary resonant frequency, which are comparable to those reported under single axis vibration [17,19].…”

Section: Journal Of Low Frequency Noise Vibration and Active Control 26supporting

confidence: 67%

“…The forces along the three translational axes at the two body-seat interfaces (buttocks-seat pan and the upper body-backrest) were measured when exposed to single as well as three-axis whole-body vibration. The experimental setup used in this study was identical to that used for characterization of apparent mass and reported in [26,27]. Briefly, a rigid seat and a steering column were installed on a 6-DOF whole-body vibration simulator (IMV Corp.) at the National Institute of Occupational Safety and Health, Japan.…”

Section: Methodsmentioning

confidence: 99%

“…In the absence of the backrest, the force measured at the seat pan alone was used to compute the APMS. In case of the back support, the total APMS was derived upon summation of those computed from the forces at the seat pan and the backrest, such that [26]: (7) where M pi and M bi are the complex APMS responses measured at the seat pan and the backrest, respectively, along axis i.…”

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

confidence: 99%

“…These studies have provided important insights into vibration modes and resonances of the seated body, and the effects of the body supports and intensity of vibration. similar to those under single axis vibration, even though the subjects experienced substantial coupled motions [24][25][26]. 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].…”

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: Journal Of Low Frequency Noise Vibration and Active Control 26supporting

confidence: 67%

Section: Methodsmentioning

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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show abstract

“…The video-based displacements and accelerometer data were used separately to compute the transmissibility of the thoracic spine at each input frequency [30,42,52,68]. The accelerometer data were filtered using a fifth-order Butterworth bandwidth filter and the root mean square (RMS) acceleration of the thoracic accelerometer was divided by the platform acceleration to compute accelerometer-based transmissibility at each frequency.…”

Section: Wbv Transmissibility and Resonancementioning

confidence: 99%

Whole-body Vibration at Thoracic Resonance Induces Sustained Pain and Widespread Cervical Neuroinflammation in the Rat

Zeeman

Kartha

Jaumard

et al. 2015

Clinical Orthopaedics &Amp; Related Research

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Background Whole-body vibration (WBV) is associated with back and neck pain in military personnel and civilians. However, the role of vibration frequency and the physiological mechanisms involved in pain symptoms are unknown. Questions/purposes This study asked the following questions: (1) What is the resonance frequency of the rat spine for WBV along the spinal axis, and how does frequency of WBV alter the extent of spinal compression/ extension? (2) Does a single WBV exposure at resonance induce pain that is sustained? (3) Does WBV at resonance alter the protein kinase C epsilon (PKCe) response in the dorsal root ganglia (DRG)? (4) Does WBV at resonance alter expression of calcitonin gene-related peptide (CGRP) in the spinal dorsal horn? (5) Does WBV at resonance alter the spinal neuroimmune responses that regulate pain? Methods Resonance of the rat (410 ± 34 g, n = 9) was measured by imposing WBV at frequencies from 3 to 15 Hz. Separate groups (317 ± 20 g, n = 10/treatment) underwent WBV at resonance (8 Hz) or at a nonresonant frequency (15 Hz). Behavioral sensitivity was assessed throughout to measure pain, and PKCe in the DRG was quantified as well as spinal CGRP, glial activation, and cytokine levels at Day 14. Results Accelerometer-based thoracic transmissibility peaks at 8 Hz (1.86 ± 0.19) and 9 Hz (1.95 ± 0.19, mean difference [MD] 0.290 ± 0.266, p \ 0.03), whereas the video-based thoracic transmissibility peaks at 8 Hz (1.90 ± 0.27), 9 Hz (2.07 ± 0.20), and 10 Hz (1.80 ± 0.25, MD 0.359 ± 0.284, p \ 0.01). WBV at 8 Hz produces more cervical extension (0.745 ± 0.582 mm, MD 0.242 ± 0.214, p \ 0.03) and compression (0.870 ± 0.676 mm, MD 0.326 ± 0.261, p \ 0.02) than 15 Hz (extension, 0.503 ± 0.279 mm; compression, 0.544 ± 0.400 mm). Pain is longer lasting (through Day 14) and more robust (p \ 0.01) after WBV at the resonant frequency (8 Hz) compared with 15 Hz WBV. PKCe in the nociceptors of the DRG increases according to the severity of WBV with greatest increases after 8 Hz WBV (p \ 0.03). However, spinal CGRP, cytokines, and glial activation are only evident after painful WBV at resonance. Conclusions WBV at resonance produces long-lasting pain and widespread activation of a host of nociceptive and neuroimmune responses as compared with WBV at a nonresonance condition. Based on this work, future investigations into the temporal and regional neuroimmune response to resonant WBV in both genders would be useful.

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Real‐time vibration monitoring and analysis of agricultural tractor drivers using an IoT‐based system

Singh

Nawayseh

Samuel

et al. 2023

Journal of Field Robotics

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Agricultural tractor drivers experience a high amplitude of vibration, especially during soil tillage operations. In the past, most research studied vibration exposure with more focus on the vertical (z) axis than on the fore‐and‐aft (x) and lateral (y) axes. This study examines how rotary soil tillage affects the vibration acceleration and frequency, and the power spectral densities (PSDs) at the seat pan and head along three translational axes in a real‐field multiaxis vibration context. Moreover, this study aimed to identify the characteristics of the seat‐to‐head transmissibility (STHT) response to identifying the most salient resonant frequencies along the x‐, y‐, and z‐axes. Nine (9) male tractor drivers operated the tractor with a mounted rotary tiller throughout the soil tillage process. In the event of a COVID‐19 pandemic, and to respect social distancing, this study developed an Internet of Things (IoT) module with the potential to integrate with existing data loggers for online data transmission and to make the experimentation process more effective by removing potential sources of experimenter errors. The raw acceleration data retrieved at the seat pan and the head were utilized to obtain daily exposure (A(8)), PSDs, and STHT along the x‐, y‐, and z‐axes. The vibration energy was found to be dominant along the z‐axis than the x‐ and y‐axes. A(8) response among tractor drivers exceeds the exposure action value explicitly stated by Directive 2002/44/EU. PSDs along the x‐, y‐, and z‐axes depicted the low‐frequency vibration induced by rotary soil tillage operation. The STHT response exhibited a higher degree of transmissibility along the y‐ and z‐axes when compared with that along the x‐axis. The frequency range of 4–7 Hz may plausibly be associated with cognitive impairment in tractor drivers during rotary soil tillage.

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Apparent Mass and Seat-to-head Transmissibility Responses of Seated Occupants under Single and Dual Axis Horizontal Vibration

Cited by 21 publications

References 24 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

Whole-body Vibration at Thoracic Resonance Induces Sustained Pain and Widespread Cervical Neuroinflammation in the Rat

Real‐time vibration monitoring and analysis of agricultural tractor drivers using an IoT‐based system

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