Objective and subjective responses of seated subjects while reading Hindi newspaper under multi axis whole-body vibration

Bhiwapurkar, Mahesh; Saran, V. H.; Harsha, S. P.

doi:10.1016/j.ergon.2011.06.004

Cited by 17 publications

(11 citation statements)

References 11 publications

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“…This implies that the motion of head is cross coupled for X-axis seat excitation and is more pronounced in backrest posture. Bhiwapurkar et al [30][31] found interference with reading activities due to visual disturbance in backrest posture in fore-aft seat vibration for same vibration magnitude and frequency range. For the forward lean posture, the absence of this second peak implies that the motion of head is small -probably because of the low transmission of X-axis motion of the spine.…”

Section: Discussionmentioning

confidence: 99%

“…The study is conducted on the vibration simulator developed as a mockup of a railway vehicle, housed in partially soundproof room. 30,31 It consists of a platform of 2 m Â 2 m size, fabricated from a light aluminum alloy frame with thick steel plates at the top and bottom to which the three exciters pushrods are bolted via ball joints. The platform incorporates a table and chairs with rigid wooden seats securely fixed.…”

Section: Subjects and Subject Posturesmentioning

confidence: 99%

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Effects of posture and vibration magnitude on seat to head transmissibility during exposure to fore-and-aft vibration

Bhiwapurkar¹,

Saran

Harsha

2018

Journal of Low Frequency Noise, Vibration and Active Control

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An experimental study has been conducted on the vibration simulator, developed as a mockup of a railway vehicle. In this paper, the effect of variations in the posture and vibration magnitude on head motions in three translational directions (fore-and-aft, lateral and vertical) are studied with seat vibration in fore-and-aft direction. Thirty healthy male subjects are exposed to random vibration with three vibration magnitudes of 0.4, 0.8 and 1.2 m/s 2 r.m.s. over the frequency range 1-20 Hz. The data results are analyzed in terms of seat-to-head transmissibility (STHT) in two sitting postures; backrest and forward lean. Vibration measurements of the head motions are made with an apparatus (bite-bar). The study confirms that the measured responses to single fore-and-aft axis vibration have shown notable cross-axis responses. An increase in the excitation magnitude consistently revealed a decrease in the response peak magnitude and the corresponding resonant frequency, particularly in the presence of a back support. Such non-linear behavior has been interpreted as a non-linear softening effect in the muscle tension under increasing intensity of vibration. The use of a back support significantly alters the biodynamic responses of the seated body, which is attributable to the constraint due to the backrest support.

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Section: Discussionmentioning

confidence: 99%

Section: Subjects and Subject Posturesmentioning

confidence: 99%

Effects of posture and vibration magnitude on seat to head transmissibility during exposure to fore-and-aft vibration

Bhiwapurkar¹,

Saran

Harsha

2018

Journal of Low Frequency Noise, Vibration and Active Control

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“…The vibration magnitudes and postures that are relevant for train passengers performing sedentary activities are chosen. 18 This experimental study is useful in vehicle seat design and biodynamic study of the human body under low-frequency vibration. It was hypothesized that the resonance peak and the resonance frequency of the transmissibility would decrease with increases in vibration magnitude, but that the extent of the decrease would vary with posture.…”

Section: Introductionmentioning

confidence: 99%

Seat to Head Transmissibility during Exposure to Vertical Seat Vibration: Effects of Posture and Vibration Magnitude

Bhiwapurkar¹,

Saran²,

Harsha³

2019

The International Journal of Acoustics and Vibration

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The low frequency vibration transmitted to the body can affect the comfort, performance, and health of humans. In this paper, the effect of variations in posture and vibration magnitude on the head motion in three translational axes (fore-and-aft, lateral and vertical) has been studied with a vertical seat vibration. Thirty healthy male subjects were exposed to random vibration with three vibration magnitudes of 0.4, 0.8, and 1.2 m/s2 rms over the frequency range of 1–20 Hz. The results are analysed in terms of seat-to-head-transmissibility (STHT) for the head motions in two seated postures (backrest and leaning forward on table). The measurement of the head motion was made with an apparatus (bite-bar) specifically developed for this purpose. The measured responses to a single axis seat vibration have also shown notable cross-axis responses in both vertical and fore-and-aft axes for both postures. The crossaxis fore-aft and vertical STHT responses showed single peak near 5 Hz in both postures. An increasing intensity of vibration yields a non-linear softening effect in the muscle tension, particularly in the presence of back support, however, the body stiffens under a greater upper body motion in the forward leaning posture. The combined effect of the unsupported back and hands support was observed to be more pronounced around the resonance peak in the forward lean posture.

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“…Also, most passengers reported reading discomfort due to the train vibrations in response to a questionnaire used in these studies. Bhiwapurkar, et al, 3,4 conducted the laboratory experiment on reading of a word chain in English, a Hindi newspaper, and an English e-paper under vibration exposure by measuring subjective and objective responses. The results revealed a strong influence of the WBV on the performance reduction in reading performance and increase in perceived difficulty.…”

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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Objective and subjective responses of seated subjects while reading Hindi newspaper under multi axis whole-body vibration

Cited by 17 publications

References 11 publications

Effects of posture and vibration magnitude on seat to head transmissibility during exposure to fore-and-aft vibration

Effects of posture and vibration magnitude on seat to head transmissibility during exposure to fore-and-aft vibration

Seat to Head Transmissibility during Exposure to Vertical Seat Vibration: Effects of Posture and Vibration Magnitude

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

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