Fore-and-aft transmissibility of backrests: Effect of backrest inclination, seat-pan inclination, and measurement location

Jalil, Nawal Aswan Abdul; Griffin, Michael J.

doi:10.1016/j.jsv.2006.06.053

Cited by 14 publications

(14 citation statements)

References 8 publications

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“…The investigation further concluded that a single output -single input experimental model would be effective for measuring vertical vibration, though might not be effective for measuring the horizontal vibration. Transmissibility level for the car seated human changes with the adjustment of vertical position of human body and this fact was proved by the experiments on nonlinearity transmissibility of human body in vertical direction (Tufano and Griffin, 2012) and fore-aft transmissibility of car backrests (Jalil and Griffin, 2007).…”

Section: Vibration Measurement: Testing and Experimentsmentioning

confidence: 91%

Vibration in car seat- occupant system: Overview and proposal of a novel simulation method

Mondal¹,

Arunachalam²

2019

AIP Conference Proceedings

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In the modern automotive industries, vibration levels inside the human body and the car seat are mainly validated using the on-road vehicle testing or laboratory experiment. This paper aims to propose a novel bio-dynamic simulation technique which will provide the level of vibration in term of acceleration, displacement or velocity inside the car seated human body and the car seat itself. There are many existing simulation technologies in the market to provide vibration related solution for a specific portion or sub-portion of the human-car seat system, but this proposed novel simulation method will give a complete solution for the entire human body and car seat assembly inside an automotive structure under real life operating condition without conducting any real experiment and testing. Accomplishment of this project will take the existing technology to an advanced level to assess the dynamic interaction between the automotive seat and human mass and help to understand the effect of vibration in a more clear way by judging the three directional stiffness and damping values, mode shapes, random vibration, power spectrum, resonance frequencies and vibration transmission. This research will help to predict the final vibration data at different locations of the human and automotive seat, thus will try to fill up the gap in the latest technologies and omit the necessity of the expensive and robust experimental methods. A cutting edge technology will be achieved by this unique bio-dynamic simulation technique to understand the effect and estimation of level of vibration inside the car seat and its occupant.

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Section: Vibration Measurement: Testing and Experimentsmentioning

confidence: 91%

Vibration in car seat- occupant system: Overview and proposal of a novel simulation method

Mondal¹,

Arunachalam²

2019

AIP Conference Proceedings

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“…26 Reclining a seat increases the foreand-aft transmissibility of the backrest at resonance, probably because the inclination of the backrest and the seat pan cushion affect the biodynamic responses of the human body. 10 Changes in the seat track position also change how support for the mass of a human body is distributed between the seat pan, the backrest and the floor. The body weight has a strong association with the vertical apparent mass of the body at resonance but does not necessarily affect the vertical seat transmissibility of a seat pan cushion.…”

Section: Seat Transmissibility With Human Subjectsmentioning

confidence: 99%

Transmission of fore-and-aft vibration to the seat pan, the backrest and the headrest of a car seat

Zhang

Qiu

Griffin

2015

Proceedings of the Institution of Mechanical Engineers, Part D:

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Measurements of the transmission of vibration from the floor beneath a seat to interfaces between the seat and the human body are used to characterise the dynamic performance of the seat. Most studies of seat transmissibility concern the transmission of vertical vibration through seat pan cushions, but fore-and-aft vibration at a seat pan and backrest can also cause discomfort. This study investigated the transmission of fore-and-aft vibration through a car seat to surfaces on the seat pan cushion, the backrest cushion and the headrest, and also to the seat frame at these three locations. The study sought to understand the influences of the seat frame and the cushion foam and to provide data for dynamic modelling of the seat. The fore-and-aft transmissibility of the seat was measured with 12 human subjects and an SAE J826 manikin, using 120-s periods of fore-and-aft random vibration (0.25-40 Hz) at three magnitudes (0.4 m/s 2 r.m.s., 0.8 m/s 2 r.m.s. and 1.2 m/s 2 r.m.s.). With the manikin, there were three resonances (at 3.5 Hz, 12 Hz and 20 Hz) in the transmissibilities from the seat base to the seat pan frame and the seat pan cushion, and to the backrest frame and the backrest cushion. With the human subjects, the transmissibilities from the seat base to all six locations on the seat showed a principal resonance around 4 Hz. With increasing magnitude of the vibration, the principal resonance frequency in all the seat transmissibilities decreased. It is concluded that fore-and-aft resonances in the seat transmissibilities, especially to the backrest, are likely to affect vibration discomfort. There are large differences between the foreand-aft transmissibility of a seat with a manikin and those with human subjects, consistent with the human body having dynamics very different from those of a rigid mass. Non-linearities in the seat transmissibilities with the manikin and with the human subjects may be explained by non-linearity in the biodynamics of the body and the responses of the seat and the manikin.

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“…Many studies have been conducted in the field or the laboratory in which the effects of the adjusters on the vibration characteristics of the vehicle seat were investigated. 2,[19][20][21][22][23][24] Five different backrest inclinations (no backrest, and with a static backrest inclined at 0°, 30°, 60°and 90°) have been selected to determine the influence of the vibration discomfort induced by the backrest inclination. [19][20][21] The influences of the seat-pan and the backrest inclination on the fore-and-aft vibrations of two seats with respect to the transmissibilities were investigated by Abdul Jalil and Griffin.…”

Section: Introductionmentioning

confidence: 99%

“…2,[19][20][21][22][23][24] Five different backrest inclinations (no backrest, and with a static backrest inclined at 0°, 30°, 60°and 90°) have been selected to determine the influence of the vibration discomfort induced by the backrest inclination. [19][20][21] The influences of the seat-pan and the backrest inclination on the fore-and-aft vibrations of two seats with respect to the transmissibilities were investigated by Abdul Jalil and Griffin. 21 The first four orders of the modal characteristics of the vehicle seat in different slider positions were studied by Baik et al, 4 and the research showed that the position of the slider has an influence on each individual order of the modal frequency but does not affect the modal shapes.…”

Section: Introductionmentioning

confidence: 99%

“…[19][20][21] The influences of the seat-pan and the backrest inclination on the fore-and-aft vibrations of two seats with respect to the transmissibilities were investigated by Abdul Jalil and Griffin. 21 The first four orders of the modal characteristics of the vehicle seat in different slider positions were studied by Baik et al, 4 and the research showed that the position of the slider has an influence on each individual order of the modal frequency but does not affect the modal shapes. By measuring the variations in the positions of the three different adjusters (the height adjuster, the recliner and the slider) to evaluate the seat buzz, squeak and rattle characteristics, Seo et al 15 found the optimum position of the vehicle seat for modal experiments and used the position to perform experiments.…”

Section: Introductionmentioning

confidence: 99%

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Experimental study of the influence levels of different vehicle seat adjustments on the fore-and-aft modal characteristics using the orthogonal array method

Zhang

Li³

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part D:

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The vehicle seat modal characteristics (in particular, the first resonant frequency and the corresponding modal shape) play important roles in the seat design and the ride comfort. This paper investigated the relationship between the first modal characteristics and the positions of the adjusters on the vehicle seat. There are four adjusters on the vehicle seat to change its position so as to match the driver’s somatotype, the driving and the sitting habits. Different seat positions inevitably cause changes in the resonant frequency. An orthogonal array method was adopted to evaluate the influence levels of the adjusters by using a Pareto chart. It was found that the first modal (fore-and-aft) shape is almost uninfluenced by the variations in the adjuster positions, whereas the first modal frequency is greatly influenced by the changes in the adjuster positions. The first modal frequency is most affected by the variation in the slider position, followed by the variation in the headrest adjuster position, the variation in the recliner position and the variation in the height adjuster position.

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Fore-and-aft transmissibility of backrests: Effect of backrest inclination, seat-pan inclination, and measurement location

Cited by 14 publications

References 8 publications

Vibration in car seat- occupant system: Overview and proposal of a novel simulation method

Vibration in car seat- occupant system: Overview and proposal of a novel simulation method

Transmission of fore-and-aft vibration to the seat pan, the backrest and the headrest of a car seat

Experimental study of the influence levels of different vehicle seat adjustments on the fore-and-aft modal characteristics using the orthogonal array method

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