Vibration Attenuating Characteristics of Air Filled Seat Cushions

Huston, Dryver R.; Johnson, Christopher C.; Wood, Marie; Zhao, Xiangdong

doi:10.1006/jsvi.1998.2016

Cited by 14 publications

(10 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This research is consistent with previous laboratory results which demonstrate negative relationships between body mass, transmission coefficient and seat effective amplitude transmissibility [19,20,22] as well as the positive relationships seen between body mass and vibration measures of total absorbed power, mechanical impedance and apparent mass [21][22][23][24][25][26]. These laboratory results thus support a negative relationship between body mass and vibration exposure.…”

Section: Discussionsupporting

confidence: 91%

“…Although high levels of WBV have been associated with occupational LBP, body mass may be an important intrinsic factor which modulates this relationship in different ways. Several laboratory studies ( Table 1) have investigated the influence of body mass on various WBV exposure measures (including mechanical impedance, absorbed power, vibration transmission and apparent mass) under varying experimental conditions including; seat cushion, seat suspension, back rest, seat and tyre pressure, vibration magnitude and frequency [19][20][21][22][23][24][25][26] Extrapolation from these laboratory studies generally demonstrates negative associations between increased body mass and vibration exposure.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Influence of Body Mass on Whole-Body Vibration: A Quad-Bike Field Study

Mani¹

2011

TOERGJ

View full text Add to dashboard Cite

Objectives: The aim of this field study was to explore the relationship between body mass and quad bike induced whole-body vibration (WBV) exposure in a group of New Zealand rural workers. Methods: WBV exposure was recorded using a seat pad mounted tri-axial accelerometer while rural workers (n=34) were driving a quad bike for approximately half an hour on a pre-marked track on farm terrain. Personal factors such as age, height and quad bike driving experience were also surveyed and included as co-variates. Vibration dose value (VDV) was calculated by analyzing the recorded raw vibration data samples (n=34) using vibration analysis software and corrected to a one hour equivalent exposure for further statistical analysis. To evaluate for the relationship between variables of interest (body mass, height, age and driving experience) and one hour VDV Z (1hrVDV Z), univariate and multivariate linear regression analysis were conducted. Results: Mean 1hrVDV Z was 13.2 m/s 1.75 exceeded the VDV exposure action value of 9.1 m/s 1.75. Univariate analysis demonstrated body mass (R 2 = 0.340) significantly (p < 0.0003) associated with 1hrVDV Z while age, body height and quad bike driving experience were not. In a multivariate backward linear analysis body mass, height, and experience combined to explain 38% (R 2 = 0.376) of the variance in 1hr VDV Z, however, only body mass (p= 0.0004) demonstrated statistical significance. Conclusion: Body mass is significantly and negatively associated with quad bike induced WBV (1hrVDV Z) in a group of New Zealand rural workers.

show abstract

Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

The Influence of Body Mass on Whole-Body Vibration: A Quad-Bike Field Study

Mani¹

2011

TOERGJ

View full text Add to dashboard Cite

show abstract

“…According to Gellerstedt (2002), 4,000 control inputs per hour have to be carried out by the operator, due to the lack of automatic functions of the boom and harvester head. Despite the ergonomic design of the cabs, the operators of mobile machinery are exposed mainly to noise (Hansson 1990;Axelsson 1998;Marsili et al 1998;Nieuwenhuis, Lyons 2002;Messingerová et al 2005;Sümer 2006;Beuk et al 2007;Gerasimov, Sokolov 2009;Aybek et al 2010;Bilski 2013), whole-body vibrations (Boileau, Rakheja 1990;Burdorf, Swuste 1993;Magnusson et al 1993;Hansson 1995;Huston et al 1999;Hinz et al 2002;Paddan, Griffin 2002;Hostens, Ramon 2003;Chen et al 2003;Sherwin et al 2004a,b;Deprez et al 2005;Kolich et al 2005;Tiemessen et al 2007;Li et al 2008;Gerasimov, Sokolov 2009), microclimatic conditions -mostly temperature, and airflow velocity inside the cab (Gao, Niu 2004;Kaynakli, Kilic 2005;Huang et al 2006;Mezrhab, Bouzidi 2006;Cengiz, Babalik 2007;Farzaneh, Tootoonchi 2008;Kim et al 2009;Zhang et al 2009a,b;Alahmer et al 2011), and severe mental and sensory load (Axelsson, Pontén 1990;Poschen 1993;…”

mentioning

confidence: 99%

Objective and subjective assessment of selected factors of the work environment of forest harvesters and forwarders

Martin¹,

Messingerová²,

Ferenčík³

et al. 2016

J. For. Sci.

View full text Add to dashboard Cite

This article was aimed at assessment of selected factors of the work environment, which influenced the operators of harvesters and forwarders. The selection of the work environment factors was based on a thorough literature survey. From the survey exposure to whole-body vibrations, noise (equivalent and peak), microclimatic conditions and mental load were selected for detailed observations. The measurements were conducted according to international standards and assessed according to European or national legislation. Subjective assessment of the effects of the work environment was conducted through a structured interview. The exposure to whole-body vibrations was 0.5 m·s -2 . The equivalent noise exposure was 78 dB, peak noise exposure was 130 dB. The average temperature inside the machine cabs was 17.9°C and average airflow velocity was 0.06 m·s -2 . Mental load was high according to the Meister questionnaire, three operators considered the load inadequate, two considered it adequate. Subjective assessment showed that operators considered other factors to be light or no load.Keywords: noise exposure; whole-body vibrations; microclimate; mental load Work environment is a set of all conditions in which workers carry out their work. It consists of all workers and factors present at the workplace, or of those who have to do with the work and influence the health or comfort of workers. The worker is exposed to many harmful factors which interact and their joint effect can be synergistic or complementary (Schwartz et al. 2013).Operators of multi-operational machinery carry out their tasks in ergonomically designed cabs capable of partial attenuation of noise and vibrations caused by the machine movement, driving gear, and working parts of the machine. Cabs are also equipped with air conditioning and glare reducing windows. Some factors (e.g. electromagnetic, ionising radiation, various chemical factors, or energy expenditure) do not apply to the jobs of multioperational machinery operators. Their assessment would only consume time with no significant effect on the overall outcome of the assessment. The nature of work in mechanized logging partially shifted from physical to mental after employment of multi-operational machinery. The need for muscular activity decreased and the need to stay concentrated and alert through long periods grew in importance. Harvester operators have to be able to process a lot of information, react quickly, and retain their concentration in monotonous, repetitive operations (Axelsson, Pontén 1990;Poschen 1993;Gellerstedt 1997;Gellestedt et al. 1999;Tsioras 2012). Operating the machines is quite demanding. According to Gellerstedt (2002), 4,000 control inputs per hour have to be carried out by the operator, due to the lack of automatic functions of the boom and harvester head. Despite the ergonomic design of the cabs, the operators of mobile machinery are exposed mainly to noise (Hans-

show abstract

“…However, these two methods could not present realistic human geometry. Other researchers experimentally determined if seat cushions of a selected wheelchair could minimize the transmission of vibrations to users [16,23,24]. The main goal of our study was to investigate the effects of vertical vibration on subcutaneous stress of buttocks sitting on three different seat cushions by using a finite element modeling approach.…”

Section: Introductionmentioning

confidence: 99%

Finite Element Analysis of Contact Pressures between Seat Cushion and Human Buttock-Thigh Tissue

Tang¹

2010

Engineering

View full text Add to dashboard Cite

Unrelieved pressure on load-bearing muscle tissues of humans can produce pressure ulcers. In a seated upright posture, the highest pressures occur inferior to the ischial tuberosities (ITs). Moreover, the vibration can initiate the development of pressure ulcer. Therefore, the seat cushion is not only used to lower the maximum seating pressure on buttocks but also minimize the transmission of vibration to human body. The purpose of this study was to investigate the effects of varying vertical vibration frequencies on seat-interface contact pressure during sitting on three different seat cushions by using a finite element modeling approach. A simplified two-dimensional human buttock-thigh model was developed to simulate the mechanical response of the muscle of buttocks and thigh under vertical vibration. Static and vibrational loads with five different frequencies of 0.1, 1, 10, 30 and 50 Hz and the same amplitude of 3 mm were applied to different seat cushions. The result showed that the "SAF 6060" seat cushion with both hyperelastic and viscoelastic behaviors could be effective in reducing the amplitude of varying maximum contact pressure, especially for the frequency of 10-20 Hz. This method could help in design of seat cushions with appropriate material properties and shape so as to reduce vibrations transmitted to human body at a certain frequency range.

show abstract

Vibration Attenuating Characteristics of Air Filled Seat Cushions

Cited by 14 publications

References 1 publication

The Influence of Body Mass on Whole-Body Vibration: A Quad-Bike Field Study

The Influence of Body Mass on Whole-Body Vibration: A Quad-Bike Field Study

Objective and subjective assessment of selected factors of the work environment of forest harvesters and forwarders

Finite Element Analysis of Contact Pressures between Seat Cushion and Human Buttock-Thigh Tissue

Contact Info

Product

Resources

About