The vibration discomfort of standing persons: evaluation of random and transient motions

Abstract

The discomfort of standing people experiencing steady-state vibration can be predicted from the root-mean-square of the frequency-weighted acceleration, but alternative methods are advocated for evaluating motions containing transients. Using the method of magnitude estimation, 20 standing subjects estimated the discomfort caused by octave-bandwidth random vibrations at two centre frequencies (1 and 8 Hz) in each of three directions (fore-and-aft, lateral, and vertical). For motions having seven different crest factors (i.e. the ratio of the peak to the r.m.s. value), the vibration magnitude required for similar discomfort, and a method predicting this equivalence, was determined.

Health effects associated with occupational exposure to hand-arm or whole body vibration

“…Other studies examining the effects of lower frequency vibration (10–60 Hz) have found that vibration at these lower frequencies is transmitted to the elbow, shoulder, wrist and neck (Bovenzi 2015, 2006; Bovenzi, Fiorito,Volpe 1987; Bovenzi, Petronio,DiMarino 1980; Bovenzi et al 2005). Exposures at these frequencies also result in faster fatigue of the muscles of the upper arm and shoulder (Tachi et al 2004; Stewart, Taneja,Medow 2007) and reports of increased discomfort (Wyllie,Griffin 2007; Thuong,Griffin 2011; Huang,Griffin 2014; Bovenzi,Hulshof 1999; Griffin,Bovenzi 2002; Zeeman et al 2015; House, Krajnak,Jiang 2016). This has lead researchers and other members of standards committees to suggest that the frequency weighting curve should be revised, and either different curves should be generated for different tools, or different curves should be generated for different portions of the hand-arm system (Bovenzi, Lindsell,Griffin 2000; Dong et al 2001; Griffin, Bovenzi,Nelson 2003; Organization 2005; Morioka,Griffin 2010).…”

Apparent mass distribution at the feet of standing subjects exposed to whole-body vibration

“…Literature studies (Hulshof and Veldhuijzen van Zanten 1987;Bovenzi and Hulshof 1999;Tiemessen, Hulshof, and Frings-Dresen 2007) showed that the continuous exposure to WBV may lead to musculoskeletal disorders, as well as physical and psychological fatigue. As a consequence, there are several aspects related to the WBV exposure of standing subjects that have recently been investigated, such as the identification of proper metrics for the evaluation of the discomfort (Moschioni, Saggin, and Tarabini 2010;Thuong and Griffin 2011), the effect of vibration on activity interference (Baker and Mansfield 2010) and the assessment of WBV exposure at the workplace (Thrailkill, Lowndes, and Hallbeck 2013). Experiments on the human body biodynamic response under WBV are commonly carried out in the standing, sitting and recumbent positions; the human body dynamic response is mostly analysed under two different perspectives: one describing the force -motion relations at the human -machine interface (mechanical impedance, apparent mass and absorbed power) and the other describing the vibration transmissibility through the body segments.…”

Response of the seated human body to whole-body vertical vibration: discomfort caused by mechanical shocks

“…However, experimental studies with whole-body vibration have found that the rate of growth of discomfort differs according to the frequency of vibration (e.g., Matsumoto and Griffin, 2005;Morioka and Griffin, 2006;Zhou and Griffin, 2014a), the direction of vibration (e.g., Griffin, 2007, 2009;Subashi et al, 2009), body posture (e.g., Thuong and Griffin, 2011;Griffin, 2012, 2013), and the characteristics of shocks (e.g., Ahn and Griffin, 2008).…”