Discomfort during lateral acceleration: Influence of seat cushion and backrest

Abstract

Lateral acceleration causes discomfort but how the discomfort depends on the frequency of acceleration or characteristics of seating is poorly understood. Using magnitude estimation, twelve male subjects rated the discomfort caused by lateral oscillation at eight frequencies (0.2 to 1.0 Hz) across four seating conditions (a rigid seat and a train seat, both with and without backrests). Discomfort increased with increasing frequency of lateral acceleration in a similar manner for all four seating conditions. However, at all frequencies and with both seats there was less discomfort when sitting with backrest support than without. Least discomfort occurred on the train seat with backrest and greatest discomfort on the rigid seat without backrest. Current standards predict an additive effect of backrest on vibration discomfort, but the findings show that low frequency lateral acceleration can cause less discomfort when sitting with a backrest than when sitting on the same seat without a backrest.

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

“…The published computational models are consistent with data collected in humans showing that the resonant frequency of the human body is between 5–10 Hz (Zeeman et al 2015; Matsumoto,Griffin 2002; Qiu,Griffin 2010; Basri,Griffin 2011), and that the resonant frequency of the human hand-arm system is between 100–300 Hz depending on the location of the measurement (Dong, Welcome, et al 2004; Dong, Welcome,Wu 2005; Dong et al 2006; Wu et al 2007; Wu et al 2008). These models, along with experimental data collected in human and animal subjects have helped predict how various interventions may reduce the transmission of vibration from a vehicle or tool to the body (Krajnak et al 2015; Hewitt et al 2015; Md Rezali,Griffin 2016; Welcome et al 2016; Md Rezali,Griffin 2017; Basri,Griffin 2014; Qiu,Griffin 2012; Jonsson et al 2015; Beard,Griffin 2013; Ji, Eger,Dickey 2017; Du et al 2018; Johnson et al 2018).…”

“…Because many patients seen for back pain do not have injuries to their spine or disks, which are can be detected using imaging methods, understanding the contribution of soft tissue injury (i.e., skeletal muscle, tendons, ligaments) to the incidence of back pain is critical for identifying interventions that will prevent injuries (Du et al 2018; Bovenzi et al 2015; Bovenzi 2010; Palmer et al 2003; Bovenzi 1996; Bovenzi,Zadini 1992). Data collected in humans, have been used to alter seat design to reduce vibration transmission and improve comfort in vehicles (Qiu,Griffin 2012; Beard,Griffin 2013; Basri,Griffin 2014; Jonsson et al 2015; Ji, Eger,Dickey 2017; Du et al 2018; Johnson et al 2018). Mental fatigue and stress can also exacerbate pain, therefore, taking breaks to stretch and help maintain mental alertness may also improve pain perception (Yung et al 2017; Tachi et al 2004).…”

Parsimonious shooting heuristic for trajectory design of connected automated traffic part II: Computational issues and optimization

“…Highway trac is frequently forced to decelerate and accelerate (or stop and go), particularly along signalized arterials due to alternating green and red lights. Vehicles engaged in repeated stop-and-go movements are exposed to high crash risks (Homann and Mortimer, 1994), extra driver discomfort (Beard and Grin, 2013), and excessive fuel consumption and emissions (Li et al, 2014). Further, when vehicles slow down or stop, trac throughput decreases and capacity drops (Cassidy and Bertini, 1999), causing excessive travel delay.…”

The Evaluation of Seat-Comfort, Body Discomfort and Seat Vibration Performance in a Dynamic Testing Environment

“…Automobile seats provide important safety functions including restraining drivers and passengers, supporting body postures and vehicle vibration mitigation (Ebe & Griffin, 2000, 2001. Seat comfort is an important aspect and has extensively been studied in vehicle seat design (Beard & Griffin, 2013, 2014Ebe & Griffin, 2001). Previous studies have shown that foam properties including stiffness and thickness, can have a major influence on occupants' comfort, discomfort, and vibration isolation performance (Joshi, Bajaj, & Davies, 2010;Mansfield, Sammonds, & Nguyen, 2015;Mehta & Tewari, 2002;Patten, Sha, & Mo, 1998;Zhang, Qiu, & Griffin, 2015).…”