Discomfort, Pressure Distribution and Safety in Operator’s Seat – A Critical Review H.S.Dhingra

Overall seating comfort is influenced by both static and dynamic characteristics of seat system. Therefore, the present study is an overview of work related to comfort in seat-operator interface affected by static and dynamic pressure distribution, and other related parameters involved in seat comfort, low back pain, seat design and safety in seats. A critical review has been presented on the subject, with a purpose to provide quick reference for the future researchers . The studies revealed that seat-human interface pressure on the soft seat is more evenly distributed on a larger effective contact area than on a rigid seat. The pressure distribution at human seat interface of a rigid seat is affected by seat height, posture, type of cushion and frequency and vibration. The dynamic pressure at interface is nearly sinusoidal in the vibration range of 1-10 Hz. Under vibration excitation, increase in excitation magnitude causes increased maximum ischium pressure and maximum effective contact area around resonant frequency of 4.5 to 5.0 Hz. Postural stress, whole body vibration and shocks are recognised as important factors, causing low back pain. This however, can be reduced by provision of lumbar support, side support and suitable cushion type.