TRANSMISSION OF YAW SEAT VIBRATION TO THE HEAD

✍ Scribed by G.S. PADDAN; M.J. GRIFFIN

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 253 KB
• Volume: 229
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1006/jsvi.1999.2598

✦ Synopsis

The transmission of yaw-axis vibration to the heads of seated subjects has been investigated at frequencies below 5 Hz. The variability between and within subjects and the e!ects of backrest contact, visual environment and the position of the centre of rotation have been investigated. The subjects sat on a rigid #at seat and were exposed to random motion at a magnitude of 1)0 rad/s r.m.s. (root-meansquare) for 2 min. Head motion was measured in six axes using a light-weight bite-bar held between the teeth. Twelve male subjects participated in a study of the e!ect of backrest contact and visual conditions and one male subject participated in a repeatability study. A &&back-on'' posture (subject's back in contact with the seat backrest) increased the frequency of maximum transmissibility from 2 to 3 Hz compared with a &&back-o!'' posture. There was little change in transmissibility with the subjects sitting with their eyes open compared to their eyes closed. With increasing separations between a subject and the centre of rotation (at six distances from 0 to 500 mm with the subject facing outwards) there were large increases in lateral acceleration at the head.