Evaluation of Whole-Body Vibration (WBV) of Dozer Operators Based on Job Cycle

Abstract

Dozer operators are frequently exposed to high levels of occupational vibration. So far, no study reported component wise evaluation of dozer cycle of operation. In the present study, WBV data were collected by placing the trial accelerometer at operator’s seat-surface and at seat-back. Frequency-weighted root mean square (RMS), vibration dose value (VDV) and crest factor were collected for each dozer for two phases’ forward motion and return motion. All the dozers under study were found to be in severe zone with respect to measured RMS, during forward motion and return motion, irrespective of type of measurements (i.e., seat-surface and seat-back). As per VDV, out of eight dozers three dozers were found to be in caution zone during forward motion and three in return motion. According to EU Directive 2002 (as per RMS), all the dozers under study have reported exposure action value above 0.5 m/s². Further, out of eight dozers, four dozers have shown exposure limit value above 1.15 m/s² for seat-surface measurements and three dozers for seat-back measurements. Vibration mitigation strategies should be adapted not just based on intensity of vibration but also with respect to dominant axis of vibration. Considering the severe health risk due to the translational vibration (i.e., in x-direction), the vibration risk in the forward x-direction can be reduced by using seat belt; similarly in rear x-direction it can be attenuated by placing lumber-assisted back rest.