an investigation of seat vibration in universal 650m tractor

whole body vibration can deteriorate health bringing about or back pain or spinal column injury, resulted from continuing exposure to vibration. also exposure to vibration can cause disorder in central nervous system and adversely influence vascular and skeletal systems. in this research, the vibration of universal 650m tractor seat and its effect on the operator in five levels of engine speeds: 1000, 1200, 1400, 1600 and 1800rpm, in a vertical direction and while driving on asphalt road was evaluated. also rms(root mean square) of acceleration and vdv(vibration dose value) were measured. the experiments showed that the dominant frequency of vibration in all speeds on the seat, were related to revolutions of the engine and piston stroke. seat vibration frequency was increased with increase in the number of motor speed. rms of acceleration in speeds from 1000 to 1800rpm were 1.93, 2.26, 2.4, 2.5 and 3.65 , respectively. the vdv values in speeds from 1000 to 1800rpm were 2.34, 2.49, 2.74, 3.1 and 4.29 , respectively which showed that were proportional to the engine speed. the results indicated that allowable time to achieve standard values of 15 (iso 2631) in speeds 1000, 1200, 1400, 1600 and 1800rpm, were 20.8, 11.1, 7.47, 4.72 and 2.1 hours indicating that exposure time, in high speeds, must be reduced