Vibration Transfer tests

The vibrations test performed on the shake table (Photo shown on right) is a procedure that is valid for testing in aircraft seating, large public transportation, heavy equipment seating, large 4x4 rigs, and RV’sand generally, transportation seats.

 
 

The improvement of the CBM Seat for large transport application is to provide an angular motion isolator. This reduces vibrations and stressful forces in the neck, chest, lumbar joints, pelvis, and legs by providing automatic seat angle tilting with instantaneous, self- angular adjustment of the seat cushion. For motion sickness concerns (0 to .5 Hz), tests indicate the CBM reduces vibration transfer by approximately 75%.

Repetitive stress of vibration transmission is reduced with lower magnitude forces acting on the body.

For health, comfort and perception issues ISO 2631-1 (Mechanical vibration and shock - Evaluation of human exposure to whole body vibration) is most concerned with z-axis values in the 4.4 - 9.5 Hz range where its frequency weighting factor, Wk is over 1.

Figure 9: Vibration transmission on z axis

Figure 9: Vibration transmission on z axis

As shown in Figure 9, the CBM Seat, as tested for a truck, reduces vibration transfer in the primary area of concern. This reduction is a significant benefit for extended driving periods, especially for full time drivers. ISO 2631-1 is also most concerned with values on the x and y axes in the 0.9-1.3 Hz range, where its frequency weighing factor, Wd is over 1. As shown in Figure 10, the CBM Seat noticeably reduces vibration transfer in the primary area of concern.

Figure 10: Vibration transmission on x, y axis.

Figure 10: Vibration transmission on x, y axis.

Overall, vibration tests confirm that the CBM Seat enhances performance by reducing the transmission of peak vibrations to the body. The most noticeable improvement appears on the z-axis. Also improved is the x-axis transfer (compression, z and shear loads, x, y).