Session: 08-01-01: General Dynamics, Vibration, and Control I

Paper Number: 165535

Sensitivity of Ride Comfort of a Motorcycle to Rear Mounting System 

Although the use of an engine mounting system (also called as the vibration isolation system) is limited to very few motorcycle manufacturers, its use is inherently associated with ride comfort and planar handling [1, 2]. A typical engine mounting system consists of three to four engine mounts that are used to assemble the powertrain to the frame with each mount designed to be in compression or shear [3]. In a typical motorcycle layout, the swingarm couples the dynamics of the rear unsprung mass with the sprung mass through the engine mounting system. As a result, the engine mounting system may have an influence on the planar handling of the motorcycle while directly influencing ride comfort. This study uses an existing planar model from the literature [3] to investigate the sensitivity of ride comfort to the stiffness, damping, and location of the rear mounts. All other parameters are adopted from similar studies in the literature [1,2,3]. The model has eight degrees-of-freedom and is capable of capturing the hop of the two unsprung masses as well as bounce and pitch motion of the sprung mass, and the sprung mass is connected to the powertrain through the engine mounting system. The rider is assumed to be in an upright position without any consideration to different riding postures and any influence that these postures may have on ride comfort. Different levels of the three parameters are used to investigate the influence on ride comfort and handling. The model uses the road surface irregularity as the primary source of excitation input while the motorcycle is traveling in a straight line at a constant velocity. Three distinct road surfaces with different conditions have been used from the literature for analysis [4], and acceleration spectrum of the sprung mass is used as the primary gage of ride comfort. Results indicate that the rear mounting system is influential in the determination of ride comfort at specific locations of the motorcycle while also affecting planar handling.

[1] Cossalter, V., 2006, Motorcycle Dynamics, Second Edition, Lulu, Morrisville, NC, USA.

[2] Cossalter, V., Doria, A., Garbin, S., Lot, R., 2006, Frequency-domain method for evaluating the ride comfort of a motorcycle, Vehicle System Dynamics, 44, pp. 339–355.

[3] Kaul, S., 2020, Planar Dynamics of a Motorcycle: Influence of Vibration Isolation System Nonlinearity, International Journal of Acoustics and Vibration, 25, pp. 597–608.

[4] Sun, L., 2001, On human perception and evaluation to road surfaces, Journal of Sound and Vibration, 247, pp. 547–560.

Presenting Author: Brennan Long Milwaukee School of Engineering

Presenting Author Biography: Graduate Student,
Milwaukee School of Engineering

Authors:

Brennan Long Milwaukee School of Engineering
Sudhir Kaul Milwaukee School of Engineering