Vibration analysis of motorcycle handlebar for riding comfort using tuned mass damper

Vehicle comfort is related to vibrations induced due to surface irregularities and power generation and transmission parts. Long exposure to high vibrations may lead to numbness, stiffness, and pain in the rider's hand parts such as fingers, shoulders, and neck. It is a challenge to design a good suspension system and vibration absorber which isolates the driver/rider from the induced vibrations. The principle aim of a vehicle's suspension system/vibration absorber is to isolate the occupant from the induced disturbances, while still allowing the average driver to maintain control over the vehicle and drive it safely. The purpose of the present study is to investigate the vibrations in the motorcycle handlebar and modify the handlebar to reduce the vibration for good ride comfort without affecting its handling. A motorcycle with an under square engine is selected for the experimentation. The under square engine has more stroke length than bore diameter and hence it is more susceptible to generate vibrations. A tuned mass damper system is designed and developed to attenuate handlebar vibrations. To investigate and predict vibration attenuation levels in handlebar at different operating conditions, a proper design of experiments (DOE) is carried. In the DOE, the effects of factors such as motorcycle engine speed, mass on handlebar have been studied on vibrations at the handlebar. The objective of DOE is to develop a robust model that predicts the handlebar vibrations of a motorcycle which is highly desirable when rider exposes to vibration for a long period. The results of the investigation show vibration attenuation from 23 to 66 % at various engine speeds. The effect of the tuned mass damper is substantially visible at higher engine RPM hence proper modification of handlebar becomes essential in case of high revving applications where riders are exposed to high vibrations for longer periods.