Abstract
Component level modal behavior prediction is an important task of any overall system dynamics study. The objective of the current work is to predictthe contribution of structural vibration of ‘swing arm’ of a motorcycle to its overall vibration and harshness behavior. This objective is met by determining the force transfer characteristics and modal behavior of the swing arm. This involves determination of structural frequency response function measurement in the laboratory which forms the pre-requisite set of data for modal prediction and further can be used to correlate with theoperational response measurements on the road. However this paper does not include road measurements but the laboratory experiment that are required. A conventional motorcycle model of Pulsar 150cc bike’s swing arm is chosen the for this research work. Output response of the swing arm is obtained strategically, mounting accelerometers on the component ’swing arm’ andexciting it at the location corresponds to the connection points with the frame. The excitation given is an impulse and hence, the corresponding frequency response functions (FRFs) were obtained to describe the structural force transfer characteristics. TheseFRFs are further processed to get modal frequencies and the mode shapes which are then compared with the numerical findings. And the numerical model is fine-tuned to match closely with experimental results. This FE model can further be used to study the influence of design and material over the modal behavior without having physical component to be manufactured.
Keywords: Frequency Response Function, vibration, swing arm, experimental modal analysis