Experimental and numerical analysis of the roller-bench endurance test on a motorscooter

Abstract

This paper describes an activity aimed at analysing the loads occurring on a two-wheeler during one of the most widespread tests among two-wheeler companies. In this test, the vehicle with additional ballasts, is positioned on two rollers, having synchronized rotational speed, and is subjected to loads coming from obstacles positioned on the rollers' surface. In order to achieve an in-depth understanding of the loads produced by the test, a vehicle was provided with displacement transducers, accelerometers, and strain gauges. At the same time, two multi-body models of the test were set up, in which the motorscooter had a rigid frame or a flexible frame respectively. The dynamics of the tyre was reproduced by the rigid ring model, where the tyre interacts with the wheel rim by means of linear and rotational springs and dampers. The loads from the obstacles are evaluated on the basis of a series of experimental curves (envelope properties of the tyre) directly obtained with the tyres and obstacle employed for the tests. The comparison between experimental and numerical results regarding suspension strokes, wheel vertical accelerations, and vertical and longitudinal loads showed fairly good agreement; it is also shown how the model having the rigid frame overestimates the peaks in the vertical load. The availability of an accurate model for this kind of test in the early phase of the development process of new vehicles, allows the design of structural components to be optimized.