Evaluation of Two Wheeled Vehicle Frame through Virtual Simulation and Testing

The main challenge that arises in the design of a motorcycle frame is its effect on the functionality on the vehicle, its effect on ride comfort and its durability. While functionality and ride comfort due to frame can be evaluated by subjectively testing it before the product reaches customer, evaluation of its durability is a complex process. This work is an investigation of the frame body of a 100 cc vehicle in India. These vehicles are subjected to endurance tests on a rough road at vehicle level to quantitatively evaluate their frame durability. However, such tests require significant time and cost, so an attempt has been made to develop a virtual rough road simulator to extract forces involved in it and testing the frame at component level with those loads on a test rig. Also durability results were compared and analyzed with the track data and frame test rig. This paper presents an approach for efficiently evaluating motorcycle frame body durability using external loads predicted from measured strain data from test track and identifying an equivalent repeated load cycle which will simulate the load histories obtained from the track. These loads were calculated by simple fatigue factor and can be used as boundary conditions of static analysis. The advantage of this method is that it allows relatively precise reproduction of actual boundary conditions without the data usually needed for dynamic simulation such as tire and suspension characteristics which often take large amount of time and man-hour to obtain. Although this approach is simple, there are a lot of factors to be considered for gaining useful results in a broad range of stages in the motorcycle frame body development process.