Numerical Prediction of In-Plane Vertical Dynamics(IPVD) Performance on a Quarter Car at the Pre-CAD Preliminary Stages of Product Development

In the present time, almost every motor vehicle company plans to launch a new vehicle or two on a per annum basis. With the time crunch and cost reduction in mind the R&D(Research and Development) process for every vehicle needs to be wrapped up in a hurry. Due to this, testing time for every vehicle is shortened drastically. Yet, to have safe, sound vehicle in the market, to maintain the company's rapport in the market and among the competition, the testing of new product in comparison with the benchmark vehicle is given its due importance always. Traditional vehicle performance takes use of a series of physical prototype evaluations by skilled drivers, who analyze the vehicle performance in subjective and objective terms either in lab or in road in comparison with benchmark. The problem with this approach is the fact that it is completely dependent upon physical component prototypes, whose costs and construction lead times cannot be afforded in the current tight development cycles. All these lead to innovative and research oriented development in the virtual testing environment.

This paper presents an approach based on ranking score derived from simulation tools technical data that has been successfully applied at Tata Consultancy Services Ltd, which not only defines optimized solution for the achieving the target but also to evaluate the benchmark performance which aids in preliminary stages of new product development. This work focuses on the methodology development on estimation of In-Plane Vertical Dynamics(IPVD) performance characteristics on a quarter car model through numerical simulation which is very much necessary for predicting the ride comfort and road holding capabilities. A 2 D.O.F(degrees of freedom) model that represents a quarter car was used for this purpose. The model is constructed with parameterization, customized for this application in order to reduce the time required to build different configuration models and to get the optimum design choice for IPVD performance. The model that has been built has 2 D.O.F and excited with road displacements either in terms of frequency inputs or actual road profiles. Detailed procedure for evaluating the ride comfort, road holding, and its quantifying metrics has been explained and relatively compared with benchmark vehicle having different vehicle configuration.

The use of this numerical technique and ranking scores to evaluate the IPVD characteristics addressed challenges due to the non-availability of benchmark test data in the initial phase of new vehicle development where the rational decisions are taken and most of project cost has been decided.