No abstract

Today the automotive market is ever more competitive and vehicles must satisfy the requirements of the customers in all respects: handling, comfort, acoustics, fuel economy, etc. Therefore OEMs have to launch innovative products in a short development timeline: the time to market (TTM) of new vehicles has continually decreased and nowadays the developing process of a new car is completed in less years than in the past. This scenario emphasizes the role of CAE in the vehicle design engineering design and the necessity of exploiting its potentialities, in order to shorten the TTM and to reduce the impact of experimental tests on it. In this context a step-by-step approach with multi-physics 1D environment such as LMS Imagine. Lab AMESim is proposed in order to monitor vehicle performances in all the design stages, thanks to the employment of models with increasing complexity. In addition the ultimate step can be employed for performing a multi attribute optimization on vehicle performance metrics in order to find the best attributes balancing and to pass the preliminary recommendations to the design with a considerable time-saving respect to 3D MBS models. This paper briefly describes the process for building 1D models with LMS Imagine.Lab AMESim and moreover it shows the definition of a multi attribute optimization algorithm in terms of handling performances with the most complex model.

Body reinforcements may have large influence in the handling perception of a professional driver. This paper presents testing and CAE techniques to approach and analyze the phenomena. A full vehicle multi body model correlated against test data was built. The model includes all vehicle subsystems: front and rear suspensions with rotating wheels and tire model in Magic Formula representation, steering line, powertrain mounting system and car body. Flexible components have been implemented for the car trimmed body, the front subframe and the rear twist beam suspension. A special vehicle set-up has been defined for the testing session, including the standard handling equipment and an advanced system measurement based on strain gauges located on the vehicle body. Strain gauge locations have been defined through support of the simulation. Several handling maneuvers (constant radius cornering, step steering at different lateral accelerations, ISO lane change and reverse ISO lane change) have been performed. Results from strain gauges have been obtained and analyzed. Advanced testing equipments are necessary to demonstrate the influence of body flexibility, which standard handling testing equipment does not allow. This represents the first step for understanding the advanced handling perception feeling due to the body deformation and for defining a systematical approach to correlate with objective measurements.