Cab RLDA Using VI & MI Approach: A Co-Simulation of ADAMS/Acar & FEMFAT Lab VI/MI

Abstract

<div class="section abstract"><div class="htmlview paragraph">The current approach of hybrid RLDA is typically incapable of providing accurate dynamic loads coming on cab at chassis-to-cab load transfer locations, primarily due to the following two reasons. Firstly, all of the model parameters of the vehicle, which is put on the 4-post, are not known. Secondly, MBS (Multi-body System) Cab model is multi degree of freedom with rigid bodies, flex bodies, contacts and non-linear force elements. Therefore, if the system identification is to be performed manually it becomes an arduous and humanly impossible task.</div><div class="htmlview paragraph">Towards generating accurate dynamic loads on cab, an approach using FEMFAT LAB - VI & MI has been developed which involves a two-step process: a) Generating MBS excitation by back calculating from measured frame response – VI (Virtual iterations). b) Fine tuning modelling parameters to match measured cab response – MI (Model Improvement). To execute the VI & MI approach for calculating dynamic loads on cab through 4-poster & 7-poster simulation, measured road data (load, acceleration, displacement etc.) is required. Road data has been acquired on a Tata vehicle at strategically identified locations on various test tracks in two different loading conditions. The flexible MBS model had been created in MSC-ADAMS/Acar for 4-poster & 7-poster simulations. MBS excitation signal is back calculated from measured frame response through VI approach in FEMFAT Lab-VI tool and improvement in accuracy is demonstrated through correlation between simulated v/s measured cab & frame responses, in terms of relative damage. Furthermore, Model Improvement (MI) is done by updating relevant parameters identified by a diagnose tool to improve the correlation level. Finally, the improvement in accuracy of simulated outputs using VI & MI approach over existing process is also demonstrated.</div></div>