New Equivalent Static Load (ESL) Creation Procedure for Complete Vehicle 2024-01-2944

By analyzing the dynamic distortion in all body closure openings in a complete vehicle, a better understanding of the body characteristics can be achieved compared to traditional static load cases such as static torsional body stiffness. This is particularly relevant for non-traditional vehicle layouts and electric vehicle architectures. The body response is measured with the so-called Multi Stethoscope (MSS) when driving a vehicle on a rough pavé road (cobble stone). The MSS is measuring the distortion in each opening in two diagonals. During the virtual development, the distortion is described by the relative displacement in diagonal direction in time domain using a modal transient analysis. The results are shown as Opening Distortion Fingerprint ODF and used as assessment criteria within Solidity and Perceived Quality. By applying the Principal Component Analysis (PCA) on the time history of the distortion, a Dominant Distortion Pattern (DDP) can be identified. The DDP means that more than 50 % of the body deformation states for a given pavé time history are similar to each other. This paper presents a deeper analysis of the forces which are associated to this Dominant Distortion Pattern (DDP). The new aspect of this analysis is that all forces (54 in total) between the wheel suspension and the trimmed body are considered. Based on the results of this force analysis, a new procedure for creating an Equivalent Static Load (ESL) was developed. Finally, by automating this creation procedure it is shown how the new ESL can be integrated in the virtual vehicle development.