Design assessment of a multiple passenger vehicle component using load transfer index ( $$ {\text{U}}^* $$ U ∗ ) method

In recent years, the study of the load transfer in the structure has achieved a growing attention from mechanical engineers, specifically in the vehicle industry. To further develop this relatively new branch of structural analysis and in particular the $$ {\text{U}}^* $$ index theory for load transfer analysis, it seems necessary to apply this method to different vehicle components. Therefore, in this study, one of the main load carrying components of a multiple passengers carrying vehicle was chosen for load transfer analysis. This choice has significant importance due to the focus of previous $$ {\text{U}}^* $$ index studies on small passenger vehicles, which have completely different structure and load paths. Another important feature of this study is the application of a sophisticated and detailed approach for choosing the loading and boundary condition. To address an actual working condition, a full model of the vehicle was analyzed under different working loads and the most severe loading condition was selected for this study. Then, a detailed $$ {\text{U}}^* $$ index analysis was performed on the structure to evaluate the load transfer for both loading and reaction forces. Based on the results of this analysis, parts with questionable stiffness were located and a design modification was proposed to improve the structural behavior. In addition, to verify the computer model and conclusions of the $$ {\text{U}}^* $$ index analysis, the structure was tested physically under same loading condition. Finally, the proposed modified design of the structure was analyzed with $$ {\text{U}}^* $$ index theory, and using the design criteria suggested in the theory, it was shown that the new design has great potential for better performance and more efficient load transfer.