A reduced-order beam modelling approach of BIW for torsional and bending stiffness optimization

Noise, Vibration, and Harshness (NVH) simulations of vehicle bodies are crucial for assessing performance during the design phase. However, these simulations typically require detailed computer-aided design (CAD) models and are time-consuming. In the early stages of vehicle development, when only high-level vehicle sections are available, designing the body-in-white (BIW) structure to meet target values for bending and torsional stiffness is challenging and often requires multiple iterations. To address these challenges, this study deploys a reduced-order beam modelling approach. This method involves identifying the beam-like sections and major joints within the BIW and calculating their sectional properties (area, area moments of inertia along the plane’s independent axes, and torsion constant). These components form a simplified skeleton model of the BIW. Load and boundary conditions are applied to the suspension mount locations at the front and rear of the vehicle, and torsional and bending stiffness are calculated. The results demonstrated good accuracy compared to conventional NVH simulations. A Design of Experiments (DoE) study is also conducted on the major sections of the BIW to identify the critical beams necessary for achieving stiffness targets. Additionally, the effect of changing materials in identified sections is studied to assess potential weight reductions while maintaining target stiffness values. This approach significantly accelerates the process and proves to be highly effective in determining stiffness parameters during the conceptual stages of vehicle design.