In automotive product development, design and development of the chassis plays an important role since all the internal and external loads pass through the vehicle chassis. Durability, NVH, Dynamics as well as overall vehicle performance is dependent on the chassis structure. Even though passenger vehicle chassis has a ladder frame or a monocoque construction, small commercial vehicle chassis is a hybrid chassis with the cabin welded to the ladder frame. As mileage is critical for sale of SCVs, making a light-weight chassis is also important. This creates a trade-off between the performance and weight which needs to be optimized.
In this study, a parametric beam model of the ladder frame & the cabin of the vehicle is created in COMSOL Multiphysics. The structure has been parameterized into the long member & crossmember geometry & sections. The model calculates the first 12 natural frequencies, global stiffness, and weight. It has been validated and further used for optimization study for the above-mentioned trade-off. The results give direction on critical crossmembers where the cross-sections should not be compromised and give a direction which crossmembers will be able to take the defined loads with a decrease in sectional property. Similarly, for long members it identifies critical load carrying zones and gives a scope of optimizing the cross-sectional properties. The study aids the design engineer in the development of the chassis. This method of beam modelling and subsequent optimization enhances the chassis performance which in turn also improves the overall vehicle performance.
