Comparative Analysis of an Elastic 2 Degree of Freedom Half Car Model with a Rigid 2 Degree of Freedom Model

Ride quality is concerned with the feel of the passenger in the environment of moving vehicle. It is one of the key indices in determining comfort levels of a vehicle. Although, “ride comfort” evaluation is subjective in nature, researchers have developed mathematical models to study and evaluate vehicle ride performance. Some popular models for vehicle ride analysis are - quarter car model, 2 DOF and 4 DOF half car model. These models model the chassis as a rigid body. This work removes this assumption and models the chassis as a flexible beam on a spring damper system at the front and rear using Euler beam theory. This elastic model has 2 DOF - vehicle bounce and pitch, and has been compared with the rigid 2 DOF model. Euler beam theory and Lagrangian mechanics are used to derive the equations of motion. Finite element method is being used to validate this model. Experimental validation of the natural frequencies of this flexible beam is presented.