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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.

Ride is considered to be one of the criteria for evaluating the performance of a vehicle. However, the evaluation of ride quality of a car varies from person to person. There are many mathematical models which are used to study vehicle ride dynamics. The development of electronics, sensors and actuators has enabled the use of control systems to enhance the ride quality of a vehicle. This work deals with some of the commonly used ride models viz. Quarter Car model, 2 Degree of Freedom (DoF) Half Car Model and 4 DoF Half Car Model. A complete analysis of these models from a designer's perspective, e.g., variation of suspension stiffness, damping coefficient etc. is being presented. The response of these models to random excitation is being studied. The above mentioned models are based on the rigid body assumption. They do not incorporate a tire model which takes into account the stiffness and damping properties of the tire.