Year

1999

Degree Name

Master of Engineering (Hons.)

Department

Department of Mechanical Engineering

Abstract

This thesis discusses the general piecewise linear damped system with multiple degrees of freedom, a model drawn from the simplilSed suspension systems of passenger cars where the dampers (dashpots) have extension damping coefficients that are different from their compression damping coefficients. The simplified suspension system of the passenger car is built as a model with eight degrees of freedom which include the vertical motion of the seat / passenger (human body), the bounce, pitch, and roll motions of the car body, and the vertical motions of the four wheels. Harmonic excitation is applied to the model that vibrates in a series of different linear stages caused by its dampers' characteristic. Lagrange's equation is used to derive the model's system matrices in every linear stage. Fourth-order Runge-Kutta formula is used for the numerical calculation and MATLAB is used for the computer simulation. The numerical computing results are explained through the general piecewise linear damped system with multiple degrees of freedom by analytical deriving where the state-space method is used in each linear stage and then the analytical solutions of all linear stages are combined by determining their constants. In this way, the whole picture of the system's motion can be understood. Some usefiil conclusions are provided, one of which is that the system will vibrate around the deviated positions from its static equilibrium.

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