ROBUST DESIGN OF A TWO DEGREE FREEDOM SYSTEM DUE TO THE PARAMETER UNCERTAINTY

A method based on the robust design optimization is presented to handle the structural uncertainty problems.The variations caused in dynamic performance can be expressed by the mean response and the standard deviation of the performance.The robust optimization approach,based on a multi-objective and non-deterministic method,attempts to both optimize the mean performance and minimize the variance of the performance simultaneously.The best possible design optimization is chosen by a trade-off decision.An example of robust design of a two degree freedom system is used to effectively illustrate the application in dynamics.The mass and stiffness uncertainty in the main system as well as the uncertainty of the mass,stiffness and damping in the absorber are considered all together in order to minimize the displacement response of the main system within a wide band of excitation frequencies.The robust optimization results show a significant improvement in performance compared with the conventional solution recommended from vibration textbooks.It is indicated that robust design methods have great potential for application in structural dynamics to deal with uncertainty problems.