Optimizing the Natural Frequencies of Beams via Notch Stamping

Nabeel T. Alshabatat

《Research Journal of Applied Sciences, Engineering and Technology》 4卷14期 (2012/07) Pp. 2030-2035

並列摘要

Natural frequency optimization is important to avoid the coincidence of excitation frequency and natural frequency which causes resonance phenomenon. In this study, the natural frequencies of a beam, with different boundary conditions, are enhanced by stamping V-notches on its surface. These notches alter the local stiffness in the beam while keeping the mass the same. This method is cost-effective in comparison with other Structural Dynamics Modification methods (SDM) because it is a one-step manufacturing method and because it enhances the dynamic behavior of beam structures without additional weight or additional joints. The natural frequencies of notched beam are calculated by finite element method. In particular, ANSYS package is used in building the notched beam models for modal analysis. The effect of notch location and size on the beam fundamental frequency is investigated. The simulation results indicated that creating notches on free-free beam decreases its fundamental frequency, while creating notches on clamped beam may increase its fundamental frequency. The optimal designs of notched beams are presented. The proposed method couples a finite element method for the modal analysis with an optimization technique based on Genetic Algorithm (GA). Three examples are presented to show the optimal design of free-free and clamped notched beams. The optimization results show that V-notch stamping technique is an effective technique to optimize the natural frequencies.

並列關鍵字

Finite element method ； genetic algorithms ； modal analysis ； natural frequency ； optimization ； V-notch