Optimal damper placement for critical excitation

✍ Scribed by I. Takewaki

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 425 KB
• Volume: 15
• Category: Article
• ISSN: 0266-8920
• DOI: 10.1016/s0266-8920(99)00033-8

✦ Synopsis

Since earthquake ground motions are very uncertain even with the present knowledge, it is desirable to develop a robust structural design method taking into account these uncertainties. Critical excitation approaches are promising and a new probabilistic critical excitation method is proposed. Different from the conventional critical excitation methods, a stochastic response index is treated as the objective function to be maximized. The energy (area of power spectral density function) and the intensity (magnitude of power spectral density function) are fixed and the critical excitation is found under these restrictions. It is shown that the resonant characteristic of ground motions can be well represented by the proposed critical excitation. An original steepest direction search algorithm due to the present author is applied to the problem of optimal damper placement in structures subjected to the critical excitation. Closed-form expressions of the inverse of the coefficient matrix (tri-diagonal matrix) enable one to compute the transfer function and its derivative with respect to design variables very efficiently. A numerical example of a 6-DOF shear building model is presented to demonstrate the effectiveness and validity of the present method.