The Wind-Induced Vibration Response for Tower Crane Based on Virtual Excitation Method
The Dynamics characteristic of Tower Crane is complicated under the wind excitation which complicates the wind-induced vibration response analysis. The random wind-induced response analysis of tower crane is presented based on finite element method and Virtual Excitation Method. The pulsating wind loads are changed into multiple-point correlation stationary excitation. This papers uses Davenport's wind speed spectrum which does not change with height, and considers multiple-point correlation of wind-induction. The Tower Crane is employed as a numerical example, the response spectra and Mean Square Root (RMS) of the tower crane is obtained by wind-induced vibration. The results indicate that the vibration of the tower crane has a large response in low frequency and the One-third Octave acceleration RMS is lower, the influences of the wind-induced vibration on comfort are analyzed.
Pseudo-excitation method for vibration analysis of wind-excited structures
Abstract The pseudo-excitation method, in which random excitations are mathematically represented by a series of harmonic loads, is developed for vibration analysis of wind-excited large civil engineering structures of closely spaced natural frequencies or equipped with discrete damping devices. By using this method, all cross-correlation terms between normal modes in a structural response can be retained naturally, and the non-orthogonal structural damping or stiffness properties can be handled accurately. The principle and algorithm of the pseudo-excitation method are introduced in this paper for structures with and without control devices. The accuracy of the method is validated through the comparison with the transfer matrix method. Two example buildings are presented to demonstrate the advantages of the suggested method.
Tradeoffs and limitations in statistically based image reconstruction problems.
TRADEOFFS AND LIMITATIONS IN STATISTICALLY BASED IMAGE RECONSTRUCTION PROBLEMS