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.
Dynamic Reliability Analysis of Tower Crane with Wind Loading
The wind-induced dynamic reliability of tower cranes was studied. A linear filter autoregressive (AR) model is used to simulate the time history of multidimensional fluctuating wind samples, and the corresponding wind load is applied to the finite element model of tower crane to analyze the wind vibration response. Based on Poisson process method, wind vibration reliability analysis of tower crane is carried out.The results show that under the action of wind speed of 20m/s, the probability of strength reliability is over 0.99, and the structural strength reserve of this type of tower crane is relatively sufficient; the displacement reliability is 0.98, when the wind speed is large, the displacement reliability decreases obviously, and the stiffness reserve is slightly insufficient.
Laminar heat or mass transfer in rectangular channels and in cylindrical tubes for fully developed flow: comparison of solutions obtained for various boundary conditions
Abstract A comparison is made of results obtained with various boundary conditions at the wall of the channels. By comparing blood Sherwood numbers for finite wall resistance with those for constant concentration boundary condition only a small variation is found for various points along the blood channel.