Vertical Cylinders of Arbitrary Section in Waves

1978 ◽  
Vol 104 (3) ◽  
pp. 309-324
Author(s):  
Michael de St. Q. Isaacson
Keyword(s):  
Arbitrary Section ◽  
Vertical Cylinders

Hydrodynamic Coefficients of Vertical Cylinders of Arbitrary Section

1991 ◽  
Vol 113 (2) ◽  
pp. 109-116 ◽  
Author(s):  
M. Isaacson ◽  
T. Mathai
Keyword(s):  
Vertical Cylinder ◽  
Vertical Direction ◽  
Numerical Approach ◽  
Offshore Structures ◽  
Three Dimensions ◽  
Method Of Integral Equations ◽  
Square Cylinders ◽  
Added Masses ◽  
Arbitrary Section ◽  
Vertical Cylinders

The calculation of added masses and damping coefficients of a large surface-piercing vertical cylinder of arbitrary section extending to the seabed and undergoing harmonic oscillations is described. The linear radiation problem in three dimensions is reduced to a series of two-dimensional problems in the horizontal plane by the use of appropriate eigenfunctions that represent the variation of the velocity potential in the vertical direction. Each of these is solved by a numerical approach based on the method of integral equations. Comparisons are made with an analytic solution available for the case of a circular cylinder. Results are also provided for square cylinders, and the application to typical offshore structures subject to base motions is discussed.

Probabilistic Analysis of Random Structural Intensity for Structural Members under Stochastic Loadings

2015 ◽  
Vol 12 (03) ◽  
pp. 1550013 ◽  
Author(s):  
Siu-Siu Guo ◽  
Dongfang Wang ◽  
Zishun Liu
Keyword(s):  
Energy Flow ◽  
Early Stage ◽  
Structural Members ◽  
Structural Intensity ◽  
Dynamic Loadings ◽  
Arbitrary Section ◽  
Stationary Loading ◽  
Fpk Equation ◽  
Definition Of ◽  
Probability Density Function Pdf

The concept of structural intensity (SI) is extended to the random domain by introducing a physical quantity denominated random structural intensity (RSI). This quantity is formulated for mechanical systems whose dynamical responses are stochastic due to random excitations. In order to fully characterize the stochastic behavior of a system under random loadings, it is imperative to obtain the probability density function (PDF) of RSI. Based on the elastic theory and the definition of SI, RSI is expressed as functions of system responses. In general, the PDF of system responses is governed by Fokker–Planck–Kolmogorov (FPK) equation under the assumption that random dynamic loadings are idealized as white noise excitations. Therefore, the PDF of RSI is derived with the joint PDF of system responses. In the present study, four demonstrating cases of beams and plates under separately concentrated and uniform random loadings are studied to investigate the properties of RSI. Stationary and non-stationary PDFs of RSI at arbitrary section of beam and plate are obtained. Numerical results show that the PDF of RSI is transient at early stage of stationary loading and then converges to the exact stationary ones as time increases. With the obtained PDFs of RSI, energy transmission path over the beam and plate can be determined, which is guided from the locations with lower probabilities of RSI to the ones with higher probabilities of RSI. Furthermore, virtual energy flow sinks on the plate and beam can be found, which are identified by the locations with the maximum probabilities of RSI.

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