scholarly journals THE AUTOMATIC HANDLING OF DATA FROM A LARGE-SCALE DOG RADIATION EXPERIMENT USING A GENERAL PURPOSE COMPUTER

1965 ◽  
Author(s):  
M H Dipert ◽  
W P Norris ◽  
J A Pagels
Keyword(s):  
Large Scale ◽  
General Purpose ◽  
General Purpose Computer ◽  
Purpose Computer

Vibration Control of Flexible Multibody Aircraft During Touchdown Impacts

1987 ◽  
Vol 109 (3) ◽  
pp. 270-276 ◽  
Author(s):  
A. A. Shabana ◽  
R. D. Patel ◽  
A. DebChaudhury ◽  
R. Ilankamban
Keyword(s):  
Dynamic Analysis ◽  
Vibration Control ◽  
Random Process ◽  
Large Scale ◽  
Passive Control ◽  
Multibody System ◽  
General Purpose ◽  
Flexible Multibody ◽  
General Purpose Computer ◽  
Purpose Computer

A method is presented for the dynamic analysis and vibration control of large scale flexible multibody aircraft during the touchdown impacts and rollover motion. The rollover motion is simulated by modeling the uneven runway profile as a stationary zero mean space dependent random process defined by its spectral shape. The prescribed motions at the two landing gears will then represent a different time dependent random process with spectral shapes changing with the change in velocity of the aircraft. Composite materials which provide higher stiffness-to-weight ratios are used as a passive control system to reduce the aircraft vibration. The results of the numerical example presented showed that the use of composites can have a significant effect on attenuating the vibration of the aircraft during the touchdown impact and rollover motion. The numerical results are obtained using the general purpose computer program DAMS (Dynamic Analysis of Multibody System).

An Efficient Method for Calculating Damped Critical Speeds of Rotor-Bearing Systems

1991 ◽  
Author(s):  
D. Z. Wang ◽  
D. L. Taylor
Keyword(s):  
Element Model ◽  
General Purpose ◽  
Critical Speeds ◽  
Rotor Bearing ◽  
General Purpose Computer ◽  
System Equations ◽  
Newton Raphson ◽  
Reported Data ◽  
Derivatives Of ◽  
Purpose Computer

Abstract This paper describes an analytical approach for calculating the damped critical speeds of multi-degree-of-freedom rotor-bearing systems. It is shown that to calculate the critical speeds is equivalent to finding the roots of a proposed matrix algebraic equation. The technique employes a Newton-Raphson scheme and the derivatives of eigenvalues. The system left eigenvectors are used to simplify the calculations. Based on this approach, a general-purpose computer program was developed with a finite element model of rotor-bearing systems. The program automatically generates system equations and finds the critical speeds. The program is applied to analyze a turbomachine supported by two cylindrical oil-film Journal bearings. The results are compared with reported data and the agreements are very good.

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