scholarly journals NON LINEAR RESPONSE ANALYSIS EXCITED BY RANDOM INPUT WITH ARBITRARY SHAPE SPECTRUM

2019 ◽  
Vol 84 (757) ◽  
pp. 331-341
Author(s):  
Tomio NAKANO ◽  
Satoshi MATSUDA
Keyword(s):  
Linear Response ◽  
Arbitrary Shape ◽  
Response Analysis ◽  
Random Input ◽  
Non Linear

Conceptual Analysis of the Non-Linear Forced Response of Aerodynamically Unstable Bladed-Discs

2013 ◽  
Author(s):  
Roque Corral ◽  
Juan Manuel Gallardo ◽  
Rahul Ivaturi
Keyword(s):  
Time Domain ◽  
Linear Response ◽  
Harmonic Excitation ◽  
Friction Model ◽  
Forced Response ◽  
Response Analysis ◽  
Non Linear ◽  
Aerodynamic Instability ◽  
Time Domain Response ◽  
The Time Domain

The response of aerodynamically unstable tuned bladed-discs with non-linear friction dissipation at blade-root attachments due to harmonic external excitation is studied. The bladed-disc is modeled using a simple mass-spring system and the effect of friction is modeled using a micro-slip friction model. The response is computed in time domain using a Runge-Kutta scheme. The time domain response is decomposed to obtain the evolution of traveling waves in the bladed-disc. Parametric studies have been conducted to study the non-linear response at different vibration amplitudes at high and low engine orders of excitation. It is seen that the non-linearity due to friction gives rise to a complicated interaction between the synchronous response of the system due to harmonic excitation and the non-synchronous response of the system due to aerodynamic instability. For low excitation levels the system behaves as in the pure flutter regime where a single, or at most a few, aerodynamically unstable modes may be found in the final state when a limit cycle is reached. When the forcing is large enough the aerodynamic instability is suppressed and only the non-linear response of the excited mode may be seen. It is concluded that the superimposition of the flutter and forced response analysis in terms of vibration amplitude is not valid and leads to prediction of vibration amplitudes significantly larger than that obtained when both phenomena are simulated together.

Application of Environmental Contour Lines on a Flexible Riser

2010 ◽  
Author(s):  
Gro Sagli Baarholm ◽  
Sverre Haver
Keyword(s):  
Time Domain ◽  
Linear Response ◽  
Contour Line ◽  
Exceedance Probability ◽  
Response Analysis ◽  
Wave Direction ◽  
Flexible Riser ◽  
Peak Period ◽  
Non Linear

This paper is concerned with estimating the response value corresponding to an annual exceedance probability. In principle, this response needs to be obtained by combining the response statistics in all sea states and wave headings. The probability distribution for a given sea state and wave direction, specified by the significant wave height, Hs, the peak period, Tp, and wave direction, β, can be obtained by frequency domain analysis for linear response. Time domain simulations are, in general, required to obtain the stochastic structure of a non-linear response quantity. To limit the statistical uncertainty, the time domain simulations must be sufficiently long. Therefore, a simplified method is necessary to improve the efficiency of the direct calculation of the long-term response value in the non-linear case. A method to determine the long-term extremes by considering only a few short term sea states is outlined. The sea states have a certain probability of occurrence and are identified by a contour line in the (Hs,Tp) plane. This will make possible practical estimation of the extreme loads the structure is exposed to. The contour line approach is merely suggested as a method for predicting load- and response maxima corresponding to a given annual exceedance probability without having to carry out a full long term analysis. The advantage with this concept is that the environmental and response analysis is decoupled. This is very convenient if the problem under consideration is of a very non-linear nature — in particular if characteristic values for design are to be established directly from model tests. The method is an approximate method, but seems to give results of reasonable accuracy for most problems. The purpose of the present paper is to present the contour line method applied to estimate responses on a flexible riser, lazy wave configuration, located in the North Sea.

Flow velocity and light level drive non-linear response of seagrass Zostera noltei to ammonium enrichment

2016 ◽  
Vol 545 ◽  
pp. 109-121 ◽  
Author(s):  
B Villazán ◽  
FG Brun ◽  
V González‑Ortiz ◽  
F Moreno‑Marín ◽  
TJ Bouma ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Linear Response ◽  
Light Level ◽  
Zostera Noltei ◽  
Non Linear

Non-linear response of stomata in Pinus koraiensis to tree age and elevation

Trees ◽  
2012 ◽  
Vol 26 (4) ◽  
pp. 1389-1396 ◽  
Author(s):  
Yumei Zhou ◽  
Marcus Schaub ◽  
Lianxuan Shi ◽  
Zhongling Guo ◽  
Anan Fan ◽  
...  
Keyword(s):  
Linear Response ◽  
Tree Age ◽  
Pinus Koraiensis ◽  
Non Linear

Preliminary investigation fo the non-linear response of image intensifiers used for gamma-ray imaging

2013 ◽  
Author(s):  
David Fastje ◽  
H. Bradford Barber ◽  
Vaibhav Bora ◽  
Daniel Lemieux ◽  
Brian Miller ◽  
...  
Keyword(s):  
Linear Response ◽  
Gamma Ray ◽  
Preliminary Investigation ◽  
Non Linear ◽  
Gamma Ray Imaging ◽  
Image Intensifiers

Non-linear response of YBa2Cu3O7−y thin film microstrip resonator at microwave frequencies

1992 ◽  
Vol 84 (12) ◽  
pp. 1107-1110 ◽  
Author(s):  
R. Pinto ◽  
Ravi Kumar ◽  
Navdeep Goyal ◽  
P.R. Apte ◽  
S.P. Pai ◽  
...  
Keyword(s):  
Thin Film ◽  
Linear Response ◽  
Microstrip Resonator ◽  
Microwave Frequencies ◽  
Non Linear
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