Modal response analysis of multi-support structures using a random vibration approach

2015 ◽  
Vol 44 (13) ◽  
pp. 2241-2260 ◽  
Author(s):  
Ernesto Heredia-Zavoni ◽  
Sandra Santa-Cruz ◽  
Francisco L. Silva-González
Keyword(s):  
Random Vibration ◽  
Response Analysis ◽  
Support Structures ◽  
Modal Response

Response Analysis of Secondary Systems With Nonlinear Supports

1991 ◽  
Vol 113 (4) ◽  
pp. 524-531 ◽  
Author(s):  
T. Igusa ◽  
R. Sinha
Keyword(s):  
Random Vibration ◽  
Natural Frequencies ◽  
Hysteresis Loops ◽  
Nonlinear Behavior ◽  
Equivalent Linearization ◽  
Response Analysis ◽  
Analysis Method ◽  
Secondary System ◽  
Secondary Systems ◽  
Insight Into

This paper introduces a simplified random vibrations analysis method of linear secondary systems with nonlinear supports. The method separates, as much as possible, the nonlinear analysis of the supports from the linear analysis of the remainder of the secondary system. Equivalent linearization is used to generate response-dependent linear properties of the supports directly from hysteresis loops. These properties are then combined with the properties of the secondary system, and a response analysis is performed using mode combination. The analysis procedure is simpler than standard random vibration methods, and for narrow-band responses, it accurately models nonlinear behavior. In addition, the procedure uses equivalent modal quantities, such as natural frequencies and damping ratios, which provide insight into the effects of the nonlinear supports on the secondary system.

Dynamic Modeling and Stability Analysis of a Dual-Rotor Wind Turbine

2018 ◽  
Author(s):  
Oliver T. Filsoof ◽  
Morten H. Hansen ◽  
Anders Yde ◽  
Xuping Zhang
Keyword(s):  
Wind Turbine ◽  
Dynamic Modeling ◽  
Wind Turbines ◽  
Floquet Theory ◽  
Equations Of Motion ◽  
Response Analysis ◽  
Modal Response ◽  
Asymmetric Rotor ◽  
Modal Property ◽  
Fidelity Model

Various modal analysis methods are available for single-rotor wind turbines, but there is no report and guidance on the modal property analysis of multi-rotor wind turbines. This paper presents a dynamic modeling method for the modal response analysis of a wind turbine with two three-bladed isotropic rotors. The equations of motion are derived using Lagrange’s equations and are further linearized at a steady-state equilibrium. To avoid using Floquet Theory to remove the periodic coefficients, multi-blade coordinates are utilized. Comparison between the numerical simulations and a high-fidelity model in HAWC2 shows agreements in terms of modal frequencies. The results shows that the whirling modes splits into symmetric and asymmetric rotor modes.

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