scholarly journals Multicrack Localization in Rotors Based on Proper Orthogonal Decomposition Using Fractal Dimension and Gapped Smoothing Method

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Zhiwen Lu ◽  
Dawei Dong ◽  
Shancheng Cao ◽  
Huajiang Ouyang ◽  
Chunrong Hua
Keyword(s):  
Fractal Dimension ◽  
Proper Orthogonal Decomposition ◽  
Orthogonal Decomposition ◽  
Smoothing Method ◽  
The Finite Element Method ◽  
New Approach ◽  
Rotor Systems ◽  
Crack Configuration ◽  
Proper Orthogonal ◽  
Robust To Noise

Multicrack localization in operating rotor systems is still a challenge today. Focusing on this challenge, a new approach based on proper orthogonal decomposition (POD) is proposed for multicrack localization in rotors. A two-disc rotor-bearing system with breathing cracks is established by the finite element method and simulated sensors are distributed along the rotor to obtain the steady-state transverse responses required by POD. Based on the discontinuities introduced in the proper orthogonal modes (POMs) at the locations of cracks, the characteristic POM (CPOM), which is sensitive to crack locations and robust to noise, is selected for cracks localization. Instead of using the CPOM directly, due to its difficulty to localize incipient cracks, damage indexes using fractal dimension (FD) and gapped smoothing method (GSM) are adopted, in order to extract the locations more efficiently. The method proposed in this work is validated to be effective for multicrack localization in rotors by numerical experiments on rotors in different crack configuration cases considering the effects of noise. In addition, the feasibility of using fewer sensors is also investigated.

scholarly journals Spectral proper transformation and application to gust response prediction of structures

2007 ◽  
Vol 29 (1) ◽  
pp. 25-36
Author(s):  
Le Thai Hoa ◽  
Nguyen Dong Anh
Keyword(s):  
Proper Orthogonal Decomposition ◽  
Response Prediction ◽  
Orthogonal Decomposition ◽  
Decomposition Techniques ◽  
Random Loading ◽  
Engineering Structures ◽  
New Approach ◽  
Cable Stayed Bridge ◽  
Proper Orthogonal ◽  
Gust Response

Random turbulent loading on engineering structures which immersed in the atmospheric turbulent flow is often represented as the multi-dimensional and/ or multivariate Gaussian random loading processes. Gust response prediction, however, usually burdens a lot of computational difficulties due to turbulent loading projection on the generalized structural coordinates. In these cases, the decomposition techniques must be required to decouple the multi-variate turbulent loading into the independently generalized turbulent forces, then is associated with the generalized structural modes. This paper will present the proper orthogonal decomposition using the spectral proper transformation in the frequency domain to decouple the multi-variate turbulent loading processes. New approach in the gust response prediction of structures will be formulated with numerical example of cable-stayed bridge.

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