scholarly journals An overview of PST for vibration based fault diagnostics in rotating machinery

2018 ◽  
Vol 211 ◽  
pp. 01004 ◽  
Author(s):  
T. Haj Mohamad ◽  
C. Nataraj

In general, diagnostics can be defined as the procedure of mapping the information obtained in the measurement space to the presence and magnitude of faults in the fault space. These measurements, and especially their nonlinear features, have the potential to be exploited to detect changes in dynamics due to the faults. We have been developing some interesting techniques for fault diagnostics with gratifying results. These techniques are fundamentally based on extracting appropriate features of nonlinear dynamical behavior of dynamic systems. In particular, this paper provides an overview of a technique we have developed called Phase Space Topology (PST), which has so far displayed remarkable effectiveness in unearthing faults in machinery. Applications to bearing, gear and crack diagnostics are briefly discussed.

2019 ◽  
Vol 8 (3) ◽  
pp. 393-401 ◽  
Author(s):  
T. Haj Mohamad ◽  
Foad Nazari ◽  
C. Nataraj

Abstract Background In general, diagnostics can be defined as the procedure of mapping the information obtained in the measurement space to the presence and magnitude of faults in the fault space. These measurements, and especially their nonlinear features, have the potential to be exploited to detect changes in dynamics due to the faults. Purpose We have been developing some interesting techniques for fault diagnostics with gratifying results. Methods These techniques are fundamentally based on extracting appropriate features of nonlinear dynamical behavior of dynamic systems. In particular, this paper provides an overview of a technique we have developed called Phase Space Topology (PST), which has so far displayed remarkable effectiveness in unearthing faults in machinery. Applications to bearing, gear and crack diagnostics are briefly discussed.


2018 ◽  
Vol 241 ◽  
pp. 01011 ◽  
Author(s):  
T. Haj Mohamad ◽  
C. A. Kitio Kwuimy ◽  
C. Nataraj

This paper presents the application of Extended Phase Space Topology (EPST) and conventional statistical time domain features in the diagnostics of various bearing faults in rotating machinery systems. Bearings with various health statuses operating under multiple motor loads and speeds are analyzed. The results indicate remarkable performance in detecting anomalous behavior and in identifying faults with virtually perfect accuracy, recall and precision.


2018 ◽  
Vol 16 (8) ◽  
pp. 416-428 ◽  
Author(s):  
Porjan Tuttipongsawat ◽  
Eiichi Sasaki ◽  
Keigo Suzuki ◽  
Takuya Kuroda ◽  
Kazuo Takase ◽  
...  

2017 ◽  
Vol 24 (14) ◽  
pp. 3148-3172
Author(s):  
Riya C George ◽  
Sudib K Mishra

The applicability of the phase space interrogation (PSI) methodology for structural health monitoring (SHM) is limited on account of the fact that the structure needs to be excited by a low dimensional chaotic signal. The present study demonstrates that the phase space interrogation can still be applied to structures subjected to ambient/moderate wind excitations. Key to this extension is the relative low dimensionality of the wind-induced structural responses, amenable to phase space embedding by virtue of Takens’ embedding theorem. The so-formed pseudo-attractor is shown to sufficiently reflect the changes in system dynamics induced by structural damage(s). A widely employed damage feature, namely, the changes in phase space topology (CPST) is subsequently employed to the reconstructed attractor to link it with the presence, severity, as well as localization of damage(s). The CPST is established as a legitimate damage-sensitive feature by studying its variability with alternative damage scenarios in a multistoried frame building subjected to wind excitations. The performance of the methodology is demonstrated under different degrees of noise contamination in the measured responses as well as varying intensity of wind speed. The statistical robustness of the procedure is also assessed. The numerical findings are supported by the evidence from a limited number of experimental investigations carried out on a model building with inflicted damage scenarios. The wind loadings for the tests are simulated using a wind tunnel testing facility. Finally, a simple analysis is presented that establish the viability of the phase space analysis analytically.


Author(s):  
Lavish Pamwani ◽  
Amit Shelke

Shockwave is a high pressure and short duration pulse that induce damage and lead to progressive collapse of the structure. The shock load excites high-frequency vibrational modes and causes failure due to large deformation in the structure. Shockwave experiments were conducted by imparting repetitive localized shock loads to create progressive damage states in the structure. Two-phase novel damage detection algorithm is proposed, that quantify and segregate perturbative damage from microscale damage. The first phase performs dimension reduction and damage state segregation using principal component analysis (PCA). In the second phase, the embedding dimension was reduced through empirical mode decomposition (EMD). The embedding parameters were derived using singular system analysis (SSA) and average mutual information function (AMIF). Based, on Takens theorem and embedding parameters, the response was represented in a multidimensional phase space trajectory (PST). The dissimilarity in the multidimensional PST was used to derive the damage sensitive features (DSFs). The DSFs namely: (i) change in phase space topology (CPST) and (ii) Mahalanobis distance between phase space topology (MDPST) are evaluated to quantify progressive damage states. The DSFs are able to quantify the occurrence, magnitude, and localization of progressive damage state in the structure. The proposed algorithm is robust and efficient to detect and quantify the evolution of damage state for extreme loading scenarios.


1998 ◽  
Vol 59 (4) ◽  
pp. 671-682 ◽  
Author(s):  
G. M. ZASLAVSKY

For low-dimensional Hamiltonian systems with chaotic dynamics, we discuss the differences in the kinetic description, and the necessity of windowing of the time and parameter space, which is imposed by the differences in the phase-space topology and by the stickiness of trajectories at island boundaries.


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