scholarly journals A Review of NDT/Structural Health Monitoring Techniques for Hot Gas Components in Gas Turbines

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 711 ◽  
Author(s):  
Frank Mevissen ◽  
Michele Meo
Keyword(s):  
Structural Health Monitoring ◽  
Gas Turbine ◽  
Health Monitoring ◽  
Gas Turbines ◽  
Failure Modes ◽  
Combustion Chambers ◽  
Monitoring Techniques ◽  
Structural Health ◽  
Advantages And Disadvantages ◽  
Turbine Vanes

The need for non-destructive testing/structural health monitoring (SHM) is becoming increasingly important for gas turbine manufacturers. Incipient cracks have to be detected before catastrophic events occur. With respect to condition-based maintenance, the complex and expensive parts should be used as long as their performance or integrity is not compromised. In this study, the main failure modes of turbines are reported. In particular, we focus on the turbine blades, turbine vanes and the transition ducts of the combustion chambers. The existing monitoring techniques for these components, with their own particular advantages and disadvantages, are summarised in this review. In addition to the vibrational approach, tip timing technology is the most used technique for blade monitoring. Several sensor types are appropriate for the extreme conditions in a gas turbine, but besides tip timing, other technologies are also very promising for future NDT/SHM applications. For static parts, like turbine vanes and the transition ducts of the combustion chambers, different monitoring possibilities are identified and discussed.

scholarly journals POST-EVENT PLASTIC FAILURE ANALYSIS OF SHEAR FRAMES FROM THEIR PRE-EVENT ELASTIC RESPONSE

2019 ◽  
Author(s):  
Arzhang Alimoradi
Keyword(s):  
Structural Health Monitoring ◽  
Closed Form ◽  
Health Monitoring ◽  
Early Warning Systems ◽  
Closed Form Expression ◽  
Monitoring Techniques ◽  
Plastic Failure ◽  
Structural Health ◽  
Plastic Mechanism ◽  
Failure Loads

We demonstrate that plastic failure loads of shear frames can be inferred from their elastic ambient response. The interstory plastic mechanism force is derived for moment-resisting (rigid) frames as a function of two measured elastic (low-amplitude) frequencies. Structural health monitoring techniques are traditionally devised for “post-event” assessment of structures after exposure of a facility to a potentially damaging loading event such as strong earthquakes or blasts. The knowledge of induced damage, its location, and severity in an otherwise functioningstructure, as important as it is, may be too late for precautionary preparations. Naturally, one is interested in identification of potential failure mechanisms and indicators prior to damaging events when a structure is responding to environmental loads elastically. Are post-event plastic failure loads identifiable from the pre-event ambient response? We answer this question by first deriving interstory shear stiffness values from a set of measured ambient frequencies that are then incorporated into post-elastic equilibrium equations for a closed-form expression of failure loads as a function of measured frequencies. We test our procedure using a typical shear frame example as proof of concept. To extend the relevance and applicability of the proposed procedure we consider uncertainties associated with the measured and estimated quantities and assess their effects in our model output. The closed-form solutions presented allow study of fully-stressed designs and we present the optimal stiffness distribution for such designs as another example. It is anticipated that temporal relevance of structural health monitoring techniques to “pre-event” assessment will be extended in the near future to such promising technologies as earthquake early warning systems.

scholarly journals Structural health monitoring of two-way slabs based on random decrement technique

2021 ◽  
Author(s):  
Azita Pourrastegar
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Failure Modes ◽  
Ambient Vibration ◽  
Experimental Investigations ◽  
Monitoring Method ◽  
Structural Health ◽  
Random Decrement Technique ◽  
Random Decrement ◽  
Extent Of Damage

The current research attempts to explore the feasible use of a Structural Health Monitoring method for a two-way slab system through the effective vibration based damage diagnostic technique of Random Decrement (RD). Experimental investigations have been conducted on a total of four reinforced concrete two-way slab specimens. The slabs behaviour was examined under static loading. The results were presented in terms of load-deflection relationship at service and ultimate load, crack pattern and failure modes. At each stage of loading, the ambient vibration excitation test has been performed to investigate the extent of damage at the cracking, yield, and ultimate states through changes in dynamic parameters obtained from RD signatures. Additional applications of RD technique were performed on two-way slabs, first, to explore the location of damage by Multi-Channel Random Decrement using FBG sensor arrays. Secondly, RD technique was utilized to evaluate the extent of damage under successive equal dynamic impacts.

scholarly journals Inspection and Structural Health Monitoring techniques for Concentrated Solar Power plants

2016 ◽  
Vol 85 ◽  
pp. 1178-1191 ◽  
Author(s):  
Mayorkinos Papaelias ◽  
Liang Cheng ◽  
Maria Kogia ◽  
Abbas Mohimi ◽  
Vassilios Kappatos ◽  
...  
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Power Plants ◽  
Solar Power ◽  
Concentrated Solar Power ◽  
Monitoring Techniques ◽  
Structural Health ◽  
Solar Power Plants ◽  
Concentrated Solar Power Plants
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