Predictive stress and crack growth monitoring in cracked superheater headers

1994 ◽  
Author(s):  
S.K. Pascoe
Keyword(s):  
Crack Growth ◽  
Growth Monitoring

scholarly journals Nonlinear Crack Growth Monitoring

2000 ◽  
Author(s):  
Donald E. Welch ◽  
Lee M. Hively ◽  
Ray F. Holdaway
Keyword(s):  
Crack Propagation ◽  
End Of Life ◽  
Crack Growth ◽  
National Laboratory ◽  
Growth Monitoring ◽  
High Quality ◽  
Oak Ridge ◽  
The Past ◽  
Fiberglass Composite ◽  
Nonlinear Crack

Abstract Structures subject to crack growth spend 90–95% of their lifetime in nucleation of very tiny flaws into measurable crack sizes. Due to the large variation in initial flaw sizes and the mathematics of flaw growth, the fatigue lifetimes, even of high-quality structures, can vary by a factor of as much as 10 to 20 even in a small fleet. This large variation in fatigue lifetimes leads to conservative statistics, which often prompts the premature retirement or overhaul of structures, since they focus on the weakest members of the fleet, while the remainder of the fleet is sound. In the past two years, Oak Ridge National Laboratory (ORNL) has developed a new Griffith energy-based technique that can provide useful warning of the impending failure of a structure due to end-of-life crack propagation. This technique has been demonstrated by test and analysis in fiberglass composite for tension-tension fatigue.

Health Monitoring of the Aircraft Structure during a Full Scale Fatigue Test with Use of an Active Piezoelectric Sensor Network

2015 ◽  
Vol 220-221 ◽  
pp. 328-332
Author(s):  
Michal Dziendzikowski ◽  
Krzysztof Dragan ◽  
Artur Kurnyta ◽  
Sylwester Klysz ◽  
Andrzej Leski
Keyword(s):  
Signal Processing ◽  
Damage Detection ◽  
Crack Growth ◽  
Fatigue Test ◽  
Piezoelectric Sensor ◽  
Full Scale ◽  
Growth Monitoring ◽  
Aircraft Structure ◽  
System Functioning ◽  
Signal Processing Methods

The paper presents an approach to develop a system for fatigue crack growth monitoring and early damage detection in the PZL – 130 ORLIK TC II turbo-prop military trainer aircraft structure. The system functioning is based on elastic waves propagation excited in the structure by piezoelectric PZT transducers. In the paper, a built block approach for the system design, signal processing as well as damage detection is presented. Description of damage detection capabilities are delivered in the paper and some issues concerning the proposed signal processing methods and their application to crack growth estimation models are discussed. Selected preliminary results obtained during the Full Scale Fatigue Test thus far are also presented.

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