An integrated approach to local ultrasonic monitoring of fastener hole fatigue cracks
نویسنده
چکیده
a crack depth in mm, same as x â measurement system response, 1 – R– A(x) system model for evolving crack depth x A(n) linearised system model at measurement set n B(x) measurement model giving normalised energy ratio R– as a function of crack depth x B(n) linearised measurement model at measurement set n B(R) inverse measurement model giving crack depth x as a function of normalised energy ratio R– c0 linear fit parameter c1 linear fit parameter C multiplicative material constant for Paris’s Law E(n, L) energy of the ultrasonic waveform after the nth measurement set and at an externally applied load of L F geometry correction factor for Paris’s Law G(n) Kalman gain for measurement set n h specimen thickness kT stress concentration factor L externally applied load Lref reference load necessary to fully open cracks m exponential material constant for Paris’s Law M number of measurements in the prediction set for the crack ABSTRACT
منابع مشابه
Simultaneous Ultrasonic Monitoring of Crack Growth and Dynamic Loads during a Full Scale Fatigue Test of an Aircraft Wing
An in situ ultrasonic angle beam method has been developed to detect and size fatigue cracks emanating from fastener holes. The method employs transducers mounted in a pitch-catch configuration on each side of the hole, and the modulation of received signals with load is used to detect and size small fatigue cracks. The focus of this paper is the monitoring of a series of critical fastener hole...
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