scholarly journals Time Saving Method for Measuring VHC Fatigue and Fatigue Crack Growth Data with the Ultrasonic Fatigue Technique

2016 ◽  
Vol 2 ◽  
pp. 3-10 ◽  
Author(s):  
Stefanie E. Stanzl-Tschegg
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Data ◽  
Time Saving ◽  
Ultrasonic Fatigue

An ultrasonic fatigue crack growth monitor and load controller

1975 ◽  
Vol 10 (3) ◽  
pp. 159-162 ◽  
Author(s):  
E H R Wade ◽  
G M C Lee
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Type Specimen ◽  
Load Control ◽  
Growth Data ◽  
Stress Intensity Range ◽  
Growth Increments ◽  
Ultrasonic Fatigue ◽  
Ultrasonic Techniques

The design of an ultrasonic crack follower which continuously monitors the position of a fatigue crack in a 36 mm thick C.K.S. type specimen is described. An open-bottomed ‘tank’ containing a mobile immersion probe is mounted on the top surface of the sample. The probe is used to measure the position of the crack tip by normal ultrasonic techniques; as the crack grows the probe is automatically advanced to keep the reflected signal intensity constant. The probe drive mechanism is geared to two potentiometers, one of which produces an output proportional to the probe position, the other is used to attenuate the load control signal so as to keep the stress intensity range constant. The unit was capable of detecting crack growth increments of 450 μm. The automatic nature of the measurement greatly simplified the collection of fatigue crack growth data.

Effect of Hardness and Tensile Mean Stress on Fatigue Crack Growth in Beryllium Copper

1969 ◽  
Vol 11 (3) ◽  
pp. 343-349 ◽  
Author(s):  
L. P. Pook
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Residual Stresses ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Mean Stress ◽  
Growth Data ◽  
Beryllium Copper

Some fatigue crack growth data have been obtained for age-hardened beryllium copper. The fatigue crack growth rate was found to be very dependent on the hardness and tensile mean stress. This dependence is believed to be associated with the intense residual stresses surrounding Preston-Guinier zones.

Near-Threshold Fatigue Crack Growth at 63Sn37Pb Solder Joints

2002 ◽  
Vol 124 (4) ◽  
pp. 385-390
Author(s):  
Ki-Ju Kang ◽  
Seon-Ho Choi ◽  
Tae-Sung Bae
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Tests ◽  
Lap Joint ◽  
Growth Data ◽  
Micro Structure ◽  
Crack Behavior ◽  
Temperature Aging ◽  
Near Threshold

Fatigue tests were performed using single lap-joint specimens to obtain near-threshold fatigue crack growth data of solder joint under mode-II load. Attention was focused on the effect of high temperature aging and microstructures separately from the intermetallics. As a result, it was shown that the long cast time yielded the intermetallics and microstructures of the solder invariable regardless of aging condition. The granular micro-structure of the air-cooled specimens was shown to be inferior to the laminated micro-structure of the furnace-cooled specimens. Also, transition of fatigue crack behavior with ΔJ and the procedure of fatigue crack propagation from the pre-crack tip were discussed.

Full Size Fatigue Crack-Growth Testing for Girth Welds

2004 ◽  
Author(s):  
Paulo Gioielli ◽  
Jaime Buitrago
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Production Quality ◽  
Small Scale ◽  
Loading Frequency ◽  
Growth Data ◽  
Girth Welds ◽  
Crack Growth Modeling ◽  
Fatigue Crack Growth Testing

Fatigue crack-growth modeling has a significant impact in establishing defect acceptance criteria for the inspection of fracture-critical, girth-welded components, such as risers and tendons. ExxonMobil has developed an experimental technique to generate crack-growth data, in actual welded tubulars, that account for the particular material properties, geometry, and residual stresses. The technique is fully compatible with conventional fracture mechanics models. It uses a series of pre-designed notches made around the welds on a production quality, full-scale specimen that is tested efficiently in a resonant fatigue setup. The crack development from notches is monitored during testing and evaluated post-mortem. Given its simplicity and high loading frequency, the technique provides growth data germane to the component at hand at a lower cost and faster than standard, small-scale tests.

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