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Characteristics of Prevailing Torque Nuts in Aircraft Latches Under Repeated Uses
Received date: 2013-07-05
Revised date: 2013-10-26
Online published: 2013-11-16
Prevailing torque nuts are widely used to fix the quick release covers on aircraft surfaces. But the unscrew torque decreases and locking mechanism may fail with repeated uses of the nuts. Parameters that may affect the maximum unscrew torque are first qualitatively analyzed which takes into consideration material strain hardening, low-cycle fatigue and frictional changes. The slotting gap value is considered to be a significant parameter that affects the repeated use characteristics when nuts of a specific material are fixed, and experiments are carried out to study it. Nuts with 3 different designed slotting gap values are screwed in and out to simulate the multiple reuses. The maximum unscrew torques are measured and torque-reuse curves are obtained. The test results show that, with the increase of reuse times, the maximum unscrew torque fluctuated at first, and, after a certain degree of recovery (a period of 50<N<200), decreased again slowly to a steady state during the region of 200<N<1 500.The slotting gap value affected the decrease rate and the best slotting gap value is obtained from the three tested designs.
WANG Songwei , CHENG Xiaoquan , PAN Wen , ZHANG Jikui . Characteristics of Prevailing Torque Nuts in Aircraft Latches Under Repeated Uses[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2014 , 35(3) : 788 -794 . DOI: 10.7527/S1000-6893.2013.0443
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