The Junker test, according to DIN 65151, is considered the
most severe vibration test for bolted connections. During the
test, the joint is exposed to transverse movements underneath
the bolt head / nut, while the clamping force is continuously
measured.
The Junker test shows that Nord-Lock washers safely secured
the bolted connection; only a limited amount of tension is initially
lost due to normal settlements. The wedge-locking function is
verified through the clear increase in tension during untightening. All
other bolt locking methods in the test failed to prevent loosening of the joint.
Please click on link below to watch Nord-Lock Junker test video
http://paraye.com/en/video/20-Nord-Lock--Junker-Video.html
http://paraye.com/en/video/19-Nord-Lock.html