ABSTRACT
FIGURE6lighteningcurveshowingrelationshipbetweentorqueandfastenerrotationangle.Thegradientofthetorque-anglecurveremainsroughlyconstantuntil yieldoccurs,whenitdropsrapidly.(FromRef.3.)
Bycontrast,thetorquegradientcharacteristicscanbeusedtoensureyieldofthefastener withminimumelongation.Thegradientistheslopeofthetorque-rotationcurveshownin Figure6.Theshapeofthegradientcurveisremarkablyconstantoverawiderangeoffasteners andjoints.Essentially,thegradientrisessharplyassoonasthefastenersnugsthepartstogether, thenplateausduringtighteninganddropsrapidlywhenthefasteneryields.
