Torque and Angle Controlled Tightening Over the Yield Point of a Screw—Based on Monte-Carlo Simulations

This paper presents a technique, based on Monte-Carlo simulations, of utilizing a screw over its yield point in a controlled fashion, even under simple tightening conditions. The simulations consider the probabilistic nature of different variables necessary to calculate screwed joints. The proposed torque and angle controlled tightening technique can be used in assembly plants as well as in small workshops. The technique predicts permanent elongation, maximum tightening angle, final torque and preload after tightening. Further, a recommendation on the minimum and maximum snug torques prior to application of the angle over the yield point of a screw is also presented.