LAUSR

In this study, the effect of clamping force on the bolted double-lap joints has been investigated experimentally. The mechanical behavior of the present joint has been divided into several stages based on the sequence of failure. The commencement failure occurred in such joint is the sticking failure, i.e., loose of clamping effect. One of the main objectives of present investigation is to study the effect of tightening torque value (T = 0–30 Nm) on the sticking failure load, i.e., initiation of the relative sliding. Three different geometries (e/D = 1, 2, and 3) have been adopted to get different modes of failure, namely bearing, shear, and tensile. A steel sheet AISI 1006 with fixed width 30 mm and thickness 3 mm was used. The present experimental results showed six different stages identifying the mechanical behavior of the double-lap joint namely; sticking failure, bearing failure, shearing failure, ultimate strength, tensile/shear crack initiation (depending on the value of e/D), and lastly final failure. For e/D = 2 and 3, the maximum value of sticking failure load is obtained at T = 25 Nm, while T = 30 Nm for e/D = 1. Furthermore, for all values of e/D, the values of sticking failure load are approximately the same at T = 30 Nm. In the case of small values of tightening torque (T < 25 Nm), the stiffness of the joint before sticking failure increased by increasing the value of e/D and T. The difference between the stiffness of joints with different values of e/D, e/D = 1–3, decreased by increasing the tightening torque.