Comparison of loosening behavior of bolted joints using plain and spring washers with full-threaded and plain shank bolts

Abstract

Bolted joints tend to loosen under dynamic loads. Plain and spring washers are most common to control loosening. Initial tightening torque applied on the joint, at the time of assembly, also plays an important role. It is also known that bolts with shanks snugly fitting in the hole help in the control of loosening. In the present study comparison of plain and spring washer with the case of using no washer, and comparison of the bolt with plain shank with full-threaded bolt have been carried out. The result shows that plain washer is slightly effective to prevent loosening than that of spring washer with a threaded bolt. Whereas, the combination of Plain washer and bolt with plain shank is most effective. It shows that use of plain washer significantly controls loosening, under the three initial tightening conditions of the joint 20% under-tightened, 10% under-tightened and tightened up to rated torque.