Experimental Investigations on the Effects of Torque Tightening on the Fatigue Strength of Double‐lap Simple Bolted and Hybrid (Bolted/Bonded) Joints

Abstract

In this paper, the effects of bolt torque tightening on the fatigue strength of double‐lap simple bolted and hybrid (bolted/bonded) joints have been studied experimentally. To do so, two types of joints, that is, double‐lap simple and hybrid (bolted/bonded) joints, were studied. For each type of joints, three sets of specimens were prepared and subjected to the tightening torque of 1, 2.5 and 5 Nm, and then, fatigue tests were carried out at different cyclic longitudinal load levels. Experimental tests results showed that the hybrid joints have better fatigue performance in comparison with the simple bolted joints. In addition, the investigation revealed the positive role of tightening torque on the fatigue life of both simple and hybrid joints.

Effects of root radius and pitch difference on fatigue strength and anti-loosening performance for high strength bolt–nut connections

“…Similar to the previous papers (Chen et al, 2016; Noda et al, 2016), a 392 kN (400 ton) servo fatigue tester is used, the frequency is set to 5 or 10 Hz, and the mean load Fm is 30 kN. Esmaeili et al found that the tightening torque T can affect the fatigue strength of bolt joints (Esmaeili et al, 2014). To eliminate the effect of tightening torque T , in the fatigue experiments in this study, the tightening torques T = 0.…”

Experimental investigation of multi-material aluminum-to-steel and glass fiber reinforced polymer-to-steel bonded and bolted–bonded connections

“…The crack growth rate in the adhesive was found to be reduced when it enters into the fasteners' clamping zone, resulting to an improvement of the fatigue resistance of the hybrid joint. In their experimental analysis and numerical simulations on aluminum alloy 2024-T3 loaded in double lap configurations, Esmaeili et al (2014a;2014b;2014c; and Samaei et al (2016) also found a better fatigue performance of hybrid joint compared to simply bolted joints. Their investigation also revealed the positive effect of tightening torque on the fatigue life of bolted and hybrid joints.…”