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In this paper, experimental study and FEA simulation are performed to investigate the effect of three different methods for joining dissimilar metal coupons in terms of their strength and load transferring capacity. The joining techniques considered include adhesive bonding, bolting and hybrid bolting-and-bonding. Elastic-plastic material model with damage consideration is used for each of the joint components. Traction-separation rule and failure criterion is defined for adhesive. Load transfer capacity and the failure mode are assessed for each type of joining. Joint strength is examined in terms of the effects of adhesive property, bolt preload level, and friction coefficient. Results show that load transferred and failure mechanism vary significantly between samples with different joint methods; preload evolution in bolt changes with friction coefficient; hybrid joint generally has advantage over the other two methods, namely, bolting-only and bonding-only.

This paper presents an experimental investigation of the effect of threaded fastener condition on the low cycle fatigue behavior of a tightened metric fastener under a fully reversed, cyclic transverse load. The test set-up subjects tightened, threaded fasteners to the combined effect of axial, torsional, bending, and transverse shear loading. The two conditions of the fasteners were “as received” and “ultrasonically cleaned and oiled”. Fatigue performance at three different bolt tension levels was investigated. Based on preliminary testing arbitrarily selected amplitude of 0.05 inches was used for the cyclic transverse displacement, at a frequency of 10 Hz. A Scanning Electron Microscope (SEM) was used to assess the failure mode on a bolt fracture surface. The bolt stresses are sensitive to both thread and under head friction characteristics.

This paper investigates the reliability of tightening automotive weld studs, using experimental techniques. During the nut installation on weld studs, only a small amount of the applied torque is used to produce the required clamp load in the joint. While a large amount of the input torque is lost in overcoming friction between the sliding surfaces. Large scatter in the stud tension often results from the normal friction variations. As a result, the weld stud becomes more susceptible to a pull-through failure mode especially in thin sheet metal applications. The torque-angle signature during stud tightening is analyzed to assess the strength and quality of the weld stud joint. The effect of the weld stud thread type, stud coating, sheet metal thickness and stud material on the torque-tension relationship of weld studs is investigated. An experimental procedure and test set up are proposed to test weld studs.