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In this paper, the effect of bearing friction and the hole clearance on the out-of-plane surface deformation in bolted joints is studied. Series of clamp load-deformation correlations are established for different lubrication conditions and hole clearance values by using both FEA and experiment methods. To study the effect of bearing friction coefficient, values that range from 0.1 to 0.4 are adopted in the FEA model. Three lubrication conditions are used in experiments; namely, clean bolts, oil lubricated bolts and grease lubricated bolts. In order to investigate the effect of hole clearance, four different hole diameters are used in FEA model with M8 bolts; namely, 8.8mm, 9mm, 9.25mm and 9.7mm, three of them are used in the experiments. Experiments are conducted on a single-bolt joint made of an aluminum plate that is fastened with an M8 class 10.9 button head socket screw.

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.

Factorial analyses of stress concentrations at the bolt thread root based on finite element models are presented in this paper. A full bolted joint including a bolt, a nut, and fastened members were modeled using solid elements. Bolt and bolt threads were meshed in detail in 3-dimensional mode, with their interaction being only the direct load transfer between the bolt and nut. Statistical design of experiments was conducted to identify the factors and two-factor interactions, which may have impact on the stress concentration at the bolt thread root.

This study involves the investigation of the sensitivity of the torsional stiffness of a bolt-together heavy truck chassis to variations in tight/loose conditions for various combinations of individual bolts or groups of bolts. The behavior of the chassis, which features several hundred threaded fasteners as the primary means of connecting the cross members to the longitudinal beams, is studied using the Hierarchical Evolutionary Engineering Design System (HEEDS) in connection with the finite element program (ABAQUS) for performing a multiple-run analysis. A novel analysis approach involving a systematic segregation of the bolts is introduced. First, the bolts that are used for connecting the components of the chassis are divided into various sets. Each set represents a number of individual bolts in each joint between the longitudinal beams and the various cross members.

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.