Bearing Friction Torque in Bolted Joints

Nassar, Sayed A.; Barber, Gary C.; Zuo, Dajun

doi:10.1080/05698190590899967

Cited by 68 publications

(30 citation statements)

References 4 publications

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“…Oskouei analysed the stress of aircraft structural double-lapbolted joints by using the finite-element method [19]. Nassar proposed a method of calculating the bearing friction forces on the rotating contact surface of threaded fasteners [20]. In this section, we focus on validating the proposed dynamic reliability models and analysing the influences of the variation in statistical characteristics of material parameters on the reliability and failure rate of explosive bolts.…”

Section: Numerical Examplesmentioning

confidence: 99%

Dynamic Reliability Analysis of Mechanical Components Based on Equivalent Strength Degradation Paths

Gao¹,

Yan²,

Xie³

et al. 2013

SV-JME

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In the design stage of mechanical components, the uncertainty in both the environmental load and the material parameters needs to be taken into consideration and a safety margin is required to guarantee the intrinsic reliability of mechanical components. The safety factor is comprehensively used in the practical design of mechanical components, which is industry specific and determined by the experience of engineers. However, the empirical safety factor cannot quantify the uncertainty and risk in mechanical design. Therefore, reliability analysis of mechanical products has gained more and more popularity [1] to [3].Reliability is defined as the probability that a product performs its intended functions without failure during a specified time period. For mechanical components, the load-strength interference (LSI) model is the most important analytical method in reliability assessment. The conventional LSI model is essentially a static reliability model. However, gradual failure of mechanical components commonly exists in practical engineering due to the strength degradation caused by corrosion, wear, erosion creep, etc. As pointed out by Martin, constructing reliability models considering strength degradation is an important issue for reliability estimation and further research on generalized methods for the dynamic reliability analysis of mechanical components is imperative [4].To overcome the shortcomings of conventional LSI models, reliability models based on stochastic process theory are investigated in which load and strength are modelled as two stochastic processes. Lewis [5] analysed the time-dependent behaviour of a 1-out-of-2: G redundant system by combining the LSI model with a Markov model. Geidl and Saunders [6] introduced time-dependent elements into the reliability equation to estimate the reliability. Somasundaram and Dhas [7] put forward a generalized formula to estimate the reliability of a dynamic parallel system, in which components equally shared the load. Noortwijk and Weide [8] developed a reliability model, in which load and strength are described as two stochastic processes. Labeau et al. proposed the framework of a dynamic reliability platform and identified its main constituents [9]. Zhang et al. analysed the main methods for dynamic reliability estimation of nuclear power plants, which include discrete dynamic event trees and Monte Carlo simulation [10]. Slak analysed production planning and scheduling, cutting tools and material flow process, and manufacturing capacities [11]. Barkallah et al. proposed a method for process planning to determine the tolerance for manufacturing with statistical tools [12].As a matter of fact, the reliability models based on stochastic process theory, such as the timedependent model, Markov model, etc, are the most important tools for dynamic reliability analysis. The Markov models are mainly used for dynamic reliability analysis of electronic elements and multi- Dynamic Reliability Analysis of Mechanical Components Based on Equivalent Strength Degradat...

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Section: Numerical Examplesmentioning

confidence: 99%

Dynamic Reliability Analysis of Mechanical Components Based on Equivalent Strength Degradation Paths

Gao¹,

Yan²,

Xie³

et al. 2013

SV-JME

View full text Add to dashboard Cite

show abstract

“…The effective bearing friction radius can be obtained from the calculation results from Nassar's theory [14]. In that research, four scenarios of underhead load distribution are discussed (i.e., uniform underhead load, linearly decreasing load, exponentially decreasing load, and sinusoidal underhead load).…”

Section: Analytical Modelmentioning

confidence: 99%

“…Other pressure distributions considered would simulate contact stress concentration at the edge of the fastener hole or represent the zero pressure conditions at minimum or maximum radii of the contact area. Nassar's theoretical equations [14] can be listed below, where − means the theoretical calculation result of .…”

Section: Analytical Modelmentioning

confidence: 99%

An Analytical Model for Rotation Stiffness and Deformation of an Antiloosening Nut under Locking Force

Jiang

Hong

Shao

et al. 2014

International Journal of Rotating Machinery

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Screw fasteners are undoubtedly one of the most important machine elements due to their outstanding characteristic to provide a high clamping force just with a simplified design. However, the loosen vibration is their inherent and inevitable fault. The friction locking approach is one of the basic locking fastener categories by enhancing the bearing load on the contact surface of thread by applying a locking force on an antiloosening nut. This locking force may cause more severe deformation in the nut. The contact stress distribution on the nut would be changed and that can cause the variation of the friction torque for the bolt joint. However, there exists no established design calculation procedure that accounts for the rotation deformation and its stiffness of the antiloosening nut under the locking force. The main objective of the work is to develop an analytical solution to the rotation deformation problem encountered in the antiloosening nut. The proposed model is supported by comparison with numerical finite element analysis of different sizes of joint elements and different applied forces.

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“…It is generally between 2 and 3 for most flanged heads and nuts. 13 In this study, FEA models with three different values of g (1.57, 2.47, and 2.92) were built to evaluate the quantitative effect of g on r b . The bearing pressure distribution under different values of g obtained from FEA is shown in Figure 6.…”

Section: Effect Of the Ratio Of R B-max To R B-minmentioning

confidence: 99%

“…Since r bÀmin is commonly close to D/2, equation (5) is usually reduced to equation (6). 13 The effective bearing contact radius can also be calculated using equation (4), based on the assumed bearing pressure distributions. The most commonly used assumption of the bearing pressure distribution is a uniform distribution.…”

Section: Appendixmentioning

confidence: 99%

Calculation of the effective bearing contact radius for precision tightening of bolted joints

Gong

Liu

Ding

2016

Advances in Mechanical Engineering

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Torque control is usually the only method for tightening bolts in some precision assembly applications. However, the scatter of the torque-tension relationship may significantly decrease the accuracy of the preload, which conflicts with the high requirement for mechanical accuracy in such precision assemblies. An important, but often ignored, factor affecting the accuracy of the torque-tension relationship is the effective bearing contact radius. In this article, a threedimensional finite element model of a typical bolted joint was developed to obtain the actual bearing pressure distribution, based on which the effective bearing contact radius can be further calculated. Then, a parametrical study was conducted to systematically investigate the effects of various geometrical, material, and frictional factors on the effective bearing contact radius. Based on the numerical results, a comprehensive and quantitative evaluation of the relative accuracy of each traditional method of calculating the effective bearing contact radius was made. In particular, it was found that the effective bearing contact radius, calculated based on the assumption of uniform bearing pressure distribution, was always relatively accurate regardless of the geometrical, material, and frictional conditions considered. This study will be helpful in increasing the accuracy of preload, thus ensuring mechanical accuracy and quality for precision assemblies.

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Bearing Friction Torque in Bolted Joints

Cited by 68 publications

References 4 publications

Dynamic Reliability Analysis of Mechanical Components Based on Equivalent Strength Degradation Paths

Dynamic Reliability Analysis of Mechanical Components Based on Equivalent Strength Degradation Paths

An Analytical Model for Rotation Stiffness and Deformation of an Antiloosening Nut under Locking Force

Calculation of the effective bearing contact radius for precision tightening of bolted joints

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