Changing behavior of friction coefficient for high strength bolts during repeated tightening

Liu, Zhifeng; Zheng, Mingpo; Yan, Xiaohong; Zhao, Yongsheng; Cheng, Qiang; Yang, Congbin

doi:10.1016/j.triboint.2020.106486

Cited by 32 publications

(14 citation statements)

References 27 publications

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“…Good level of accuracy between numerical and experimental results was observed in the linear region of the graph. The numerical non-linear behaviour and the test curve fit deviation form value (0,0) could be caused by the free run-down stage when the nut and sleeve are adjusting during A parabolic deviation has also been observed by Liu et al [18] up to a torque level of 20%, the authors attributed this behaviour to deflection of the bearing surfaces which increases the friction torque. Ganeshmurthy and Nassar [13] identified two zones in the torque-preload relationship for nonparallel contact joints; the first zone ends at about 15% of the total torque and it is justified by the fact that the wedge angle is consumed by the rotated bolt head at the beginning of tightening.…”

Section: Model Validationmentioning

confidence: 68%

“…In the literature, nut factor ranges for standard bolts are found to be dependent on the materials of the connected members. An approximated value of 0.2 has been provided by various authors for typical un-lubricated mid-size steel fasteners [15,16,17,18]. For blind bolts, the value of 0.3 has been used by different authors [19,20,21].…”

Section: Theoretical Relation Between Torque and Preloadmentioning

confidence: 99%

See 1 more Smart Citation

Experimental and numerical analysis of preload in Extended Hollo-Bolt blind bolts

Cabrera

Tizani²,

Ninić³

et al. 2021

Journal of Constructional Steel Research

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Section: Model Validationmentioning

confidence: 68%

Section: Theoretical Relation Between Torque and Preloadmentioning

confidence: 99%

Experimental and numerical analysis of preload in Extended Hollo-Bolt blind bolts

Cabrera

Tizani²,

Ninić³

et al. 2021

Journal of Constructional Steel Research

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“…Given the importance of preload [1][2][3], various methods have been devised for its measurement during the tightening process [4][5][6][7]. The tribological conditions of the threaded joint play a major role in achieving the precise preload value [8]. Consistent preload with a variation of ± 3 % was obtained when the bolt head area was lubricated prior to each torque application [9].…”

Section: Introductionmentioning

confidence: 99%

“…Tightening and loosening threaded joints is simple, however, the tribological characteristics of a threaded joint (coefficient of friction) depend on the method of its formation [10,11]. By separating them, no damage is generated on the parts of the joint, even after a large number of tightenings [8,9,12,13].…”

Section: Introductionmentioning

confidence: 99%

The influence of thread screw parameters on the efficiency of threaded joints

Ristivojević¹,

Dimić²,

Kolarević³

2023

tribomat

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Non-movable threaded joints (bolted connections) and movable threaded joints (power screws) are subassemblies that have a large field of application in the mechanical industry. With these subassemblies, a part of the input energy in the form of torque is spent on overcoming friction on the contact sliding surfaces. These energy losses mostly depend on the geometric and tribological characteristics of the threaded joint. Compared to bolted joints, power screws consume significantly more energy to perform their elementary function. Bolted joints have a much larger field of application in the mechanical industry. In the case of bolted joints metric thread is the most common, and in power screws, threaded joints with a trapezoidal thread. Accordingly, this paper analyses the effects of the coefficient of friction and geometric and kinematic parameters on the energy efficiency of trapezoidal and metric threaded joints. The performed analysis can be used to select the optimal parameters of the threaded joints from the aspect of energy efficiency during the design of new or reconstruction of existing machine structures.

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“…No matter what kind of tightening methods are used, the dispersion of bolt clamping force seems to be unavoidable. The nut factor which is used to characterize the dispersion of clamping force is affected by many factors, [17][18][19][20][21] such as dimension and material of fastener, thread treatment, whether lubrication is used or not, washer type, etc. The dispersion of clamping force obtained by torque control method is about ± 25%.…”

Section: Introductionmentioning

confidence: 99%

A multi-bolt tightening method based on elastic interaction coefficient and gasket creep relaxation

Zheng

Liu

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part C:

Self Cite

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Flange connections are widely used in various mechanical components. The most important purpose of tightening for flanged bolts is to achieve designed clamping force for the maintenance of overall performance. In this work, a multi-bolt tightening algorithm is proposed based on elastic interaction coefficient and gasket creep relaxation. Firstly, dispersion of the individual bolt clamping forces for torque control method is considered in the algorithm. Relationship between the nut factors of the flange bolts in multi-pass tightening is established through experiment. Subsequently, the elastic interaction coefficient matrix was updated during the multi-pass tightening process to reduce the error. Two cases, without gasket and silicone gasket, are considered in the multi-bolt tightening experiment. Without gasket, the elastoplastic deformation at the initial stage after tightening will also cause a loss of clamping force. When using gasket, the clamping force loss due to gasket creep relaxation is more pronounced. Through experimental verification, the proposed multi-bolt tightening algorithm are able to achieve the target range of designed clamping forces and reduce its dispersion. Finally, the main influencing factors of the multi-bolt tightening are analyzed to provide a reference for the design of flange connections.

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Changing behavior of friction coefficient for high strength bolts during repeated tightening

Cited by 32 publications

References 27 publications

Experimental and numerical analysis of preload in Extended Hollo-Bolt blind bolts

Experimental and numerical analysis of preload in Extended Hollo-Bolt blind bolts

The influence of thread screw parameters on the efficiency of threaded joints

A multi-bolt tightening method based on elastic interaction coefficient and gasket creep relaxation

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