An Experimental Study of Self-Loosening of Bolted Joints

Jiang, Yanyao; Zhang, Ming; Park, Tae-Won; Lee, Chu-Hwa

doi:10.1115/1.1767814

Cited by 92 publications

(44 citation statements)

References 8 publications

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“…However, this ideal clamping behaviour is hard to maintain due to time-dependent features such as changes in material properties and the condition of contact surfaces [19,20,57,58]. The self-loosening process starts with the gradual relaxation of initial preload.…”

Section: Failure Analysis Of Ltts Subject To Static Loads Bolted Connmentioning

confidence: 99%

Structural Analysis of Lattice Steel Transmission Towers: A Review

Chen¹,

Ou²

2016

J Steel Struct Constr

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Lattice Transmission Towers (LTT) and the associated transmission line systems are important infrastructure in modern society. Due to the complicated load conditions and the nonlinear interaction among the large number of structural components, accurate structural analysis of the LTT systems has been a challenging topic for many years. Still today there are some gaps between research and industrial practice. This paper presents a summary of research outcomes from current literature. Recent developments in structural modelling and failure prediction technology are reviewed in terms of connection joints, individual members and structural systems subjected to static and dynamic loads. The advantages and disadvantages of different approaches have been compared. Finally, the knowledge gaps, associated challenges and possible research directions are highlighted.

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Section: Failure Analysis Of Ltts Subject To Static Loads Bolted Connmentioning

confidence: 99%

Structural Analysis of Lattice Steel Transmission Towers: A Review

Chen¹,

Ou²

2016

J Steel Struct Constr

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“…There has been much research on this topic. Self-loosening mechanisms [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] and their various influencing factors [17][18][19][20][21] were studied through experiments, theoretical analyses and numerical simulation. A variety of measures were proposed to prevent self-loosening, such as chemical locking [21], step lock bolt (SLB) [22], and double-nut [8,23].…”

Section: Introductionmentioning

confidence: 99%

Anti-loosening performance of coatings on fasteners subjected to dynamic shear load

et al. 2017

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This paper investigates the self-loosening of threaded fasteners subjected to dynamic shear load. Three kinds of typical coatings, PTFE, MoS 2 , and TiN applied to bolts and nuts, are tested in this investigation. The study experimentally examines the loosening mechanisms of fasteners and assesses the anti-loosening performance of the three tested coatings based on their tightening characteristics, loosening curves, and the damage of thread surface. Additionally, the anti-loosening performance of the three coatings is compared under different load forms. The results indicate that the PTFE and MoS 2 coatings have significant anti-loosening effect, whereas the anti-loosening performance of TiN coating is not satisfactory. It is also found that an appropriate increase of the initial tightening torque can significantly improve the anti-loosening effect. In addition, the microscopic analyses of PTFE and MoS 2 coating reveal that a reduced initial tightening torque leads to fretting wear on the thread contact surfaces of fasteners, thereby aggravating the damage.

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“…The initial loss of the clamping force was attributed to the repeated twist of the nut relative to the bolt shank because of the slippage between the bolt and nut threads. Yanyao Jiang and Ming Zhang [6,7] proposed that bolted joints will occur self-loosening based on the experiments, and revealed that the self-loosening process can be divided into two distinguishable stages. The first stage is featured by a short and sharp clamping force reduction with no relative rotation between the nut and the bolt.…”

Section: Introductionmentioning

confidence: 99%

Self-loosening Analysis of Bolted Joints

Xu¹,

Yang²,

Yu³

2017

dtetr

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Abstract. Bolted joint is one of the most widely used connections because of relatively simple structure, reliability, easy disassembly and maintenance. However, self-loosening of bolted joints under cyclic external loading is still an unsolved issue and need to make a further research. As is known to all, the self-loosening process can be divided into two distinguishable stages under cyclic transverse loading. The first stage is featured by a short and sharp clamping force reduction with no relative rotation between the nut and the bolt. The loss of the clamping force is due to the accumulation of local cyclic plastic deformation at the root of the engaged thread, which is account for no more than 10-15%. Therefore, the second stage is the primary cause of self-loosening. In this study, a further research on the second stage self-loosening of bolted joints is presented by the ways of combining theoretical analysis with the three-dimensional finite element simulation. The nature of the second stage self-loosening of bolted joints lies in: 1) the variation of the contact pressure between the engaging thread surfaces, 2) lateral micro-slip between the engaging thread surfaces. Both of them result in an apparent slip between the engaging thread surfaces of bolt and nut which finally leads to the self-loosening of bolted joints. In addition, the effects of preload, amplitude of cyclic transverse loading and the friction coefficient of engaging surfaces on self-loosening are studied by the finite element simulation. Moreover, a reasonable explanation of the trend about the self-loosening of bolted joints is given. The corresponding results are very important for the bolted design. It can be concluded that reasonable preload may improve the ability of bolted joints resisting to self-loosening.

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An Experimental Study of Self-Loosening of Bolted Joints

Cited by 92 publications

References 8 publications

Structural Analysis of Lattice Steel Transmission Towers: A Review

Structural Analysis of Lattice Steel Transmission Towers: A Review

Anti-loosening performance of coatings on fasteners subjected to dynamic shear load

Self-loosening Analysis of Bolted Joints

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