Effects of Clamp Force on Fatigue Strength of Aluminum Alloy Bolts

Hashimura, Shinji; Kamibeppu, Kazuki; Nutahara, Tomohiro; Fukuda, Kenji; Miyashita, Yukio

doi:10.1016/j.prostr.2019.12.022

Cited by 9 publications

(4 citation statements)

References 10 publications

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“…Therefore, it should be noted that the stress data plotted beyond the line ((σ m /σ sl )+(σ a /σ w ) > 1) does not represent the real fracture at the bolt thread. Several previous studies investigated the endurance limit after a certain amount of mean stress level (Burguete et al, 1995; Gunn, 1955; Hashimura et al, 2019; Munn et al, 2010). In this paper, the Soderberg line of plain specimen is used to discuss the relative hazard at the bolt roots.…”

Section: Stress and Crack Appearing At Bolt Threadsmentioning

confidence: 99%

Effects of root radius and pitch difference on fatigue strength and anti-loosening performance for high strength bolt–nut connections

Noda

Wang

Oda

et al. 2021

Advances in Structural Engineering

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The fatigue strength improvement and anti-loosening performance are studied experimentally and analytically for JIS M16 bolt–nut connections. Three different root radii are considered coupled with three different pitch differences. The enlarging the bolt root radius improves the fatigue limit of the bolt by more than 30% because both stress amplitude and mean stress can be reduced. Furthermore, suitable pitch difference improves the fatigue limit by more than 25%. This is because under no pitch difference the crack initiation always occurs at No.1 or No.2 threads close to the bolt head causing the final failure; however, under a suitable pitch difference the crack initiation occurs at No.6 or No.7 threads far away from the bolt head. Good anti-loosening performance can be expected for the bolt–nut connections having enlarged root radius because the prevailing torque [Formula: see text] = 19 Nm and the residual prevailing torque [Formula: see text] are not smaller compared to other special bolt–nut connections.

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Section: Stress and Crack Appearing At Bolt Threadsmentioning

confidence: 99%

Effects of root radius and pitch difference on fatigue strength and anti-loosening performance for high strength bolt–nut connections

Noda

Wang

Oda

et al. 2021

Advances in Structural Engineering

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“…Studies have shown that the factor of variation in external loading of VF has a more significant effect on the guaranteed lifetime than the tightening force F. It should be noted that the increase in the tightening force reduces the fatigue strength to a certain limit. After that, the negative effect of the tightening disappears, because at the root of the first tread there is a local plastic deformation [19]. For large tightening forces F, the intensity of falling diagram βΣR0 (ΔF) increases, and for small F, this intensity decreases.…”

Section: Search Of the General Safety Indexmentioning

confidence: 99%

Fatigue Resistance Models of Structural for Risk Based Inspection

Belodedenko¹,

Hanush²,

Baglay³

et al. 2020

Civ Eng J

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The current stage of civil engineering is characterized by special attention to the safety of structures with a long service life. Such objects were designed several decades ago and their safe operation was ensured by significant safety margins. Now this approach to safety has been replaced by the concept of acceptable risk. It forms the basis of a risk based inspection (RBI) maintenance strategy. The transition from preventive maintenance strategies to a technical condition maintenance is substantiated. Complex indicators of technical condition, suitable for RBI- maintenance, are considered. The methodology of the resource safety index (RSI) is proposed. The latter is used as an indicator of risk. Special models of fatigue resistance is required for its control. The purpose of this paper is to build fatigue models for critical structural elements that are serviced according to the RBI concept. Instead of the traditional S-N curve, the lifetime general equation (first model) be used, where by the arguments are the main influence factors. Along with this, a modified ε - N equation is proposed for deformation criteria. The novelty of this equation is that it uses the rate of S-N- curve (slope) obtained in the first model with high cycle fatigue. The second model, combining the results of fatigue tests, is the equation for the dispersion of durability. The third model is the accumulated damage function under overloads. The efficiency of the RSI method is demonstrated by the example of the reliability assessment of the high strength bolts. Thanks to RSI method forecasting, during RBI-maintenance, parts can be used 3-5 times longer than with traditional methods.

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“…Different from other mechanical joining methods, bolt tightening method can give tightening axial force as clamping force on bolted parts. As a result, joining strength of bolted joints is higher than other mechanical joining methods (7,8) . However bolted joints need careful attention to tightening axial force reduction caused by loosening as well as static strength and fatigue strength.…”

Section: Introductionmentioning

confidence: 97%

Influences of Various Parameters on Shear Stiffness of Bolted Joint Subjected to Shear Load

Murai¹,

Watanabe²,

Fukuda³

et al. 2023

Preprint

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Multi-material structures have been required to reduce weight of vehicles in order to improve fuel efficiencies. To realize multi-material structures effectively, we have to select not only the optimum material for each structure but also the optimum joining techniques for each joint. Bolted joints are one of the most popular methods to join dissimilar materials. Various characteristics for the bolted joints had been revealed in the literatures. Especially self-loosening characteristics of bolted joints subjected to shear cyclic load have been still investigated. However it has not been sufficiently investigated which parameters effect on shear stiffness of bolted joints which is subjected to shear load. When two plates are joined by a bolt and a nut, it is important for functionally designing machines to know if the shear stiffness of the joining point is the same as the plate stiffness or not and if the stiffness changes or not. In this study, we have revealed experimentally and analytically the shear stiffness characteristics of bolted joints and which parameters determine the shear stiffness. Washers with different contact areas to the clamped plates were used in the experiments. The results showed that the shear stiffness of bolted joints increases with an increase in the contact area size between washers and clamped parts. The result indicates that the shear stiffness of bolted joint is mainly determined by the bending stiffness that is an easiness of bolted joints to rotate due to shear tensile force rather than the clamping force. But if the slippage occurs between the clamped plates, the shear stiffness of bolted joint markedly decreases. The results also showed that the tensile force with which the clamped plates begin to slip between them depends on the clamp force of bolted joints and the contact area size between the clamped plate and the washers.

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Effects of Clamp Force on Fatigue Strength of Aluminum Alloy Bolts

Cited by 9 publications

References 10 publications

Effects of root radius and pitch difference on fatigue strength and anti-loosening performance for high strength bolt–nut connections

Effects of root radius and pitch difference on fatigue strength and anti-loosening performance for high strength bolt–nut connections

Fatigue Resistance Models of Structural for Risk Based Inspection

Influences of Various Parameters on Shear Stiffness of Bolted Joint Subjected to Shear Load

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