A Proposed Model for Predicting Clamp Load Loss Due to Gasket Creep Relaxation in Bolted Joints

Housari, Basil A.; Alkelani, Ali A.; Nassar, Sayed A.

doi:10.1115/1.4005387

Cited by 11 publications

(10 citation statements)

References 5 publications

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“…Clamping force lose due to gasket creep relaxation should be estimated based on the service life of the flange connection, to ensure that all the flange bolts are able to maintain good performance. The clamping force attenuation equation caused by gasket creep relaxation 33 is given as…”

Section: Elastic Interaction and Gasket Creep Looseningmentioning

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:

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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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Section: Elastic Interaction and Gasket Creep Looseningmentioning

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:

View full text Add to dashboard Cite

show abstract

“…Further, according to equation (18), it is easy to derive the displacement equilibrium equation for the n-bolt joint…”

Section: Impact Of Bolt Stress Relaxation On Preload Redistributionmentioning

confidence: 99%

“…By taking the stiffness effect into account, Housari et al. 18 proposed an improved model to simulate the behavior of gasket creep relaxation to predict the residual clamp load and provide a solution to provide the desired level of steady state residual clamp load. Nechache et al.…”

Section: Introductionmentioning

confidence: 99%

“…Abboud et al 17 proposed a novel strain hardening model at room temperature for investigating gasket creep relaxation, and the solution can predict the steady-state gasket pressure. By taking the stiffness effect into account, Housari et al 18 proposed an improved model to simulate the behavior of gasket creep relaxation to predict the residual clamp load and provide a solution to provide the desired level of steady state residual clamp load. Nechache et al 19 proposed an analytical approach based on the strain-hardening rule to estimate the bolt load loss by considering the creep effect of bolts and flange used at high temperature.…”

Section: Introductionmentioning

confidence: 99%

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Modeling and numerical analysis of multi-bolt elastic interaction with bolt stress relaxation

Liu

et al. 2016

Proceedings of the Institution of Mechanical Engineers, Part C:

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Multi-bolt joint distributed around the connecting members are generally adopted to meet the high-performance assembly requirements in aerospace, energy and power industries. However, the initial preload could be low due to non-optimized preload sequence and bolt stress relaxation, especially at elevated temperature. Thus, it is necessary to take elastic interaction and bolt stress relaxation into account before jointing. In this article, a general multi-bolt elastic interaction with bolt stress relaxation is modelled analytically. First, the multi-bolt joint is characterized by ‘spring-node’ model and elastic interaction stiffness. Second, the bolt residual preload can be estimated according to linear superposition of elastic interaction and bolt stress relaxation under the condition of node displacement equilibrium. Further, the influence of preloading sequence and bolt stress relaxation on residual preload distribution was numerically analyzed using a typical circular ring with 8-bolt joint. Two bolts’ preloading sequences were planned, star sequence and counterclockwise sequence, respectively. The bolt creep simulation time was set as 10 h using the power-model at intermediate temperature. From comparison, the predicted results using the developed model were consistent with the FE simulations both with and without bolt stress relaxation.

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“…Recent studies 8,9 showed that the gasket creep relaxation is more important than the bolt/joint material relaxation. Housari et al 10 proposed an improved mathematical model to predict the clamp load loss, taking account of gasket behavior, bolt stiffness, and joint stiffness. On the other hand, several studies were concentrated on plastic deformation of fastener and joints to explain the clamp load loss.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on initial loss of tension in bolted joints

Zhu

Hong

Gao

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part C:

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The initial loss of tension in individual bolts after initial tightening obviously affects the level and the stability of the clamp load in bolted joints. A high-precision instrument to analyze the clamp load loss was developed. In this instrument, an Atlas Copco’s high performance spindle with an accuracy of ±2.5% under the conditions of one million duty cycles was used to tighten the test bolts and nuts. A rotary torque-angle transducer was integrated in the tightening spindle to measure the tightening torque. KMR force washer with a repeatability of < ±1% was applied to monitor the clamping force in real time. Using this instrument, the design of experiment analysis was performed to determine the effect of variables on the initial loss of tension. Those variables included the joint materials, the fastener class, the gasket grade, the lubrication, the surface roughness, the tightening speed, and the number of repeated tightening. The results showed that the tightening speed and the number of repeated tightening had a significant effect on the initial loss of tension. Moreover, a process criterion of eliminating plastic deformation was proposed to minimize the initial loss of tension. The findings presented in this paper will be expected to enhance the reliability and the safety of bolted assemblies, especially in critical applications.

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A Proposed Model for Predicting Clamp Load Loss Due to Gasket Creep Relaxation in Bolted Joints

Cited by 11 publications

References 5 publications

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

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

Modeling and numerical analysis of multi-bolt elastic interaction with bolt stress relaxation

Experimental study on initial loss of tension in bolted joints

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