Bolted joints are the most common type of mechanical connections, and improving the anti-loosening performance of bolts for the reliable performance of mechanical and building structures is highly significant.,Because of the lack of sufficient theoretical basis for the evaluation and design of anti-loosening bolts, a quantitative evaluation model exhibiting the following two evaluation criteria for anti-loosening bolts is introduced: bolt rotation angular acceleration criterion and critical transverse load criterion. Based on the relationship among bolt tension, transverse load and bolt rotation angular acceleration, a critical transverse load calculation model is put forward, and the mechanism by which the critical transverse load increases with the increase of bolt tension is revealed.,Based on the above model, a new type of anti-loosening bolt is designed, which generates additional bolt tension when the transverse load increases, and then improves the critical transverse load of the bolt. The effectiveness of the new type of anti-loosening bolt is verified by theoretical calculations and experiments.,The proposed model and method set a preliminary theoretical foundation for the evaluation of bolt anti-loosening performance and the design of a new anti-loosening bolt.

Mechanism and quantitative evaluation model of slip-induced loosening for bolted joints

Uniform bolt load is critical to achieve leak-free service in pressure vessel gasketed joints. In a previous work, the authors presented the tetraparametric assembly method, which enabled to obtain...

Generalization of the tetraparametric assembly method for the optimization of bolt tightening sequences in ring-type joints:

Offshore wind turbines in shallow waters are predominantly installed using a monopile foundation, onto which a transition piece and wind turbine are attached. Previously, the monopile to transition piece (MP-TP) connection was made using a grouted connection, however, cases of grout failure causing turbine slippage, among other issues, were reported. One solution is to use bolted ring flange connections, which involve using a large number of M72 bolts to provide a firm fixing between the MP-TP. It is in the interest of offshore wind operators to reduce the number of maintenance visits to these wind turbines by maintaining a preload (Fp) level above the minimum requirement for bolted MP-TP connections. The present study focuses on the effect of the tightening sequence on the Fp behaviour of M72 bolted connections. A detailed finite element (FE) model of a seven-bolt, representative segment of a monopile flange was developed with material properties obtained from the available literature. Three analyses were made to examine the effect on Fp after tightening, including the initial Fp level applied to the bolts, the tightening sequence and the effect of an additional tightening pass.

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Analysis of tightening sequence effects on preload behaviour of offshore wind turbine M72 bolted connections

Deflection modeling of a manipulator for mechanical design

Study of bolt load scatter due to tightening sequence

Efficient assembly of bolted joints under external loads using numerical FEM

Static structural behaviour of wire bearings under axial load: Comparison with conventional bearings and study of design and operational parameters

Wire twisting stiffness modelling with application in wire race ball bearings. Derivation of analytical formula and finite element validation

Wire-race bearings are a non-conventional type of bearings where the rolling process takes place over a race shaped in a wire. This design allows building the rings with lighter materials and innovative ring designs. Despite the wide range of applications where wire-race bearings can be the best option, no specific analysis tools have been developed yet. There are several analytical tools for conventional bearings, which obtain the stiffness, the effect of the preload and the static load capacity among others. In this work a simplified analytical model is proposed for a wire-race ball bearing, and comparatively validated via Finite Element Analysis.

Iñigo Martín

Papers

Efficient assembly of bolted joints under external loads using numerical FEM

Static structural behaviour of wire bearings under axial load: Comparison with conventional bearings and study of design and operational parameters

Wire twisting stiffness modelling with application in wire race ball bearings. Derivation of analytical formula and finite element validation

Analytical Model for the Estimation of Axial Stiffness and Contact Results in Wire Race Ball Bearings

Structural modeling of crossed roller wire race bearings: Analytical submodel for the roller-wire-ring set