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The purpose of this paper is to give a brief introduction of helical spring locked washer along with extensive literatures survey on role of helical spring locked washer in bolted joint analysis. It is very small component of bolted joint assembly, but it play vital role in holding the assembly components together. Helical shape of it produces spring effect in the assembly which is used for keeping the assembly in tension and that is lock the assembly under dynamic loading due to vibrations to avoid the accident.

The critical literatures survey identifies role of helical spring locked washer in different areas such as design optimization, mechanism of loosening-resistant components, bolted joint analysis, finite element-based modeling, analysis and simulation. The related literatures show contribution of helical spring washers in evaluation of anti-loosening performance of assemblies as compare to other types of washers.

It proposed that design optimization of helical spring locked washer is needed as it improves the performance in the form of load-deflection characteristics, load bearing capacity and provides the best locking force for optimize functionality.

The originality or value of this paper is to finding research gaps in literatures by dividing literatures into seven different research areas and concentrating the only on role of helical spring locked washer in bolted joint analysis.

The helical spring lock washer (HSLW) is a part of nut bolt joint assembly used in different industries like automobile, aerospace, mechanical, chemical, electrical, electronics, etc. It works as a part of temporary joint and plays important role in loosening behavior of assembly under dynamic (vibrations) conditions. Thus, the purpose of this paper is to investigate the performance of HSLW under different controlled operating conditions in order to satisfy its functional requirement.

In the present investigation, a novel test rig is designed and developed to determine the load-deflection characteristics of HSLWs. The test rig facilitates the controlled linear displacement of the HSLW with predetermined angular rotation of the handle gives the corresponding reaction load on the display. Additionally, the repeatability and reproducibility of the test rig was carried out.

The newly designed and developed test rig is capable enough to differentiate the load-deflection characteristics during compressive loading and unloading of HSLWs. Additionally, the loss of strain energy can be determined from the load-deflection characteristics of HSLW.

The present test rig is designed and developed to investigate the load-deflection characteristics under compressive loading and unloading of HSLW. The test rig has least count of 0.4905 N for load measurement and 0.01389 mm for linear displacement.

The purpose of this paper is to explore the applications and technological details of common components – rings and springs.

The characteristics and applications of compression springs and then extension springs are investigated, and various finishing techniques are reported. Rings ranging from flat washers to snap‐rings, push‐on rings and Smalley rings are presented.

The humble spring may be surprisingly high‐tech, with applications in fuel injection, pacemakers and insulin delivery systems. Springs fulfill shock absorption duties as well as securing tasks, and can pre‐load fixtures to withstand thermal expansion and vibration. Retaining rings are used in heavy duty lifting gear and wind turbines, whilst simple washers elegantly combine wear protection with insulation in securing circuit boards.

The paper highlights the continuing development and surprising strengths of some simple components.

In the current manuscript, the authors examine the Belleville spring with the variable thickness. The thickness is assumed to be variable along the meridional and parallel coordinates of conical coordinate system. The calculation of the Belleville springs includes the cases of the free gliding edges and the edges on cylindric curbs, which constrain the radial movement. The equations developed here are based on common assumptions and are simple enough to be applied to the industrial calculations.

In the current manuscript, the authors examine the Belleville spring with the variable thickness. The calculation of the Belleville springs investigates the free gliding edges and the edges on cylindric curbs with the constrained radial movement. The equations developed here are based on common assumptions and are simple enough to be applied to the industrial calculations.

The developed equations demonstrate that the shift of the inversion point to the inside edge does not influence the bending of the cone. On the contrary, the character of the extensional deformation (circumferential strain) of the middle surface alternates significantly. The extension of the middle surface of free gliding spring occurs outside the inversion. The middle surface of the free gliding spring squeezes inside the inversion point. Contrarily, the complete middle surface of the disk spring on the cylindric curb extends. This behavior influences considerably the function of the spring.

A slotted disk spring consists of two segments: a disk segment and a number of lever arm segments. Currently, the calculation of slotted disk spring is based on the SAE formula (SAE, 1996). This formula is limited to a straight slotted disk spring with freely gliding inner and outer edges.

The equations developed here are based on common assumptions and are simple enough to be applied to the industrial calculations. The developed method is applicable for disk springs with radially constrained edges. The vertical displacements of a disk spring result from an axial load uniformly distributed on inner and outer edges. The method could be directly applied for calculation of slotted disk springs.

The nonlinear governing equations for the of Belleville spring centres were derived. The equations describe the deformation and stresses of thin and moderately thick washers. The variation method is applicable for the disc springs with free gliding and rigidly constrained edges. The developed method is applicable for Belleville spring with radially constrained edges. The vertical displacements of a disc spring result from an axial load uniformly distributed on inner and outer edges.

SELECTING the correct bearing for any particular application involves more than the determination of the correct type and size. It is true that the calculation of the nominal working life will give an indication of the operational life before failure, but this calculation only takes into account the fatigue life of the material. If this theoretical life is to be obtained—and perhaps exceeded—then additional factors must be taken into account when initially designing the bearing arrangement. Lubrication and protection from the operating environment are two very important considerations.

Bolted joints are commonly used to connect structural members. These joints can be disassembled whenever required. Various types of washers are used between nut and the connected member to keep the joints tight. However, these joints often become loose over time under dynamic loading conditions. The purpose of this paper is to know the reasons of loosening of bolted joints and to identify the main parameters that contribute to the bolt loosening, and to verify them with previous work.

This work studies loosening of bolted joint in a test rig under varying tightening torque as well as for various types of washers used as the number of load cycles increases. Four trial runs are taken for each case considered and the average results are found out to minimize possible sources of errors. For the purpose, a specifically made test rig is used which is capable of applying harmonic load on the bolted joint by the lever action.

The study compares the loosening of bolted joint with and without washer, and also under different initial tightening conditions. This study has shown the suitability of the test rig, methodology and parameters for study of loosening in bolted joints. This study presents an indigenous test, capable of applying harmonic load on bolted joint.

The results establish that the methodology and parameters selected were appropriate for the purpose of study of loosening of bolted joints. This study has provided a base line for further work to understand the loosening of bolted joints.

ABB ROBOTICS has, in conjunction with the automotive industry, developed a concept for automatic mounting of cylinder heads which satisfies the industry's increasingly stringent requirements for:

A SPRING is defined as a device for storing and retaining energy. This definition is very much a simplification and every designer should have some idea of what is involved in selection of springs and the design of them where necessary. This article only covers springs made from metallic materials, although mention must be made of the fact that springs may be devised from such materials as glass fibre reinforced plastics, rubber, air and other fluids.

Fasteners, adhesives and sealants are as important to aerospace production as the most sophisticated advances in engine design. Without the correct nuts and bolts, no aircraft can function, or certainly not for long, efficiently and safely. Even the man in the street — as well as his wife and children — was made dramatically aware of this after the Amsterdam air crash last year when numerous daily newspapers clearly explained the function of sheer pins and showed, in large, simplified drawings, how they are used to attach the engines to the wings of the Boeing 747. But even though the proverbial “Man on the Clapham Omnibus” and his schoolboy son know the importance of fasteners in aircraft manufacture and maintenance, the industry itself does not appear to hold them in the same high esteem. Fasteners, it seems, are like discreet waiters in a decent restaurant: you don't notice them until they're missing. In order to compile this feature, we wrote to all known manufacturers and suppliers of fasteners, adhesives and sealants seeking information on products and their applications. Despite the opportunity for publicity, the response was negligible. The subsequent telephoning of non‐respondents (which was most of them) was only marginally more productive. The interesting thing was the air of indifference shown. Many of the companies bluntly said they were not interested — not even in free publicity. One firm even said that it did not need publicity, it never had and it never would. Such self‐sufficiency, though admirable, is hardly indicative of a dynamic, developing company and typified an attitude of many companies in this sector which seemed to spring from a general lack of interest — or pride, perhaps — in what they are doing. At the suggestion of our editor, I contacted the Society of British Aerospace Companies (SBAC) to obtain figures on the quantities and the value of fasteners produced and sold by their member companies. Here, at least, I thought, would be the basis of an article. But here I was wrong. The SBAC does not compile such figures. It is clear from all this that suppliers to the aerospace industry do not take fasteners as seriously as “The Man on the Clapham Omnibus” does. It is equally clear that the companies mentioned on this and the following pages consider fasteners, adhesives and sealants to be very important.