AN ABSTRACT OF THE THESIS OF Jacob Boone, for the Master of Science degree in Mechanical Engineering, presented on 10/28/2010, at Southern Illinois University Carbondale. TITLE: DESIGN, CONSTRUCTION, AND EVALUTAION OF UNIVERSAL FRICTION TESTER MAJOR PROFESSOR: Dr. Peter Filip Many different types of friction testers are currently available for testing specific frictional applications. Of these machines very few have versatility, and of the ones that do, the amount of versatility is limited. Since friction is a property specific to each system, all operating parameters need to match the specific application as closely as possible in order to obtain accurate data. This requires many research facilities to have several specific friction testers in order to provide the necessary testing capabilities. The goal of this project was to design a Universal Friction Tester (UFT) with enough versatility to reproduce most types of sliding friction situations. This was accomplished by providing a wide range of testing capabilities through the use of interchangeable system components. Results show that the UFT provides quality data over its entire operating range. It was shown that normal pressure, sliding speed, temperature and system stiffness all have drastic effects on frictional performance. By using a borosilicate glass disc, the friction surface was viewed in-situ during testing. This allowed insights into true surface temperature and contact area. In conclusion, the UFT can successfully take the place of several friction testers and thus provide many friction research capabilities while requiring fewer resources. The wide range of testing capabilities will allow the UFT to be used as a research tool for many types of advanced friction studies. Some of these may include true surface temperatures, true contact area, influence of conditions on stick-slip phenomenon, and thermo-elastic instabilities.

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Yes / PolyEtherKetone (PEK) is a suitable material for tribological systems which specifically require the properties of high chemical resistance, low component weight, seizure resistance under starved lubrication conditions and operation at higher temperatures than many other engineering polymers can survive. PEK is used with a liquid lubricant at high temperatures and velocities to reduce friction and also to control unstable friction and wear, particularly in the region of the material’s glass transition temperature, Tg. Intermittent and marginal lubrication using representative high temperature synthetic lubricants was applied to high speed, high temperature PEK/steel sliding contacts to determine the effectiveness of lubrication under these conditions. Variations in the stability of the thin lubricant films were observed, particularly under different load conditions. Under low load conditions, the lubricant polarity and the related ability to form a film in the contact was important. Under high load conditions, the thermal stability of the lubricant became more important in retaining stability in the friction and wear mechanisms. Whilst not ideal practice, marginal lubrication of PEK-steel sliding contacts can be achieved by selection of an appropriate lubricant, even in the glass transition region of PEK. / Innovate UK Knowledge Transfer Partnership (KTP) grant, No. 8092.

This report describes the development of a modular friction test rig for threaded fasteners. This device can measure the shank torque and the clamp force during the tightening of threaded bolts, with a size of M3-M14 and clamp length of 30-160mm. The design allows the use of several load and torque cells and the range is up to 100kN clamp load and 200Nm applied torque. The test rig will be used for research purposes by Atlas Copco to determine the frictional characteristics in tightening and will allow the experiments on bolts with several materials, coatings and surface finishes. This report concludes to a design proposal evaluated with analytical methods and a prototype 3D model that demonstrate the working principle of the test rig. The measurements are taken from custom-made sensors that are developed with high standards, are easily interchangeable and can be calibrated individually. In addition, a device is developed to allow the user to change the stiffness of the joint. Finally, a future recommendation is made to allow the measurement of the under-head torque. This proposal is a breakthrough compared to other test rigs, and will assist in verifying the friction measurements and having high precision results. / Denna rapport beskriver utvecklingen av en modulär friktionsprovrigg för gängade fästelement. Den utvecklade enheten kan mäta moment och klämkraft under åtdragning av gängade skruvar, med en storlek mellan M3 och M14 och klämlängd på 30-160mm. Designen möjliggör användning av flera last- och vridmomentceller och intervallet är upp till 100kN klämbelastning och 200Nm påfört vridmoment. Provriggen är en forskningsrigg, och den kommer att användas av Atlas Copco för att bestämma friktionsegenskaperna i åtdragning och möjliggöra experiment på skruvar av olika material, och med olika ytbeläggningar och ytbehandlingar. Denna rapport avslutas med ett designförslag, som utvärderas analytiskt och testprincipen demonstreras med hjälp av en prototyp. Mätningarna tas från skräddarsydda sensorer, som kan kalibreras individuellt och som är enkelt utbytbara. Dessutom är en anordning utvecklad för att tillåta användaren att ändra styvheten hos förbandet. Slutligen ges en rekommendation för en vidareutveckling, som möjliggör mätning av skallmomentet. Detta förslag är ett genombrott jämfört med andra existerande testriggar, och kommer att bidra till att verifiera friktionsmätningarna med hög precision.

La micro fusion laser d'un lit de poudre (SLM) permet la réalisation de pièces complexes avec des microstructuresfines. Cette technologie présente de nombreux avantages mais se heurte encore à une faible disponibilité des poudres d'alliages. En SLM, la pièce est d'abord conçue par CAO (conception assistée par ordinateur), puis construite couche par couche avec un faisceau laser commandé par un ordinateur. Dans ce cadre, le travail effectué dans cette thèse a consisté à étudier et à développer une nouvelle méthode pour réaliser des pièces en alliages et en composites à partir de mélanges de poudres élémentaires, ouvrant ainsi la voie à une grande variété de compositions.Au niveau expérimental le choix s'est porté sur le système aluminium-silicium avec différentes teneurs en silicium (12, 18 et 50% en poids). L'effet de l'ajout d'un champ magnétique statique a aussi été proposé comme un outil supplémentaire de contrôle de la microstructure.Dans le processus de fabrication de pièces par SLM la puissance du laser et la vitesse de balayage déterminent au premier chef la densité, la microstructure, la composition des phases et les propriétés mécaniques du produit. Une analyse systématique de l'effet de ces paramètres sur l'alliage Al - Si fabriqué par SLM à partir de mélanges de poudres est présentée. Des alliages ont été ainsi obtenus pour plusieurs domaines de composition visés correspondant à des applications pratiques (structures légères, système tribologique, emballage électronique, ...).Les microstructures fines obtenues grâce à la solidification rapide des matériaux fondus conduit à des propriétés quise comparent de façon favorable à celles obtenues avec les techniques classiques d'élaboration et de mise en oeuvre. / As a new manufacturing technology, Selective laser melting (SLM) has a large potential in the manufacturing of complex parts with ultrafine microstructure.Selective laser melting has many significant advantages over traditional manufacturing methods but still faces a low availability of powder materials. With SLM, the part is firstly designed via 3D computer-aided design (CAD)), then built layer-by-layer with a high energy computer-controlled laser beam The work done in this study was therefore aiming at developing a new way to obtain alloys and composites directly from elemental powder mixtures with a large composition flexibility.Experimentally the choice was made of the aluminum-silicon system with several silicon contents (12, 18, 50 wt. %).Adding a static magnetic field was also considered as an additional way to control the microstructure. When parts are manufactured by SLM, laser power and scanning speed are the main parameters determining the density, microstructure, phase composition and mechanical properties. A systematic analysis of the role of these parameter on the manufacturing of Al - Si alloys by SLM from mixtures of powders was therefore conducted. Al - Si alloys with a very fine microstructure were thus obtained for several composition ranges corresponding to practical applications (lightweight structures, high wear resistance alloys, electronic packaging material, ...). The properties of the materials obtained in this way, according to the performed characterizations, compares favorably with those obtained via the conventional production technologies.