Grey cast iron alloys for brake drum and brake disc applications are being developed with niobium additions and a range of equivalent carbon for commercial, passenger vehicle, and performance applications. The benefit of niobium in cast iron is based on the contribution of strength by matrix refinement for a given carbon equivalence that may permit the direct improvement of wear improvement or allow for an increase in carbon equivalence for a given strength. Proper carbon equivalency and pearlite stabilization contribute to an improved pearlite structure with an optimized distribution of graphite. These structures, when refined with niobium, demonstrate increased service life and reduced wear relative to their niobium-free equivalents as measured by lab dynamometer testing and by on-vehicle testing in passenger bus fleets.
Graphite plays a crucial role in friction materials, since it has good thermal conductivity, lubricity and act as a friction modifier. The right type, amount, shape, and size of the particles control the performance of the brake-pads. The theme of the study was investigating the influence of size of graphite particles (having all other specifications identical) on performance properties of brake-pads containing graphite particles in the average size of 60 �m, 120 �m, 200 �m and 400 �m. Physical, mechanical and chemical characterization of the developed brake-pads was done. The tribological performance was studied using a full- scale inertia brake dynamometer following a Japanese automobile testing standard (JASO C406). Tribo-performance in terms of fade resistance, friction stability and wear resistance were observed best for smaller graphite particles. It was concluded that smaller size serves best for achieving best performance properties barring compressibility.
Friction interaction between brake materials see a rise in temperatures of over 1000 oC contributing to thermal fade of brakes and deterioration/cracking of rotors. Various microstructural features like alloying, graphite morphology and size, morphology and contents of pearlite and ferrite could influence the thermal properties and related friction performance of the brake materials. Even more relevant impact on thermal properties of rotors can be expected after their coating by ceramics. The primary purpose of this research is to identify the impact of microstructure on thermal diffusivity of a commercially available ASTM A48 Class 30 gray cast iron brake rotor and an original equipment manufacturer (OEM) of Ford F150 combined with effects of ceramic coatings. Thermal diffusivity is a relevant property controlling the speed at which is heat dissipated from friction surfaces.
Regenerative braking in conjunction with friction braking represents one of the most common braking strategies employed in electric and hybrid vehicles. The considerably different role of the friction brake in these ?blended scenarios?, when compared with braking solely by friction brakes, creates potential for development of new advanced and sustainable brake materials and brake designs. Fiber reinforcements used in friction brake material play an important role in improving strength, stability, and frictional properties [1, 2, 3]. This study concentrated on the development of a new generation of lightweight, ?quiet? and environmentally sustainable brake pad materials to be used with coated cast iron rotors in vehicles with regenerative braking.
Regenerative braking is an important system of an electric/hybrid vehicle as it enables to recover the considerable part of its kinetic energy. Since the braking torque demand could often be higher than the torque provided by the electric motor, a ??blended?? approach of friction and regenerative braking is used . This provides an opportunity for development of advanced new designs of regenerative brakes and a new series of advanced lightweight, low wear, high strength, corrosion mitigating and sustainable friction materials. This study focuses on the performance of a newly patented polyimide matrix composites reinforced with Kevlar fabric and further modified with carbon nanoadditives. These alternative friction materials are very light and are free of not only asbestos and copper, but also of other environmentally challenging constituents potentially used in friction materials.
The aim of this paper is to analyse the quantitative impact of fuel sulphur content on particulate oxidation catalyst (POC) functionality, focusing on soot emission reduction and the ability to regenerate. Studies were conducted on fuels containing three different levels of sulphur, covering the range of 6 to 340 parts per million, for a light-duty application. The data presented in this paper provide further insights into the specific issues associated with usage of a POC with fuels of higher sulphur content. A 48-hour loading phase was performed for each fuel, during which filter smoke number, temperature and back-pressure were all observed to vary depending on the fuel sulphur level. The Fuel Sulphur Content (FSC) affected also soot particle size distributions (particle number and size) so that with FSC 6 ppm the soot particle concentration was lower than with FSC 65 and 340, both upstream and downstream of the POC.
TERBAN® hydrogenated nitrile rubber (HNBR) is a specialty elastomer used in demanding engineering applications such as the automotive, heavy duty, and industrial markets. It has excellent combination of heat, oil and abrasion resistance in addition to its high mechanical strength, very good dynamic and sealing properties. This paper will present data on aging HNBR for five thousand hours in an aggressive and un-stabilized B30A biodiesel fuel blend (70% ULSD, 30% SME, and an aggressive additive package) and explore the effect of HNBR polymer properties and vulcanizate composition on the performance in such fuel blends. Presenter Victor Nasreddine
Exatec� PC glazing technology team, has developed advanced weathering and abrasion resistant coatings technology that can be applied to protect polycarbonate. It is of particular interest to quantify and understand the factors that determine the surface abrasion performance of coated PC in rear window and backlight applications that have a wiper system. In the present study we describe Exatec's lab scale wiper testing equipment and test protocols. We also describe adaptation of optical imaging system to measure contrast and nano-profiling using nano-indenter, as post wiper surface characterization methods. These methods are more sensitive to fine scratches on glazing surface than standard haze measurement and mechanical profilometry. Three coating systems were investigated; Siloxane wetcoat (A), Siloxane wetcoat (B), and Siloxane wetcoat (B) plus plasma coat (Exatec� E900 coating). The performance comparisons were made using all these surface characterization methods.
For internal combustion engines and industrial machinery, it is well recognized that the most cost-effective way of reducing energy consumption and extending service life is through lubricant development. This presentation summarizes our recent R&D achievements on developing a new class of candidate lubricants or oil additives ionic liquids (ILs). Features of ILs making them attractive for lubrication include high thermal stability, low vapor pressure, non-flammability, and intrinsic high polarity. When used as neat lubricants, selected ILs demonstrated lower friction under elastohydrodynamic lubrication and less wear at boundary lubrication benchmarked against fully-formulated engine oils in our bench tests. More encouragingly, a group of non-corrosive, oil-miscible ILs has recently been developed and demonstrated multiple additive functionalities including anti-wear and friction modifier when blended into hydrocarbon base oils.
The increasing complexity of aerospace products and programs and the growing competitive pressure is facilitating the aggregation of small, medium and large enterprises of certain geographical regions into more integrated and collaborative entities (clusters). Clusters are by their same nature formed by heterogeneous companies, with huge differences not only in size but also for their core competences: such a diversity is a strength of the cluster, but it also increases its complexity. The purpose of this paper is to describe a benchmarking methodology that can be adopted to assess the performances of companies belonging to a cluster from different perspectives: economics and financials, competitive differentiators, specific know how, business strategies, production and logistic effectiveness, quality of core and supporting processes.
Micro-pitting is a fatigue effect that occurs in geared transmission systems due to high contact stress, and monitoring its progression is vital to prevent the eventual failure of the tooth flank. Parameter signature analysis has been successfully used to monitor bending fatigue failure and advanced phases of gear surface fatigue failure such as macro-pitting and scuffing. However, due to modern improvements in steel production the main cause of gear contact fatigue failure can be attributed to surface micro-pitting rather than sub-surface phenomena. Responding to the consequent demand to detect and monitor the progression of micro-pitting, this study experimentally evaluated the development of micro-pitting in spur gears using vibration and oil debris analysis. The paper presents the development of an online health monitoring system for use with back-to-back gear test rigs.
With the growing use of carbon fiber composite structure in Aircraft Manufacturing, the challenge of drilling carbon fiber stacked with Titanium has become a focus point. Due to the abrasive nature of the carbon fiber (CF), cutting tool life is relatively short when drilling carbon fiber stalked with Titanium. A common drill wear indicator is exit burr formation in the Titanium. As drilling tools wear due to the abrasive nature of the CF, the exit burr in the in the Titanium increases. This study seeks to understand the factors that lead to tool wear and exit burr formation. A correlation may be made relating drilling thrust forces with exit burr formation. Different cutting tools geometries and materials are studied using a high speed camera to attempt to understand the factors influencing exit burr formation. Findings are optimized and tested. Decreasing exit burr in the drilling of CF and Titanium may increase tool life thereby reducing tool costs to airframe manufacturers.
With the increased usage of Carbon Fiber Reinforced Plastics (CFRP) in the aircraft industry, there has been increased pressure to improve cutting tool life. Tungsten carbide tools were the first to be applied to CFRP materials. Poly Crystalline Diamond (PCD) tools also became an acceptable material to be used as a cutting tool material. In recent years, Chemical Vapor Deposition (CVD) diamond tools have become more popular as a cutting tool material for CFRP. This study compares these possible cutting tool materials in the drilling of CFRP. Wear is measured as well as hole quality. Life is determined by common industry standards with regard to fiber break out in a common CFRP material. An economic analysis is conducted in order to determine cost per hole. Presenter Christophe Petit
The foundation of many production aircraft assembly facilities is a more dynamic and unpredictable quantity than we would sometimes care to admit. Any tooling structures constructed on these floors, no matter how thoroughly analyzed or well understood, are at the mercy of settling and shifting concrete, which can cause very lengthy and costly periodic re-certification and adjustment procedures. It is with this in mind, then, that we explore the design possibilities for one such structure to be built in Belfast, North Ireland for the assembly of the Shorts C-Series aircraft wings. We evaluate the peak floor pressure, weight, gravity deflection, drilling deflection, and thermal deflection of four promising structures and discover that carefully designed pivot points and tension members can offer significant benefits in some areas.