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Technical Paper

“Seizure-Delay” Method for Determining the Seizure Protection of EP Lubricants

IT does not yet seem to be recognized fully that it is the local temperature at the surface of contact and not the local specific pressure that chiefly determines the occurrence of seizure under extreme-pressure-lubrication conditions. This local temperature is the result of the temperature level of the parts lubricated, considered as a whole (“bulk” temperature) and of a superimposed instantaneous temperature rise (temperature “flash”) which is localized in the surface of contact. It appears typical for extreme-pressure-lubrication conditions, as met in gear practice, that the temperature flash is much higher than the bulk temperature. With existing conventional test methods for the determination of the protection against seizure afforded by EP lubricants, a considerable rise of the bulk temperature mostly occurs; as it cannot be controlled sufficiently; thus, leaving an unknown margin for the temperature flash, it renders impossible a reliable determination.
Technical Paper

“Rubber Coupling” at a 4×4 Transmition System

There are many different vibration sources in a car. Engine, gears, road roughness, impacts against the wheels cause vibration and sound that can decrease the parts and the car durability as well as affect drivability, safety and passengers and community comfort. In 4×4 cars, some extra vibration sources are the parts responsible for transmitting the torque and power to the rear wheels. Each of them has their own vibration modes, excited mostly by its imbalance or by the second order engine vibration. The engine vibration is a very well known phenomena and the rear driveshaft is designed not to have any vibration mode in the range of frequencies that the engine works or its second order. The imbalance of a driveshaft is also a design requirement. That means, the acceptable imbalance of the driveshaft is limited to a maximum value.
Technical Paper

“RoHS” Compliant Chrome - Free Conversion Coating for Aerospace Manufacturing

This paper presents, chemistry, test data and processing procedures on a non toxic and environmentally friendly chrome-free conversion coating alternative with the same level of adhesion and secondary corrosion resistance as that found in chrome containing conversion coating systems. Test data from military and independent sources will be presented on secondary coating adhesion, electrical conductivity, filiform and neutral salt-spray corrosion resistance as compared to chromate based systems .on magnesium, aluminum and zinc and their respective alloys. The European “RoSH” initiative will not allow for the presence of any hexavalent chromium on imported electrical components as of July first of 2006. Trivalent chromium based systems generate hexavalent chromium due to the oxidation of the trivalent chromium and as such will not be allowed.
Technical Paper

“Projection-by-Projection” Approach: A Spectral Method for Multiaxial Random Fatigue

This paper presents a fatigue criterion based on stress invariants for the frequency-based analysis of multiaxial random stresses. The criterion, named “Projection-by-Projection” (PbP) spectral method, is a frequency-based reformulation of its time-domain definition. In the time domain PbP method, a random stress path is first projected along the axes of a principal reference frame in the deviatoric space, thus defining a set of uniaxial random stress projections. In the frequency-domain approach, the damage of stress projections is estimated from the stress PSD matrix. Fatigue damage of the multiaxial stress is next calculated by summing up the fatigue damage of every stress projection. The criterion is calibrated on fatigue strength properties for axial and torsion loading. The calculated damage is shown to also depend on the relative ratio of hydrostatic to deviatoric stress components.
Technical Paper

“Insert and Fly” Using PCMCIA PC Cards in the Avionics Market

When looking into using PCMCIA PC Cards in the avionics market, three areas must be researched. The first is what are the applications and benefits of using the PC Cards while in flight, followed by the applications and benefits on the ground, and thirdly on how to make a PC Card that would stand up to the rugged avionics environment. PCMCIA PC Cards can be used in all aspects of flight. Three possible applications on the ground are; paperless documentation, modifications, flightline changes. Once airborne, PC Cards can be removed and a different functionality card can be inserted. One PC card socket can be used for many different functions during one flight. Some of the possible applications for PC Cards inflight are; flight plan changes, backup Line Replaceable Units (LRUs), and solid state data collection.
Technical Paper

“Evaluation of the Drift of vehicle Inspection/Maintenance Emission Analyzers in use- A California Case Study”

Quality assurance (QA) in motor vehicle emissions inspection/maintenance (I/M) programs is a continuing concern, especially in decentralized programs with hundreds or even thousands of licensed stations. The emissions analyzers used in such stations are an important focus of governmental QA efforts because of the central role of analyzers in determining which vehicles need to be repaired. Therefore, the In-use performance of I/M emission analyzers has a large impact on the quality of 1/M programs as a whole. This paper reports on the results of an investigation in California designed to determine in-use performance of emission analyzers in the field. The investigation was designed to evaluate both drift rates and the ability of analyzer systems with automatic gas calibration capability to correct analyzer responses outside of accepted tolerances.
Technical Paper

“Cromard” Thin Wall Steel Liners and Hard Chrome Plated Liners for High Production Gasoline and Diesel Engines

This paper, confined to the application of hard chrome plated liners to high-speed four-stroke diesel and gasoline engines, illustrates the increase in their popularity in the United Kingdom, and the advanced production methods which make this economically possible. The need for balanced engine life has long been apparent and is even more important today, the growth of motor transport having outstripped repair facilities. Iron bore life has been surpassed by improvement in the life of other component parts in the modern diesel engine. The provision of hard chrome plated liners can restore the balance. Further development and turbocharging of diesel engines has shown the need for a bore material capable of preventing scuffing and galling at elevated temperatures. Hard chrome has already proved itself in four-stroke engines under these conditions.
Technical Paper

the effect of Residual Stresses Induced by Strain-Peening upon Fatigue Strength

THE PURPOSE of this experiment was to determine the role of residual stresses in fatigue strength independent of other factors usually involved when residual stresses are introduced. It consisted of an investigation of the influence of residual stresses introduced by shotpeening on the fatigue strength of steel (Rockwell C hardness 48) in unidirectional bending. Residual stresses were varied by peening under various conditions of applied strain. This process introduced substantially the same amount and kind of surface cold working with residual stresses varying over a wide range of values. It was found that shotpeening of steel of this hardness is beneficial primarily because of the nature of the macro-residual-stresses introduced by the process. There is no gain attributable to “strain-hardening” for this material. An effort was made to explain the results on the basis of three failure criteria: distortion energy, maximum shear stress, and maximum stress.*
Technical Paper

Zn-Ni Plating as a Cadmium Alternative

In a 2-year program sponsored by SJAC, an aqueous electroplating process using alkaline Zn-Ni with trivalent chromium post treatment is under evaluation for high strength steel for aircraft application as an alternative to cadmium. Commercial Zn-15%Ni rack/barrel plating solutions are basis for plating aircraft parts or fasteners. Brightener was reduced from the original formula to form porous plating that enables bake-out of hydrogen to avoid hydrogen embrittlement condition. Properties of the deposit, such as appearance, adhesion, un-scribed corrosion resistance, and galvanic corrosion resistance in contact with Al alloy, were evaluated. Coefficient of friction was compared with Cd plating by torque-tension measurements. Evaluation of the plating for scribed corrosion resistance, primer adhesion, etc. will continue in FY2007.
Technical Paper

Zinc-Magnesium-Aluminium (ZM)-HDG-Coated Steel Sheet for Structural Parts to Outer Panels

Zinc-coatings with a substantial Magnesium content have been in use for over 30 years by now. Unlike the well-established Zn-Al-Mg coatings originating from Japan which have significant higher alloying contents applied mainly for building applications, this Zinc Magnesium Aluminum coating (ZM) is also specifically designed to meet the requirements of car manufacturers. The ZM coating introduced by voestalpine, corrender, is in the upper range of ZM-alloying compositions, which was set by VDA (German Association of the Automotive Industry) and SAE to be within 1.0 to 2.0 wt. % Mg and 1.0 to 3.0 wt. % Al. The properties of these “European” Zinc-Magnesium coatings are well comparable within this range. Compared to GI and GA ZM coatings exhibit significant advantages in the press shops with its excellent formability and reduced galling and powdering respectively which is a significant advantage for the forming of outer panels.