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Technical Paper

100 Hour Endurance Testing of a High Output Adiabatic Diesel Engine

An advanced low heat rejection engine concept has successfully completed a 100 hour endurance test. The combustion chamber components were insulated with thermal barrier coatings. The engine components included a titanium piston, titanium headface plate, titanium cylinder liner insert, M2 steel valve guides and monolithic zirconia valve seat inserts. The tribological system was composed of a ceramic chrome oxide coated cylinder liner, chrome carbide coated piston rings and an advanced polyolester class lubricant. The top piston compression ring Included a novel design feature to provide self-cleaning of ring groove lubricant deposits to prevent ring face scuffing. The prototype test engine demonstrated 52 percent reduction in radiator heat rejection with reduced intake air aftercooling and strategic forced oil cooling.
Technical Paper

47 Development of a Titanium Material by Utilizing Off-Grade Titanium Sponge

Titanium alloy for forging and pure titanium material for exhaust systems have been developed. The forging alloy will be applied to production of lightweight motorcycle frames and the pure titanium will be applied to improve engine performance. The materials have been made inexpensive by the use of off-grade sponge that includes many impurities for production of titanium ingot. Stable characteristics have been obtained by controlling oxygen equivalent after setting the volume of tolerable impurities by considering mechanical properties and production engineering. In spite of low-cost, the material provides the same design strength compared to conventional material, and enables parts production with existing equipment. A review of manufacturing and surface treatment processes indicated a reduction in the price of titanium parts produced with this new material.
Technical Paper

A Comparison of Root Module Designs Relative to Wheat Growth and Development: Defining the Requirements for a Space Based Plant Culture System

Wheat plants were grown at water potentials in the root zone of -0.4, -3.0, and -5.0 kPa in root modules with various porous membranes through which the nutrient solution was delivered. Root modules contained plants grown during 49 days on different types of porous membranes: ceramic porous tubes with diameters of 10 mm or 22 mm, a porous titanium plate, in a compartment with a porous ceramic tube in perlite and in a 2.5 cm layer of perlite which covered a porous titanium plate. Root modules containing perlite showed much higher dry mass plants in yield than plants in root modules without perlite. A drop in water potential resulted in growth inhibition in all of the modules, especially in the tests without perlite. Design characteristics of the modules significantly affected the root distribution volume. These results may provide additional information in the design of root modules for future space plant growth chambers.
Technical Paper

A Comparison of the Technical Properties of Arc Sprayed Versus Plasma Sprayed Nickel-5 Aluminum

Nickel-5 Aluminum (95 % Nickel-5 % Aluminum) is widely used in the aircraft engine industry. The excellent adhesive and cohesive strength of the coating, oxidation resistance and machinability make it an ideal material as both a bond coat for subsequent topcoats and as a build up material for dimensional restoration of worn or mismachined components. Plasma spraying has traditionally been the thermal spray process used to apply nickel aluminum, and the technical properties and performance characteristics are well documented. More recently, wire arc sprayed nickel aluminum is becoming widely used as an alternative to plasma spraying due to higher bond strengths, reproducibility, better machinability and more favorable economics. This paper presents the results of a testing program designed to compare the technical properties of arc sprayed versus plasma sprayed Nickel-5 Aluminum coatings.
Technical Paper

A Corrosion Inhibiting Coating for Structural Airframe Fasteners

Corrosion problems associated with using titanium fasteners to assemble aluminum airframe structures are reviewed. Data are presented describing the effectiveness of metallic platings and an aluminum filled organic based coating on fasteners to render the titanium-aluminum electrochemical couple inoperative. The aluminum enriched organic coating known as Hi-Kote 1 is shown to be more effective in minimizing corrosive attack on aluminum airframe structure in both saline and acidic environments. The effectiveness of Hi-Kote 1 in corrosion-fatigue tests of fastened aluminum structure is also reported.
Journal Article

A Coupled Eulerian Lagrangian Finite Element Model of Drilling Titanium and Aluminium Alloys

Despite the increasing use of carbon fibre reinforced plastic (CFRP) composites, titanium and aluminium alloys still constitute a significant proportion of modern civil aircraft structures, which are primarily assembled via mechanical joining techniques. Drilling of fastening holes is therefore a critical operation, which has to meet stringent geometric tolerance and integrity criteria. The paper details the development of a three-dimensional (3D) finite element (FE) model for drilling aerospace grade aluminium (AA7010-T7451 and AA2024-T351) and titanium (Ti-6Al-4V) alloys. The FE simulation employed a Coupled Eulerian Lagrangian (CEL) technique. The cutting tool was modelled according to a Lagrangian formulation in which the mesh follows the material displacement while the workpiece was represented by a non-translating and material deformation independent Eulerian mesh.
Journal Article

A Global Improvement in Drilling and Countersinking of Multi-Material Stacks with Vibration Assisted Drilling

Over the last few years, many aircraft production lines have seen their production rate increase. In some cases, to avoid bottlenecks in the assembly lines, the productivity of processes needs to be improved while keeping existing machine-tools. In this context, the case of drilling machine-tools tends to require particular attention, especially when multi-material parts are drilled. In such instances, the Vibration Assisted Drilling (VAD) process can be a way to improve productivity and reliability while keeping quality standards. This article presents a case of a drilling/countersinking process for stainless steel and titanium stack parts. Firstly, the article assesses the feasibility and benefits of using Vibration Assisted Drilling and Countersinking with the current cutting-tools. Secondly, it studies the consequences of introducing a new tool holder in the process, which combines the V.A.D. function, a new declutching function and the ability to control countersink depth.
Technical Paper

A Life-Cycle-Based Environmental Evaluation: Materials in New Generation Vehicles

This project team conducted a life-cycle-based environmental evaluation of new, lightweight materials (e.g., titanium, magnesium) used in two concept 3XVs -- i.e., automobiles that are three times more fuel efficient than today's automobiles -- that are being designed and developed in support of the Partnership for a New Generation of Vehicles (PNGV) program. The two concept vehicles studied were the DaimlerChrysler ESX2 and the Ford P2000. Data for this research were drawn from a wide range of sources, including: the two automobile manufacturers; automobile industry reports; government and proprietary databases; past life-cycle assessments; interviews with industry experts; and models.
Technical Paper

A New Approach to Titanium for Truck Suspension Springs

The titanium alloy system offers a range of properties conducive to weight/space savings. These properties include high strength, low elastic modulus and low density, which uniquely suit them for spring applications. By utilizing titanium in various spring designs, suspension engineers can save up to 60% of the weight and 20-30% of the space for a comparable steel spring. The primary impediment to widespread titanium part production and use in the past was cost. A new low cost titanium alloy system designed specifically for suspension and drive train application has been tested and proved to limit this cost problem. Working with titanium in their suspension designs, engineers will save significant weight/space over comparable steel and aluminum components.
Technical Paper

A New Technique for Testing Dynamic Tensile Behavior of Metals at Elevated Temperatures

A high-temperature tensile impact experimental technique, based on a rapid-contact heating method, is developed to test specimen at temperatures up to 1073K. High-strain-rate tensile responses of commercially pure titanium at elevated temperature are investigated. The testing results show that the yield stress and ultimate tensile stress all decrease with increasing temperature, while the fracture strain decreases with increasing temperature at the temperature range 25 °C350 °C.
Technical Paper

A Novel Concept of Power Transmission Gear Design

Conventional gear designs are characterized by the meshing teeth which have to accommodate bending loads with a high dynamic load content, together with high contact stresses under a reciprocal sliding. Accordingly, special materials with sophisticated heat treatments, and high fabrication accuracy are required for heavy-duty gears, such as being used in off-road vehicle transmissions The paper describes a novel concept for designing power transmission gears, which eliminates physical sliding between meshing profiles and separates bending and contact loading of the teeth. Geometrical sliding is accommodated by internal shear deformation in specially designed rubber-metal laminates, thus allowing materials with high bulk strength but poor contact properties (aluminum, titanium, fiber-reinforced composites, etc.) to be used for heavy-duty gears.
Technical Paper

A Study into the Potential Use of Photocatalysis for Atmosphere Treatment in Submarines

Nuclear submarines may remain at sea submerged for weeks or months at a time and a range of equipment is provided aboard to purify and re-vitalise the air in order to maintain a viable atmosphere for the crew to breathe over extended periods. Activated carbon beds are used to remove ppm-level organic contaminants that build up in the atmosphere from, for example, lubricants and the outgassing of materials of construction. These carbon beds require frequent replacement and present a substantial logistic demand. The beds also constitute an increased fire hazard as the amount of adsorbed material builds up. Photocatalysis is a process whereby a semiconductor catalyst material, typically titanium dioxide (TiO2), is irradiated in air with ultraviolet (UV) light. This produces high-energy hydroxyl radicals that are capable of completely oxidising a range of molecules to simple, relatively non-toxic, species. For instance, hydrocarbons are generally oxidised to water and carbon dioxide.
Technical Paper

A Systematic Procedure for Integrating Titanium Alloys as a Lightweight Automotive Material Alternative

For incorporating titanium components onto a vehicle in place of existing iron/steel components, there is a need for a methodical procedure to ensure successful and efficient integration. This involves a refinement over standard lightweight engineering procedures. In this paper, a suitable procedure is developed for replacing a structural component with titanium and the method realized. Design and manufacturing issues associated with integrating titanium are identified and addressed. The importance of justifying component replacement in terms of life-cycle costs rather than purely by the manufacturing cost alone is also emphasized.
Technical Paper

A Thermo-Resistive Flow Sensor for Injection Rate Measurements

In this study, a micromachined hot film anemometer, placed on a pressure stable LTCC substrate, is presented to measure the different injection quantities, needed in modern direct injection (DI) system for optimum performance. A bi-layer of Titanium (Ti) and Platinum (Pt) as advanced metallization system for the thin film resistors is used due to a lower resistivity and a higher temperature coefficient of resistance (TCR) compared to Molybdenum (Mo), which was taken for the first prototypes. Especially the increase in TCR is recommended for thermal mass flow sensors, as the resulting signal height is linearly related to this material parameter. Therefore, the new technology steps, to fabricate the sensor elements, are given in the paper. FEM simulations on the temperature distribution around the hot film anemometers in the injection nozzle reveal a minimum distance, where the temperature is increased compared to the ambient, of about 30 μm at a injection pressure of 20 MPa.
Technical Paper

A Ti/Pt Hot Film Anemometer for CR-Injection Systems

By e-beam evaporating a thin film resistor, consisting of a Titanium (≈10nm)/Platinum (≈100nm) bi-layer, on a LTCC (Low Temperature Cofired Ceramic) substrate, a robust and fast responding thermal mass flow sensor is developed. Due to the integration of the latter into the nozzle of a Common Rail (CR) injection system, important parameters, as the injection rate as well as the begin/end of the injection pulse, can be determined with high accuracy. By a closed-loop control of the magnetic or piezo-electric driven valve, a smooth combustion process with lower NOx emission values could be achieved. This present paper mainly focuses on analytical calculations to determine the velocity and temperature sensitivity of the thermal mass flow sensors in the constant-current (CC) mode.
Technical Paper

A breakthrough in handheld Smart Drilling Units : Material detection with advanced electrical drilling

The quality requirement for drilling operation in aerospace industry associated to the different material layers of the recent aircraft design is one of the most challenging issues for manufacturing engineers who want to design system for one-shot drilling operation. We have developed and validated in production a handheld electrical tool which is able to accurately monitor the drilling parameter and to adjust the drilling conditions to specific material in the stack-up. This “Smart Driller” achieves quality and performances equivalent to those obtained by the most advanced heavy automated drilling systems at a small portion of weight and cost.