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The efficient use of materials to absorb kinetic energy in automobile components subjected to impact loads has been receiving increased attention due to the reduced crush space on smaller vehicles. Substitution of lightweight materials into primary structural components has further accelerated the need to characterize the impact performance of a variety of new materials. This paper summarizes the results of an experimental program that was undertaken to investigate the impact performance of composite front-end components of a composite space frame based on a targa-top body configuration. Various front lower body rails designed with Kevlar-fiber composite materials were evaluated for energy absorption using static crush tests. A dynamic sled test of a Kevlar front substructure was completed and compared to a similar test of a mild steel front substructure.

Continuous-fiber composite materials are currently being evaluated as replacement materials for conventional steel alloys for primary load-carrying members of automotive structures. The objective of this study was to design and fabricate a composite space frame based on a targa-top body configuration. The present paper summarizes the overall structural design, fabrication, and vibrational response of the space frame. Initial structural optimization studies based on elastic load conditions were completed for the structure. Subsequent studies were directed toward redesigning the fiber orientation and thickness of the space frame beams to account for fabrication limitations and frontal impact loads. The frequency response of the composite structure was also determined computationally and experimentally and compared to the response of an optimized mild steel space frame.

Principals of operation and calibration of an instrument for measuring the local current density in an electroplating operation are presented. The use of the instrument to predict and control deposit thickness is explained.

Causes of chromium cracks and operating conditions which minimize visible cracked hard chromium plating have been identified as a result of a literature study and published data study. Elimination of visible chicken wire cracking in chromium plating production has been obtained by reducing the chromic acid to sulfate ratio and current density in one case study. Analysis of data in the study indicates consistency in ways of reducing cracks. An experimental design consisting of chromic acid to sulfate ratio, current density and temperature is proposed to verify these findings.

This system is designed to recover nickel and chrome, oxidize cyanide with PHOTOZONE activated oxygen, precipitate the residual metals and remove organic contaminants from the discharge to recycle water for reuse in the plating facility. The system is designed to treat concentrated and dilute waste water at a flow rate of 140 gallons per minute. The total volume of spent concentrated plating solutions is 127,000 gallons per year.

Environmental regulations are tightening worker exposure limits and disposal options for airlines who chemically strip and repaint their fleets. An alternative is to operate a polished aluminum aircraft fleet. The authors present an explanation of the grades of alclad aluminum fuselage skins used by commercial aircraft manufacturers and offer instructions on how to polish the unpainted alclad aluminum in order to operate the aircraft in the polished look. All fuselages on aircraft built by Boeing, Douglas, Lockheed, and the new EMBRAER Brasilia, were assembled using premium grade polished alclad aluminum. As a result, painted versions of aircraft built by the airframers have the capability to be stripped, polished and put in service as a polished aluminum aircraft.

Many aerospace components undergo a finishing process during their manufacture. Such finishing processes include chromium, nickel, zinc and cadmium plating on steels; anodize on aluminum alloys; and various coatings on titanium and nickel base alloys. Certain of these finishing processes result in loss of fatigue strength of the part in question. Loss of fatigue strength caused by chromium and nickel plating amounting to 60% has been measured. Shot peening is frequently used on fatigue critical parts to regain fatigue properties which may have been lost due to a particular finishing operation. Shot peening is a process which bombards the surface of a part with small spherical balls. The cold working effect of the peening balls leaves the surface of the part in a state of residual compressive stress. The beneficial compressive stresses induced by shot peening are effective in increasing fatigue properties of the component.

Determining residual stresses and detecting material defects through coatings is difficult with conventional testing techniques. X-ray diffraction can be used for residual stress determination on bare surfaces of a variety of materials, but fails to give any indication of stress in the underlaying metal through coatings. Nital etching cannot be used to detect grinding burns unless coating is removed. To overcome these difficulties, magnetic Barkhausen noise technique was used to study the feasibility of determining stresses and detecting grinding burns and heat treat defects through chrome plating. Test results suggest that the sensitivity of Barkhausen noise technique to defects and residual stresses through chrome is excellent up to plating thicknesses of 0.012 in. (0.3 mm). This technique can replace the presently used procedures to determine stress and to detect material defects through coatings.

A metallic matrix composite coating has been developed that imparts unique surface properties to a wide range of metallic substrates. The coating, based upon conventional electroless nickel technology, incorporates sub-micron particles of PTFE distributed uniformly throughout the coating thickness. The presence of the PTFE provides a continuous reservoir of lubricating particles giving a low friction surface that is accurate over the most complex components and that has many potential aerospace applications.

Coatings continue to be used on steel compressor components to maximize component life and compressor efficiency. Aluminum-ceramic coatings have been used on steel compressor components for a quarter of a century. During this time, coating application processes have been continually refined for improved performance. These processes are reviewed and a new process included - SermeTel Process 5380 DP. In this process, both coating material and process changes are made to produce finished coatings having improved surface finish, corrosion resistance and erosion properties. Test data is presented for comparison with earlier coating systems. For over twenty-five years, metallic-ceramic coatings have been successfully used on steel components of turbine engines to combat corrosion and erosion. The basic coating of this type, SermeTel W®, continues to be used in a variety of applications and is a base line from which new and improved coating systems can be compared.

A new system is presented for analysis and control of the chemistry of a metal finishing line. Parameters such as metals, acids, bases and pH are measured, statistically evaluated, and replenished. Results are viewed on a CRT screen, both current and historical, and output is provided in the form of graphs, tables, printed instructions and/or relay alarms. Examples are presented of parameters measured on a metal finishing line. THE TODD AUTOMATED CHEMICAL CONTROL SYSTEM took seven years to develop1. During that time, analysis of the critical parameters of seven processes were automated. The automation began with the electroless nickel plating process and was followed by titanium chemical milling, alkaline cleaning, chromated and non-chromated aluminum deoxidizing, chromic acid anodizing, and aluminum conversion coating. Replenishment was also implemented on two of the processes.

Air-Blasting with angular plastic blast media promises to be an effective and more environmentally secure method of removing paint and contaminants from aircraft for inspection and repainting purposes than conventional chemical treatments. Laboratory testing can be useful for determining optimum media sizes, and comparing different media for speed of paint removal and media breakdown. This paper explains the details of one test program, including a means for determining relative residual stresses imposed by plastic blasting. A discussion is also included on the effect of contaminants in the media on residual stress development.

It has been demonstrated in practice that inadequate training and/or process requirements have produced conflicting results. The purpose of this paper is to outline an acceptable training program in use by commercial airlines and the military. It may not be the only program in use, but it should be representative of what is required to enable plastic media blast (PMB) to become a viable process for commercial aviation processing as well as military or other industry applications. In addition attempts are made to document in bibliographical sequence test data supporting plastic media blast process applications. The objective again is to produce data supporting the viability of plastic media blast processing. As well as data already existing, we have included data currently being collected that may or may not support plastic media blast processing.

LASC-GEORGIA operates a large aircraft assembly plant located in Marietta, Georgia. This facility is owned by the U. S. Government and is known as Air Force Plant No. 6. As a part of the assembly operation, various metallic structures have metal finishes applied to them. Some of these parts are plated. A large portion of the parts are aluminum and may receive anodize or conversion coating finishes. Both the plating and aluminum finishing operations generate waste water that must be treated to meet National Pollution Discharge Elimination System (NPDES) discharge limits.

Project successfully produces data supporting generic nature of diffused aluminide coatings for gas turbine hot section components. The Department of Defense will prepare military specifications for use in competitive procurement of such coatings. The second objective of the project, to develop a low cost, generic coating procedure indicates cost savings of 50 to 80% and is basis for DoD process specification. Paper includes arguments and supporting data. A unique aspect of the project is that it was funded by commercial interests in lieu of the taxpayers.

Electrochemical metallizing (ECM) has been widely used in aircraft maintenance and OEM applications, but is far from reaching it's potential. Although ECM has been around for more than twenty years, it still represents a small part of metal finishing as a whole, thus making information describing the process not readily available. Most of the problems experienced with the process, aside from solution contamination, stem from improper tooling design, and will be the focus of this paper. Tooling and other areas covered will be as follows: 1 Anode design: choosing proper anode design for the job. 2 Flow-thru anodes: for more efficient distribution of electrolytes. 3 Precision build-ups: plating to size. 4 Solution and anode cooling: to prevent over-heating of solutions at the anode/work-piece interface and the effects on the deposit. 5 Masking techniques: how to make the tape work for you by reducing high and low current density problems. 6 Heavy build-up: depositing .050″ or more.

Magnesium alloys axe widely specified for aero-engine lubrication system casings because of their inherent lightweight. Advances in engine design and performance have increased lubricant temperatures to the point that magnesium corrosion can occur due to reaction with the hot oil. Work, carried out under Ministry of Defence contract has shown that Dow 17 anodic pretreatment of magnesium provided superior protection against hot lubricant attack compared to HAE anodic and chromate conversion coatings. Sealing the Dow 17 film with suitable epoxy or phenolic resins provided protection up to 200°C. Protection up to 225°C was obtained using a polyimide resin as the sealer.

A freeze crystallization process is being demonstrated for treating a wide variety of wastes generated in the plating and other industrial shops at the Norfolk, VA Naval Aviation Depot (NAD). As envisioned the freeze process will treat various rinses, plating baths, and cleaning solutions for recycle at the NAD, greatly reducing and even eliminating discharges to the industrial waste treatment plant. The manner in which the freeze process will be incorporated to do this includes: remove water with sufficient purity for recycle as rinse water and in bath makeup; concentrate the chemicals in rinse waters for recycle to plating baths; concentrate pickling wastes to recycle the concentrated acid while precipitating the dissolved metals for removal as innocuous sludge; concentrate paint strippers and solvents in rinses and other contaminated waters, separating useful organics from residual aqueous concentrates.

Many factors affect the susceptibility of steel to hydrogen-induced delayed brittle failure. The most important factor is the strength level of the specific steel alloy. Other factors are the applied load and hydrogen control. The susceptibility of high-strength steels to this type of failure can be determined with a sustained load test using notched round-bar tensile specimens or Douglas Aircraft Company stress rings. This paper describes the Douglas method of embrittle­ment testing(ASTM F519, Type 2a) for plating processes and contains information on how the stress rings were used to rate the relative embrittling tendencies of various plating processes. Stress rings and four different-sized loading bars were used to determine the susceptibility of electrolytic tank plating processes (cadmium, chromium and sulfamate nickel) and electrolytic brush plating processes (cadmium and sulfamate nickel) to hydrogen embrittlement under sustained load.

HOTOL is intended to provide a low cost means of delivering payloads to low earth orbit. The vehicle is thus designed for unmanned and largely-autonomous operations with very limited contact with a ground station. This paper outlines the Command and Control Systems studies undertaken to date and proposed for future phases.