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Reflecting the need for field testing of bimetallic automotive body sheet; an extensive program was planned in 1974. Adhesive bonded and weld bonded panels (2036 aluminum and 5182 aluminum with 1010 steel) were prepared and exposed at atmospheric test sites at Pompano Beach, Florida; Phoenix, Arizona; Chicago, Illinois; and Richmond, Virginia. Exposures were made in 1975-76 and 1- and 2-yr removals and evaluations are reported in this paper. “In-plant” and “After-market” repaired aluminum panels were exposed at the same time. These results are reported here.

The interest in aluminum alloys and aluminum joining in the automotive industry has increased considerably over the past few years as a result of new fuel economy, air pollution and safety requirements. Aluminum is the best alternative to steel to make lighter and more fuel-efficient automobiles. Several aluminum alloys have been considered for body sheet components. The new Alcoa 6009-T4 and 6010-T4 alloys were developed and introduced in 1976 to increase the attractiveness of aluminum for body sheet components. These alloys have good formability in the as-received condition and superior strength and dent resistance in the aged (-T6) condition which can be achieved in paint bake cycles. These alloys are similar in composition and do not require scrap segregation. In addition, the 6009/6010 alloys provide improved welding characteristics through a combination of better metallurgical characteristics and lower and more uniform surface resistance.

The Friction Stir Welding FSW process, polymeric materials respond differently than metallic materials. In addition, the same tool design concept is not able to produce good surface quality with strong welds. Because the welding parameter is so important in this procedure the key The goal of this effort was to construct a novel welding tool that could produce reliable seams for all types of polymers, independent of their configurations, without the use of an additional heat source. The study initially concentrated on the development of the tool and the optimization of the welding parameters. Before arriving at the final tool design, which was able to produce more frictional heat and have superior surface polish, various tools were conceived, produced, and tested. Statistical methods were used to optimize the welding procedures, and numerous mechanical tests were carried out to determine the weld strength.

The successful integration of P/M into a large number of subassemblies can depend on the ability to join P/M components to each other and to wrought materials. Common methods of joining metal components, such as brazing and welding, can give unexpected results when applied to P/M. The purpose of this paper is to investigate the joining of P/M components of varying hardenability, density, and composition using friction welding, high speed pulse welding, gas tungsten arc welding, and brazing. The joints are evaluated using ultimate strength, microhardness, and microstructure. The results show that solid state process, such as high speed pulse welding and friction welding are applicable to all but the highest hardenability materials. Gas tungsten arc welding has less applicability due to crack formation upon cooling. Brazing is generally applicable with most P/M materials assuming a suitable filler metal is selected.

A comparison of standard methods of joining P/M structures, as well as new techniques. The porosity of a P/M part is no longer a problem when joining P/M to P/M or P/M to wrought. These joints will be as strong or stronger than the P/M material. The systems give the design engineer more flexibility.

The joining process of silicon nitride (S13N4) turbine rotor and steel metal shaft was investigated. The process consists of brazing procedures with multi-layer metallizing and complementary steps involving shrink fitting and non-destructive tests. In the course of the brazing steps, preliminary investigations using small specimens were conducted on the formation of a highly strengthened interface at high temperature and thermal stress reduction, and superior high temperature strength and heat cycle resistance were obtained. Rotary tests at high temperature were successfully completed using the rotor joined by this process.

Solid rods of dissimilar metals are easily welded by friction welding. This process is a solid-state process where no fumes or gases are released which is friendly to the environment. In advanced engineering practice, joining Titanium (Ti) alloy and stainless steel (SS) is very important due to poor bonding strength in direct joining. These materials are easily joined by an interlayer technique using materials like nickel, silver, niobium, aluminum, and copper. Special surface geometry techniques hold the interlayer materials between dissimilar metals in different forms like coating, foils, and solid metals. In this investigation, the finite element method is used for modeling the process, and the Johnson-cook equation was used to find the analysis of output values with the defined material properties. The heat generated is calculated and numerically compared and analyzed with experimental results. Observations such as metallography, hardness, and tensile test were studied.

Joining of a PdCr Strain Gage with a Hastelloy X carrier shim to Inconel by a rapid infrared processing technique has been investigated at 1150 °C using a nickel based brazing alloy AMS 4777, Ni-7Cr-3Fe-3.2B-4.5Si-.06C in wt%. The effects of the infrared joining parameters on the joint and base material microstructure, joint shear strength, and delamination tendency of the PdCr gage was investigated. Results show that the joint shear strength is as high as 503 MPa when processed at approximately 1150 °C for 120 seconds. Microstructural examinations of the joint with both an optical microscope and a scanning electron microscope indicate that good wetting exists between the brazing alloy with both the Hastelloy X and Inconel 718. And, the Hastelloy X and Inconel 718 exhibits no noticeable change in microstructure due to the rapid processing cycle of the infrared heating process while the stabilized PdCr wire gage shows little change in resistance.

The method of attachment and the effects of the joining method are of equal importance to the selection of materials. Exotic materials, sandwiches, composites, thin multilayered, and truss type configurations are presently being conceived, tested as simple beams and columns, and immediately converted into briefing charts Joining design problems arising from inadequate consideration of practical factors are shown. Examples are given ranging from the WW II aircraft (a collection of holes held together with fasteners) to the present day space vehicles'fastening system.

A joint system for a dual inlet muffler has been designed which allows the muffler system to be better aligned during assembly. The system uses a slip-fit joint coupled with a ball-and-flair joint. This combination decreases variations in manufacturing and assembly thus, improving tailpipe variability in the vehicle build. The slip-fit/ball-flair joint was compared to conventional inlet systems of flat flanges and flex-couplings. A Variable Simulation Analysis (VSA) audit, finite element analysis of the joint strengths, and variable cost study all showed advantages for the slip-fit/ball-flair system.

Environmental perception is a crucial subsystem in autonomous vehicles. In order to build safe and efficient traffic transportation, several researches have been proposed to build accurate, robust and real-time perception systems. Camera and LiDAR are widely equipped on autonomous self-driving cars and developed with many algorithms in recent years. The fusion system of camera and LiDAR provides state-of the-art methods for environmental perception due to the defects of single vehicular sensor. Extrinsic parameter calibration is able to align the coordinate systems of sensors and has been drawing enormous attention. However, differ from spatial alignment of two sensors’ data, joint calibration of multi-sensors (more than two sensors) should balance the degree of alignment between each two sensors.

The ACMA (Advanced Civil/Military Aircraft) is conceived as an advanced technology transport aircraft designed from the outset with the potential for fulfilling both the U.S. need for military strategic airlift and the worldwide need for commercial airfreight in the 1990s and beyond. The ACMA, initially called the C-XX, was first described in 1974, and is the subject of a Military Airlift Command Statement of Operational Need (SON) published in 1979. Evidence of the corresponding civil need for a large payload, long range cargo transport has been supplied by the NASA sponsored Cargo Logistics Airlift System Studies (CLASS). The recent preconceptual studies of the ACMA which examine both the technical and institutional issues affecting a joint program indicate that there are no significant obstacles to developing a single, basic configuration, or in administering such a venture.

The requirement for increased airlift capability is now documented in the Hq. Military Airlift Command Statement of Operational Need. Many studies were conducted to investigate the alternative solutions proposed to meet this need, both in terms of operational concepts and unconventional fuels and configuration. Preliminary results indicate that a joint Civil/Military transport aircraft of conventional configuration and fuel is the most cost effective means to satisfy the increased airlift need. Maximum utilization of advanced technology and government/industry cooperation will be required to achieve the economic incentives necessary to successfully accomplish this joint aircraft program.

This paper describes the development of joint design approach for aluminum space frame. The space frame consists of thin-walled closed extrusions joined by welding. A welded joint cannot be treated by the rigid joint assumption for the effect of the weld line. The continuous fillet parts are modelled as interface elements using detailed finite element model. The study presents the equivalent effective Young's modulus and the effective zone with equivalent modulus. The structural joint stiffnesses of several pillars are calculated by the present joint design method and examined by stiffness test. The effects of fillet size, wall thickness and pillar geometry are considered. The results provide a useful and general method to predict the stiffness of joints with various configurations, and practical guidelines to analyze the stiffness of aluminum space frame.

The need to substantially reduce the weight of automobiles to improve performance or meet CAFE requirements has led to an increased use of lightweight materials such as aluminum. To use aluminum efficiently in auto body structures, component and joint designs and joining methods are likely to differ from those traditionally used in steel bodies. With proper design, aluminum automotive frames can efficiently meet or exceed the performance requirements for stiffness, static strength, fatigue strength and crash performance. This paper presents some joint design concepts for aluminum frames and compares the performance of joining methods such as resistance spot welding (RSW), gas metal arc (GMA) welding, weld bonding, adhesive bonding, riveting and mechanical clinching for both unibody and spaceframe construction. Recommendations for preferred joining methods are also made based on the effect of design details on joint performance and assembly.

The USAF in conjunction with NASA and the Jet Propulsion Laboratory established the DoD/NASA joint program to competitively develop high power, lithium ion battery technology and to establish North American domestic sources for lithium ion batteries. The program was initiated in FY97 to meet DoD and NASA requirements not addressed by commercial battery developments. Four contracts were awarded for cylindrical and prismatic cell and battery systems development. Technical and program management advisory groups were established to coordinate program management and to verify and validate test results from individual contractors. Specific applications, contract deliverable items and the overall schedule are presented.

The challenge of tough fuel consumption reduction targets and near zero NOx emission standards can be met by optimization of the full range of engine design variables. Here these are explored through an engine simulation model and the application of an optimizing algorithm that can work in discontinuous data space. The combustion model has main features that include flame propagation, the effects of turbulence, chamber shape interaction and NOx formation. Two engine configurations are used to illustrate the application of the model and optimizer. Both allow the adoption of extra lean burn possible with LPG as fuel and EGR through an external route or cam phasing. In the first the compression ratio and cam profiles are fixed, in the second study they are also optimized.

Despite its wide use and many years of engineering research and development, most suspensions, particularly “The McPherson Suspension”, have not been investigated as truly three-dimensional mechanisms. In this paper the McPherson Suspension, which is modeled first as a three-dimensional guiding mechanism, is analyzed for the forces and moments at each of the joints with its continuous displacement pattern of the suspension, in three dimensional space. With the development and use of effective software such as “Nonlinear Simultaneous Equations Solver” and “Displacement Matrix Method” this paper, for the first time, presents an analysis of forces and moments of joints of rubber bushings to evaluate accurately the compliance effects.

Despite its wide use and many years of engineering research and development, most suspensions, particularly “The McPherson Suspension”, have not been investigated as truly three-dimensional mechanisms. In this paper the McPherson Suspension, which is modeled first as a three-dimensional guiding mechanism, is analyzed for the forces and moments at each of the joints with its continuous displacement pattern of the suspension, in three dimensional space. With the development and use of effective software such as “Nonlinear Simultaneous Equations Solver” and “Displacement Matrix Method” this paper, for the first time, presents an analysis of forces and moments of joints of rubber bushings to evaluate accurately the compliance effects.

Organizational interfaces generally bring with them engineering data exchange interfaces. Front end planning, standardization, and simplifications can mitigate cost and schedule risks associated with these interfaces. The proliferation of high speed personal computers (PCs) and associated technical software make them an inexpensive bridge between projects and organizations.