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Viewing 1 to 30 of 189359
2012-06-13
Technical Paper
2012-01-1537
In industrial automotive transmissions, several noises can't be avoided such as gear rattle and gear whine noises. Indeed they result from the choice of gear technology. They just can be reduced by an appropriate design. It is widely acknowledged that gear whine noise is mainly due to transmission error, which depends on many parameters such as driveshaft deflection, gear stiffness and operating torque. All these parameters are not necessarily well-known, which may sometimes result in the choice of a gear geometry that doesn't minimize transmission error. That can lead to customer claims once the vehicle is manufactured. To cope with whine noise customer claims, we investigated a statistical gear optimization method. The principle is to use whine measurement data base on benches to find the best geometry against whine noise after a statistical treatment. The main advantage is that it is not necessary to know precisely all the parameters involved in whine noise.
1996-04-01
Technical Paper
91A092
B. Atzori, P. Lazzarin, S. Palma
A data bank developed to give a concrete help to the designer concerned with fatigue-prone structures made of composite materials is described. The data bank not only collects the available results of fatigue tests on these materials, but also makes easy their statistical analysis and comparison for design purposes. It is then believed to constitute also an useful research instrument for the development of design rules for well defined classes of composite materials.
1996-04-01
Technical Paper
91A088
Colin Austin
The article emphasizes the effect of flow on dimensional stability, mechanical properties and surface finish, and the close coupling of dimensional stability and mechanical properties. Warpage is the result of the balance between the structural stiffness of the part and the stress pattern resulting in variation in shrinkage due to area shrinkage, orientation, and thermal effects. The practical solution to warpage depends on the use of software to isolate the basic causes of warping which then leads to a logical solution procedure.
1996-04-01
Technical Paper
91A128
M. S. Wechsler, J. H. Van Gerpen
Shape memory materials undergo temperature-induced martensitic phase transformations that involve reversible dimensional changes. In performing these changes in shape, the shape-memory material is able to do work against external constraints, and this is the basis for shape-memory low-temperature heat engines. The transformation temperatures on heating and cooling are often not very different (little hysteresis) and are well defined and reproducible. Furthermore, these temperatures can be adjusted by varying the composition of the shape memory alloy. Internal combustion engines dissipate approximately two-thirds of the fuel energy as heat to the exhaust and coolant systems. A low-temperature heat engine could convert a fraction of this heat energy to useful work. This paper discusses the conceptual basis for the application of shape memory heat engines to internal combustion engine powered vehicles. Metallurgical and thermodynamic factors are discussed, as well as engine efficiency.
1996-04-01
Technical Paper
91A103
Dieter Stoeckel, Tom Borden
As a result of a phase transformation, shape memory alloys can change their shape when the temperature changes. This unusual effect can be utilized in actuation and fastening components for automotive applications. Springs made from Ni-Ti shape memory alloys change their rate in a predetermined temperature range due to a significant change in the elastic modules of the material. They can be used as sensor-actuators in pressures control valves or oil cooler by-pass valves in automatic transmissions or to compensate for oil viscosity changes in shock absorbers or thermal expansion of dissimilar materials in gear boxes. If the recovery is constrained, i.e., shape memory element is physically prevented from returning into its original shape, a potentially high stress is generated. This effect is used in fastener rings. Fasteners made from Ni-Ti alloys provide high reliability and easy installation for braid terminations, locating of shaft mounted components, connectors and hose clamps.
1996-04-01
Technical Paper
91A101
Antonio Cossolo
As a result of the rapid expansion of liquid molding in closed mold, fiberglass mat performers have rapidly changed in order to meet the high production requirements. The reasons for this interest in RTM and SRIM can be found in the considerable benefits offered by this technology which include: 1) ability to produce very large parts (weights up to 70 kg are currently being prototyped); 2) continuous and homogeneous reinforcement or even predetermined distribution of the reinforcement in the mold; 3) the ability to produce structures using cores of various types; and 4) the ability to use large inserts, even if they are metallic. The creation and development of this technology has been possible thanks to the introduction of very low viscosity reactive polymers. These materials permits very fast impregnation of the reinforcement in the closed model, thereby decreasing the cure time and the overall cycle time.
1996-04-01
Technical Paper
91A107
C. Olagnon, G. Fantozzi
Ceramic composite materials have been intensively studied during the last years. Particles and whisker reinforcement have shown the simultaneous advantage to allow the preparation of composite materials by conventional processing and to lead, when under optimum conditions, to dramatic toughening and strengthening. Since wear resistance of brittle material have been shown to be related to both hardness and toughness, composite materials with improved were resistance have been developed for cutting tools or bearing applications. However the mechanism responsible for toughening is of major important for wear resistance effectiveness. We have therefore reviewed the main mechanisms before presenting some examples of composites materials for wear resistance applications.
1996-04-01
Technical Paper
91A096
B. Atzori, P. Lazzarin, S. Segato, E. Rosseto
The paper summarizes the results of an experimental and numerical study performed on the rear door of a car of large production. It was carried out with a DMC ("dough molding compound") plastic material with short glass fibers. This technology makes strong the link between the production process and the mechanical properties of the component. Such properties really vary according to the fibers orientation, the distance from the injection points and the geometrical complexity of the different regions of the molded component. In some regions the fibers orientation is well defined, in others the orientation can be expressed only in average tendency terms, with a large scatter band. It is natural to think that the material modifies its behavior from region to region, showing marked orthotropic properties or, on the contrary, a compensation isotropic trend.
1996-04-01
Technical Paper
91A095
A. Antoniazzi, F. Berti, C. Fernandes, S. Grimaldi
A procedure adopted to verify and update the finite elements model of an electric powered car-body manufactured from composite materials is described. Experimental results, obtained from modal testing of the prototype, are used in order to identify and correct discrepancies in the FE model. The availability of a highly reliable FE model allows to simulate structural modifications by computer, optimizing the use of composites and reducing in the same time at minimum prototypes construction. The approach followed suggests a possible remarkable reduction in product development costs and duration. The work has been performed within a larger program for the development of thermoplastic composite materials, with particular attention to transportation market.
1996-04-01
Technical Paper
91A099
S. Raciti, F. Turris, F. Policelli
The utilization of the pultrusion process for the manufacturing of components and structures for the transportation industry is discussed. Both the characteristics and capabilities of the process and the properties of pultruded composites are reviewed. The most important characteristics of this process is its capability of producing cost effective composite products which exhibit all the features of other composites. The benefits of this technology are demonstrated by a variety of applications for different industries together with the more recent developments for the transportation industry.
1996-04-01
Technical Paper
91A098
Pierre G. Tabacot
An overview of high strength thermoset and thermoplastic composites will provide a basis of comparison with exotic hybrid composites. A specific theoretical application for a very high strength unibody application will be presented and test results evaluated. A critical overview of immediate applications will be presented and evaluated. In conclusion, it will be suggested that a uniform standard of performance be established for the practical application's requirements for these materials
1996-04-01
Technical Paper
91A097
Enzo Carrubba
The paper outlines the future trends for structural applications of composite in automotive. RTM, SMC and S-RIM seem to be the most promising technologies in this field. Parts made with epoxy resins in resin transfer molding technology have very good mechanical properties that allow them to be suitable for chassis applications coupled with steel parts. The SMC compounded with Derakane resin shows very good qualities in terms of temperature resistance and a reasonable high volume of production. The last technology rising is the S- RIM that seems to be very promising because of its short cycle time coupled with mechanical properties. Several examples of applications of these different technologies are showed in the paper; some of those are already in production some others are in an advanced phase of development.
1996-04-01
Technical Paper
91A117
P. Large, P. Laty, C. Rigaut
Mold designers and foundrymen spend a lot of time in developing molds without knowing exactly the phenomena which take place inside. Simulor, which has been used in an industrial environment for two years, offers the solution to make foundrymen understand what happens during the filling of the mold and the solidification of the part. Based on navier-stokes and heat transfer equations, simulor provides speed distribution and metal front evolution in the cavity and thermal map in the mold and the part. Some examples with different metals (cast iron, aluminum alloy) cast with various processes (sand or die casting, low pressure or gravity casting) will be given. This new tool will given foundrymen the opportunity to test the mold before having it machined and will also allow reduction in development delays.
1996-04-01
Technical Paper
91A121
J. P. Jameux, M. El Mouatassim, J. P. Dumesnil
In order to improve the design of drawn parts and to reduce the number of trial and error tests, Renault has undertaken the development and the validation of various finite element procedures and codes. This paper describes the function of each software and its level of integration into the design process. One of them is already an operational tool used be planners whilst the others are still in the validation phase. Selected examples show typical applications of the computer programs on automotive parts.
1996-04-01
Technical Paper
91A111
J. F. Monk
The pending changes in European law enabling the use of plastic lenses on vehicle headlamps provide an opportunity for further advancement of vehicle styling, lighting performance and aerodynamic efficiency. Plastic lenses can also provide a useful weight saving and contribute to energy savings during the lifetime of the vehicle. This paper discusses the current requirements, technologies and solutions for plastic lenses, and indicates the way this advance can impact on the evolution of lighting products.
1996-04-01
Technical Paper
91A122
G. Ferrari, E. Bianchin, R. Bonari, F. D'Oria
Processes involving use of reactive polymers received recently considerable attention also for producing components suitable for automotive structural applications. In particular polyurethane structural RIM technology seems to be the route of choice in terms of productivity, reliability and physico- mechanical performances in order to fit the automotive industry needs in the production of parts requiring superior load bearing properties. In this frame the development of long pot life snap-cure resins, fast and effective reinforcement preforming techniques as well as the development of computerized provisional processing methodologies are of paramount importance in view of industrialization of the technology. In this paper a description of the work carried out by Enichem Montedipe and Montedison is given. In particular a new family of PU systems, based on special isocyanate variants, is reported.
1996-04-01
Technical Paper
91A112
A. Salvetti, L. Lazzeri
The paper review some recent efforts, made by the aluminum industry, towards the development of new advanced alloys for aerospace applications; unconventional production technologies and MMC occupy an outstanding position in this context. Raid solidification processes are currently used for obtaining advanced alloys and, among them, the powder metallurgy route is one of the most commonly applied, since it has reached a considerable level of maturity. Experimental results of PM materials are shown and discussed in order to appreciate the potentialities of this class of materials and some recent further progress is shown: the spray deposition approach (osprey process). After having described the main features of the osprey process, some results obtained at the Department of Aerospace Engineering of Pisa about the development of high strength Al-alloy and MMC obtained by means of the osprey process are shown.
1996-04-01
Technical Paper
91A115
F. Pinna, E. Di Russo
Indirect squeeze casting technology is one of the most attractive fabrication techniques of near net shape components constituted by aluminum matrix composite (AMC) materials. AMCs reinforced with both continuous and discontinuous ceramic elements have been mainly produced by infiltration of porous preforms. Nevertheless, a further promising production route offered by this technique is given by the possibility to employ ingots of pre-reinforced aluminum alloys containing ceramic particles (silicon carbide or alumina); ingots are remelted and, under suitable operative conditions, high quality composite castings of simple and complex shape are produced by squeeze casting. The present paper describes the results of an extensive experimental work carried out by Alures-Centro Tecnico Porcessi on a pilot plant scale employing a vertical squeeze casting machine with a clamping force of 315 tons.
1996-04-01
Technical Paper
91A113
Renzo Moschini
Semi-liquid forming process, applied to pressure die-casting, permits to obtain low cost components with high qualitative characteristics and adequate mechanical performances. The technology is based on the employment of material with globular microstructure (flow-cast alloys) obtained subjecting a metal alloy at the time of solidification to an elevated shear rate. Such microstructure permits the accomplishment of conventional forming processes at temperatures in solidification range. The particular fluid-dynamic properties of the semi-liquid slurry and the lower injection temperature allow to obtain casting with improved soundness, without need of impregnation, and to extend die life. The present work describes the Weber (Magneti Marelli) activity of the process industrialization and some applications for the manufacture of automotive components.
1996-04-01
Technical Paper
91A116
D. F. Richter
Particulate reinforced aluminum composite is described and properties shown. Application of this material to specific components are discussed, and it is shown that significant progress has been achieved on the road to commercial automotive introduction.
1996-04-01
Technical Paper
91A114
C. Atzori, A. Prato
The following paper describes the experimental activity regarding the setting-up and characterization of a car engine bracket in Al-Si12Cu2FeZn-F alloy produced by the new technology squeeze casting. LExperimentation was carried out at the Alures squeeze casting pilot plant. Static and dynamic characterization (fatigue resistance on test samples and the component itself) was carried out at Teksid and Fiat Auto. Characterization test have demonstrated the considerable advantages offered by the new technology compared with conventional production processes.
2011-11-28
WIP Standard
AS5591
This specification covers the dimensions and performance requirements for optical contacts for AS5590 fiber optic connectors.
2006-01-31
WIP Standard
AS5672
To provide one single global standard for the handling of aviation fuel, through its delivery cycle from the refinery to on-board the aircraft
2006-04-10
WIP Standard
AS5677
Develop standards and specifications for PASSIVE Radio Frequency Identification (RFID) "smart labels " used for identifying aerospace parts and systems that will be used in airborne applications.
2010-05-19
WIP Standard
AS5466/1
This specification establishes envelope, port configuration, and part identification number system for line mount hydraulic quantity measuring fuses intended to be used for hydraulic circuit protection.
2007-08-28
WIP Standard
AS5811
Harmonize AS5551 Fig.1 / ABS0919 to Design Standard, AS-EA
2008-02-05
WIP Standard
AS5751
The document describes the pressure requirements for aircraft fuel systems as it relates to their refueling on the ground.
2008-03-06
WIP Standard
AS5753
Develop propsed AS5177 Cap Assy
2007-11-06
WIP Standard
AS5745
The latch standard will identify the performance requirements and some interface requirements for an over-center latch with the primary intended use being for closure and securing shipping and storage containers.
2003-01-01
Book
Igor V. Komarov, Sergey M. Smolskiy
Here’s a unique new resource that offers you a solid understanding of the fundamental theory, operation principles and applications of short-range frequency modulated continuous wave (FM CW) radar. You learn how to choose the structural scheme of short-range FM radar, and determine the optimal algorithm of useful signal processing necessary for ensuring the technical characteristic of radar. Moreover, this practical reference shows you how to ensure the minimum level of radar signal parasitic amplitude, calculate modulation signal distortion, and compensate for nonlinear distortion. For the first time in any book, you find detailed coverage of the theory and calculations of autodyne radar, helping you avoid typical mistakes with your work in this area. Other critical discussions include the parameters of UHF unit output signals and the principles of regime optimization.
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