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Viewing 181 to 210 of 19780
2014-09-16
Journal Article
2014-01-2230
Ruiqiang Lu
Abstract With the development of many new technologies in aircraft manufacturing area and the increasing competition of the global market, aircraft manufacturing enterprises have to reduce their production time and increase the cost-efficiency, with the consideration of high speed response to the changes inside enterprises or in the environment. Production scheduling is a significant process in manufacturing, especially for complicated part or component processing. This paper proposes an agent based multi-objective optimization approach for production scheduling based on Genetic Algorithms. It aims to minimize the total production cost and simultaneously reducing the emission released during production, and the delivery time and equipment constraints are satisfied as well. The new approach is tested in a virtual plant for turbine blade manufacturing.
2014-09-16
Journal Article
2014-01-2241
Jamie Skovron, Laine Mears, Durul Ulutan, Duane Detwiler, Daniel Paolini, Boris Baeumler, Laurence Claus
Abstract A state of the art proprietary method for aluminum-to-aluminum joining in the automotive industry is Resistance Spot Welding. However, with spot welding (1) structural performance of the joint may be degraded through heat-affected zones created by the high temperature thermal joining process, (2) achieving the double-sided access necessary for the spot welding electrodes may limit design flexibility, and (3) variability with welds leads to production inconsistencies. Self-piercing rivets have been used before; however they require different rivet/die combinations depending on the material being joined, which adds to process complexity. In recent years the introductions of screw products that combine the technologies of friction drilling and thread forming have entered the market. These types of screw products do not have these access limitations as through-part connections are formed by one-sided access using a thermo-mechanical flow screwdriving process with minimal heat.
2014-09-16
Journal Article
2014-01-2242
Samuel Baha II
Hybrid (bolted/bonded) joining is becoming one of the innovative joining processes for light weight structures in the transport industry, especially in the aerospace industry where weight reduction and high joining requirements are permanent challenges. Combining the adhesive bonding with the mechanical joining -riveting for instance- can lead to an enhancement of the properties of the joint compared to the wide established riveting, as a result of a synergistic load bearing interaction between the fastener and the adhesive bondline. The influence of the rivet installation process on a hybrid joint regarding the joint stress state, the change of the bondline thickness as well as its effects on the joint performance and load transfer are some of the factors that drive the users to a better understanding of the hybrid joining process.
2014-09-16
Journal Article
2014-01-2236
Julian Lonfier, Côme De Castelbajac
Abstract As aircraft programs currently ramp up, productivity of assembly processes needs to be improved while keeping quality, reliability and manufacturing cost requirements. Efficiency of the drilling process still remains an issue particularly in the case of CFRP/metal stacks: hot and long metallic chips are difficult to remove and often damage the surface of CFRP holes. Low frequency axial vibration drilling has been proposed to solve this issue. This innovative drilling process allows breaking up the metallic chips in such a way that jamming is avoided. This paper presents a case of CFRP/Ti6Al4V drilling on a CNC machine where productivity must be increased. A comparison is made between the current regular process and the MITIS drilling process. First the analysis and comparison method is presented. The current process is analyzed and its limits are highlighted. Then the vibration process is implemented and its performances are studied.
2014-09-16
Journal Article
2014-01-2240
Joshua Norman, Cesar Moreno, Zhiyu Wang, James Mann, Christopher Saldana
Abstract The beneficial effects of contact disruption in modulation-assisted machining of aerospace alloys have been well documented, but sources for such improvements are not well understood. This study explores the underlying nature of differences that occur in energy dissipation during conventional and modulation-assisted machining by characterizing the relationship between controllable process parameters and their effects on chip formation. Simultaneous in situ force and tool position measurements are used to show that the forces in modulation-assisted machining can be described by empirical force models in conventional machining conditions. These models are found to accurately describe plastic dissipation over a range of modulation conditions and configurations, including in cases where energy expenditure decreases with the application of modulation.
2014-09-16
Journal Article
2014-01-2258
Sylvain Laporte, Etienne Gueydon, Alain Auffret, Cosme De Castelbajac
Abstract In today's aircraft assembly process several new features make drilling operations very challenging according to production requirements. Parts are made of thin or thick multi-material stacks with a large scope to cover and complex assembly sequences. In addition, the current ramp-up in aircraft programs involves to improve productivity while keeping process quality and reliability. In this context robotic solution meets perfectly all these requirements as it is flexible, reconfigurable, fast and agile. Among the possible end-effectors, the Barrel Multi-Function End Effector (BMFEE) appears to be the most flexible solution to allow many different process configurations. The latest developments have been focused on the drilling equipment of this BMFEE. In fact the drilling process efficiency can be constantly improved especially in terms of reliability, quality and productivity. Therefore vibration-assisted drilling system has been integrated into the BMFEE drilling module.
2014-09-16
Journal Article
2014-01-2271
Ryan Haldimann, Daniel Orf
Abstract In an attempt to be more flexible and cost effective, Aerospace Manufacturers have increasingly chosen to adapt a manufacturing style which borrows heavily from the Automotive industry. To facilitate this change in methodologies a system for locating robots has been developed which utilizes cameras for both locating and guidance of a mobile platform for a robot with drilling and fastening end effector.
2014-09-12
Article
High-performance metamaterial antennas could be compact, lightweight, conformable, and stealthy.
2014-09-11
Standard
AS4228C
Scope is unavailable.
2014-09-11
Standard
AMS4361
This specification covers an aluminum alloy in the form of plate products from 1.000 to 6.000 inches (152.40 mm) in thickness. 7065-T7451 may be used in aerospace applications requiring high strength and fracture toughness, high resistance to stress-corrosion cracking and good resistance to exfoliation corrosion, but usage is not limited to such applications.
2014-09-11
Standard
AMS4351
This specification covers an aluminum alloy in the form of plate products from from 1.000 to 6.000 inches (152.40 mm) in thickness. 7065-T7651 may be used in aerospace applications requiring high strength and good fracture toughness, good resistance to stress-corrosion cracking and to exfoliation corrosion, but usage is not limited to such applications.
2014-09-09
Standard
J176_201409
This SAE Standard applies to off-road self-propelled work machines as categorized in SAE J1116. Fast fill fueling typically applies to self-propelled machines with a fuel capacity over 380 L, although fast fill fueling can be used on machines with smaller fuel capacity.
2014-09-09
WIP Standard
ARP1917B
This Aerospace Recommended Practice (ARP) clarifies terms used in Aerospace materials and process specifications. The terms clarified in this ARP are not intended to supersede those terms for which clarification is already provided in existing specifications.
2014-09-09
WIP Standard
J78
This SAE Standard covers the dimensional and general specifications, including performance requirements, for carbon steel self-drilling tapping screws suitable for use in general applications. It is the objective of this document to insure that carbon steel self-drilling tapping screws, by meeting the mechanical and performance requirements specified, shall drill a hole and form or cut mating threads in materials into which they are driven without deforming their own thread and without breaking during assembly. Appendix A is included to provide a recommended technique for measuring the case depth on the screws.
2014-09-08
Article
The Walmart Advanced Vehicle Experience is a prototype tractor-trailer developed to demonstrate the possibilities of future transport, and the truck is not the only place where innovation reigns. The trailer body is built almost exclusively with carbon fiber, and it incorporates other technologies such as advanced adhesives and low-profile LED lighting.
2014-09-05
Article
Days before Tesla on Sept. 4 announced it has selected Nevada as the state in which it will build a large "Gigafactory' battery plant, Lux Research opined that the savings in lithium-ion battery costs owing to high-volume efficiencies will not be as much as the automaker expects it to be.
2014-09-05
Standard
AMS3217/7A
This specification covers a high strength fluorosilicone (FVMQ) rubber stock in the form of molded test slabs.
2014-09-05
Standard
AS291F
This standard provides a method of applying surface roughness, waviness and lay control. The data included herein also covers the method of applying surface roughness symbols and related designations to drawings and specifications of parts when applicable. This standard is based on the Arithmetical Average (AA) method of instrumentation. Data compiled are based on current manufacturing practices. It also includes a summary of data published in the latest issue of the American Standards Association publication ASA B46.1.
2014-09-03
WIP Standard
AMEC14AC
This appendix establishes the procedures, guidelines and requirements for qualification and quenching of parts produced from the alloys listed in AMS2759/2, Table 2 using inert pressure gas in vacuum furnaces.
2014-09-01
Journal Article
2014-01-9002
Zachary A. Collier, Steve Walters, Dan DiMase, Jeffrey M. Keisler, Igor Linkov
Counterfeit electronic components entering into critical infrastructure and applications through the global supply chain threaten the economy and national security. In response to the growing threat from counterfeits, the Society of Automotive Engineers G-19 Committee is developing AS6171. This aerospace standard is focused on testing facilities with a goal of standardizing the process of counterfeit detection. An integral part of the standard is a semi-quantitative risk assessment method. This method assigns risk scores to electronic components based on a number of relevant criteria, and places the components into one of five risk tier levels corresponding to an appropriate level of laboratory testing to ensure the authenticity of the component. In this way, the methodology aims at standardizing the risk assessment process and bases the identified risk as guidance for commensurate testing protocols.
2014-08-26
Standard
AS7351A
Scope is unavailable.
2014-08-26
Standard
AS6462A
This set of criteria shall be utilized by accredited Certification Bodies (CBs) to establish compliance, and grant certification to AS5553A, Aerospace Standard; Counterfeit Electronic Parts; Avoidance, Detection, Mitigation, and Disposition.
2014-08-25
Article
Coriolis Composites and SAFRAN Aircelle worked together on a thrust reverser component demonstrator made with carbon-fiber-reinforced plastic (CFRP) material and an AFP process. This component is an inner fixed structure, made of two monolithic carbon skins and a core.
2014-08-25
Standard
AMS6378G
This specification covers a free-machining, low-alloy steel in the form of round bars 3.50 inches (88.9 mm) and under in nominal diameter.
2014-08-22
Standard
AMS6324J
This specification covers an aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock.
2014-08-22
Standard
AMS6382P
This specification covers an aircraft-quality, low-alloy steel in the form of bars, forgings, flash welded rings, and stock for forging or flash welded rings.
Viewing 181 to 210 of 19780

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