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Mechanical and Metallurgical Analysis of HSLA Steel for Gas Tungsten Arc Welding with Different Shielding Gases

CSI College of Engineering-Dhanraj Gurusamy, Prashanth Murthy, Senthilkumar Ramakrishnan, Sivakumar Nanjappan
Sri Krishna College of Engineering and Technology-Soundararajan Ranganathan
  • Technical Paper
  • 2019-28-0069
To be published on 2019-10-11 by SAE International in United States
The special designed HSLA (High Speed Low Alloy) Steel is most commonly used in Naval Steel Structures and aircraft structures due to its indigenous properties. The aim of this paper is used to investigate the effect of shielding gases in the Gas Tungsten Arc Welding process. DMR 249A [HSLA] plates were welded by GTAW by using helium and argon as shielding gas with a flow rate of 16 L/min, the interpass temperature is 140 degree Celsius and the heat input is less than 1.2KJ/min where the impact toughness, Tensile and micro hardness was studied with different shielding gas and the metallurgical properties were analysed in the base metal, heat affected zones and weld zones. A detailed study has been carried out to analyze the elements using Scanning Electron Microscopy and Energy Dispersive Spectroscopy (EDS) analysis. The properties of the high speed low alloy steel carried out reveals a better mechanical properties suitable in naval applications.
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Landing Gear Integration into Aircraft Structure in Early Design Stage

Bauhaus Luftfahrt EV-Ulrich Kling, Mirko Hornung
  • Technical Paper
  • 2019-01-1890
Published 2019-09-16 by SAE International in United States
The demanded development towards various emission reduction goals set up by several institutions forces the aerospace industry to think about new technologies and alternative aircraft configurations. With these alternative aircraft concepts, the landing gear layout is also affected. Turbofan engines with very high bypass ratios could increase the diameter of the nacelles extensively. In this case, mounting the engines above the wing could be a possible arrangement to avoid an exceedingly long landing gear. Thus, the landing gear could be shortened and eventually mounted at the fuselage instead of the wings. Other technologies such as high aspect ratio wings have an influence on the landing gear integration as well. To assess the difference, especially in weight, between the conventional landing gear configuration and alternative layouts a method is developed based on preliminary structural designs of the different aircraft components, namely landing gear, wing and fuselage. Simplified parametric finite element structural models for the different components are introduced. These models are used to investigate different aircraft configurations with special regard on the landing gear integration. The…
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Measured Interfacial Residual Strains Produced by In-Flight Ice

Connecticut Reserve Technologies-Eric Baker
NASA John Glenn Research Center-Jonathan Salem, Richard Kreeger
Published 2019-06-10 by SAE International in United States
The formation of ice on aircraft is a highly dynamic process during which ice will expand and contract upon freezing and undergoing changes in temperature. Finite element analysis (FEA) simulations were performed investigating the stress/strain response of an idealized ice sample bonded to an acrylic substrate subjected to a uniform temperature change. The FEA predictions were used to guide the placement of strain gages on custom-built acrylic and aluminum specimens. Tee rosettes were placed in two configurations adjacent to thermocouple sensors. The specimens were then placed in icing conditions such that ice was grown on top of the specimen. It was hypothesized that the ice would expand on freezing and contract as the temperature of the interface returned to the equilibrium conditions. While results from the aluminum specimens matched this hypothesis, results from the acrylic specimens show a short period of contraction followed by a much larger expansion at the interface, indicating more complex ice growth thermodynamics than anticipated. Some samples were observed to delaminate, suggesting that the residual strain is significant to the shedding…
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Design of Lightweight Fibrous Vibration Damping Treatments to Achieve Optimal Performance in Realistic Applications

3M Company-Thomas Herdtle
Herrick Laboratories, Purdue University-Yutong Xue, J Stuart Bolton
Published 2019-06-05 by SAE International in United States
In recent work, it has been shown that conventional sound absorbing materials (e.g., lightweight fibrous media) can provide structural damping when placed adjacent to vibrating structures, including infinite panels, partially-constrained panels and periodically-supported panels typical of aircraft structures. Thus, a fibrous layer may serve two functions at once: absorption of airborne sound and the reduction of structure-borne vibration. It has also been found that the damping is primarily effective below the critical frequency of the structure, and that the damping results from viscous interaction between the fibrous layer and the evanescent near-field of the panel, in the region where incompressible flow caused by the panel vibration oscillates primarily parallel with the panel surface. By using a near-field damping (NFD) model based on the Biot model for acoustical porous media, it has been shown that a properly-optimized fibrous layer can provide levels of damping comparable with those provided by conventional, constrained-layer, visco-elastic, damping treatments. Based on the idea that vibrating structures exhibit a certain wavenumber/frequency response spectrum, the focus of the current study has been on…
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Multidisciplinary Design Analysis and Optimization of Aerospace Composites

Charles Lu
  • Progress In Technology (PT)
  • PT-201
Published 2019-04-30 by SAE International in United States
Multidisciplinary Design and Optimization of Aerospace Composite Materials is a collection of ten SAE technical papers focusing on the design analysis of aerospace composite structures from the perspective of various disciplines. The book concentrates on the following aspects: • Analytical methods for weight design of aircraft structures, including a parametric geometry model capable of generating dedicated models for both aerodynamic and structural solvers. • Methodologies for evaluating the structural performance of carbon/epoxy composite panels. • An aerodynamic design of flexible wings made of composite structures. • Thermal design and analysis of composite enclosures. • Methodologies for analyzing the acoustic performance of composite structures, including the design optimization method to evaluate the acoustic performance in terms of transmission loss (TL) of various composite panels. • The lightening effect on composites, presenting a theoretical method to compute the electrical current propagating through composite structures due to lightning strikes. • The issue of fire resistance as most polymer resins are flammable once the respective ignition temperatures are reached. • A probabilistic-based reliability analysis of the composite structures. The…
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Interface Protection - Ground Equipment to Aircraft

AGE-3 Aircraft Ground Support Equipment Committee
  • Aerospace Standard
  • ARP1558
  • Current
Published 2019-03-28 by SAE International in United States
This SAE Aerospace Recommended Practice (ARP) discusses damage to aircraft fuselages caused by ground equipment contact at servicing and recommends methods to be incorporated or considered in ground equipment design for protection against that damage.
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Collaboration in a Hybrid Team of Human and Robot for Improving Working Conditions in an Aircraft Riveting Process

SAE International Journal of Advances and Current Practices in Mobility

ZeMA gGmbH-Rainer Mueller, Matthias Vette-Steinkamp, Ali Kanso, Tobias Masiak
  • Journal Article
  • 2019-01-1372
Published 2019-03-19 by SAE International in United States
Aircraft production is facing various technical challenges, such as large product dimensions, complex joining processes, and organization of assembly tasks. Overcoming such challenges, as well as maintaining low tolerances and small batch sizes, is often difficult to achieve whilst retaining economic viability.ZeMA believes that a semi-automated approach is the most effective way to optimize aircraft section assembly. This can be achieved with a semi-automated riveting process for solid rivets, using Human-Robot-Collaboration in combination with an intuitive Human-Machine-Interaction operating concept.In the assembly of aircraft structures - in this scenario the aircraft aft section - the pressure bulk head is mounted to the section barrel. Two operators work collaboratively in uncomfortable, non-ergonomic positions, yet of course have to maintain exacting quality standards. In order to improve this process, a dynamic task sharing strategy between human and robot according to their respective skills, with due consideration given to ergonomic factors is proposed. The ideal solution involves placing a robot inside the section barrel. The robot’s workspace is expanded by mounting it on top of a lifting unit so…
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11 Reasons to Use Automated Metrology

SAE International Journal of Advances and Current Practices in Mobility

Electroimpact Inc.-Robert Flynn, Carson Miller
  • Journal Article
  • 2019-01-1369
Published 2019-03-19 by SAE International in United States
Aerospace structures manufacturers find themselves frequently engaged in large-scale 3D metrology operations, conducting precision measurements over a volume expressed in meters or tens of meters. Such measurements are often done by metrologists or other measurement experts and may be done in a somewhat ad-hoc fashion, i.e., executed in the most appropriate method according to the lights of the individual conducting the measurement. This approach is certainly flexible but there are arguments for invoking a more rigorous process. Production processes, in particular, demand an automated process for all such “routine” measurements. Automated metrology offers a number of advantages including enabling data configuration management, de-skilling of operation, real time input data error checking, enforcement of standards, consistent process execution and automated data archiving. It also reduces training, setup time, data manipulation and analysis time and improves reporting.This paper draws on experiences from a recent automated metrology project and examines some of the challenges and benefits of successful measurement automation.
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Lightweighting in Aerospace Component and System Design

  • Magazine Article
  • TBMG-33914
Published 2019-03-01 by Tech Briefs Media Group in United States

Lightweighting design is an extensively explored and utilized concept in many industries, especially in aerospace applications, and is associated with the green aviation concept. The contribution of aviation to global warming phenomena and environmental pollution has led to ongoing efforts for the reduction of aviation emissions. Approaches to achieve this target include increasing energy efficiency. An effective way to increase energy efficiency and reduce fuel consumption is reducing the mass of aircraft, as a lower mass requires less lift force and thrust during flight. For example, for the Boeing 787, a 20% weight savings resulted in 10 to 12% improvement in fuel efficiency. In addition to reduction of carbon footprint, flight performance improvements such as better acceleration, higher structural strength and stiffness, and better safety performance could also be achieved by lightweight design.

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Aircraft Tire Inspection - In-Service Removal Criteria

A-5C Aircraft Tires Committee
  • Aerospace Standard
  • ARP6225A
  • Current
Published 2019-02-13 by SAE International in United States
This document is for establishing tire removal criteria of on-wing civil aircraft tires only. This document is primarily intended for use with commercial aircraft, but may be used on other categories of civil aircraft, as applicable. The criteria are harmonized with the Care and Service Manuals of the tire manufacturers for both radial and bias tires.
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