The SAE MOBILUS platform will continue to be accessible and populated with high quality technical content during the coronavirus (COVID-19) pandemic. x

Your Selections

AeroTech
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Events

   This content is not included in your SAE MOBILUS subscription, or you are not logged in.
new

Tools for the Conceptual Design of a Stratospheric Hybrid Platform

CIRA - Italian Aerospace Research Centre-Vincenzo Rosario Baraniello, Giuseppe Persechino, Roberto Borsa
  • Technical Paper
  • 2020-01-0025
Published 2020-03-10 by SAE International in United States
CIRA is currently designing a HAPS for Earth Observation and Telecommunications named High Altitude Hybrid Airship. The configurations considered, can generate both aerodynamic and aerostatic forces to balance the weight during the different phases of a mission. The design of a hybrid configuration for stratospheric platforms represents a novelty in itself in the aerospace sector while some hybrid platforms have been proposed only for tropospheric applications. In order to carry out the conceptual design, some design tools have been implemented to rapidly obtain a conceptual layout, which can be used to perform CFD, FEM and stability analysis and, at the same time, to compute the relative platform mass breakdown. The proposed conceptual design process is based on two steps. A first coarse exploration algorithm which, starting from some input parameters, determines the best buoyancy ratio and some overall platform parameters (among others: weight, volume and dimensions) using some semi-empirical formulas to define sub-systems masses, aerodynamic coefficients and structures sizing. The second step consists in a finer optimization around the geometry obtained at the previous step,…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.
new

Effects of Helical Carbon Nanotubes on Mechanical Performance of Laminated Composites and Bonded Joints

Wichita State University-Ramanan Sritharan, Davood Askari
  • Technical Paper
  • 2020-01-0029
Published 2020-03-10 by SAE International in United States
Most composite assemblies and structures generally fail due to weak interlaminar properties and poor performance of their bonded joints that are assembled together with an adhesive layer. Adhesive failure and cohesive failure are among the most commonly observed failure modes in composite bonded joint assemblies. These failure modes occur due to the lack of reinforcement within the adhesive layer in transverse direction. In addition, the laminated composites fail due to the same reason that is the lack of reinforcement through the thickness direction between the laminae. The overall performance of any composite structures and assemblies largely depends on the interlaminar properties and the performance of its bonded joints. Various techniques and processes were developed in recent years to improve mechanical performance of the composite structures and assemblies, one of which includes the use of nanoscale reinforcements in between the laminae and within the adhesive layer. However, most prior research has been focused on use of straight carbon nanotubes (CNTs) and other nanomaterials in particle forms. The goal of this research was to improve the properties…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.
new

Advancements of Superplastic Forming and Diffusion Bonding of Titanium Alloys for Heat Critical Aerospace Applications

The Boeing Company-Eve Taylor Burkhart, Larry Hefti
  • Technical Paper
  • 2020-01-0033
Published 2020-03-10 by SAE International in United States
Titanium’s high strength-to-weight ratio and corrosion resistance makes it ideal for many aerospace applications, especially in heat critical zones. Superplastic Forming (SPF) can be used to form titanium into near-net, complex shapes without springback. The process uses a machined die where inert gas is applied uniformly to the metal sheet, forming the part into the die cavity. Standard titanium alpha-beta alloys, such as 6Al-4V, form at temperatures between 900 and 925°C (1650-1700°F). Recent efforts have demonstrated alloys that form at lower temperatures ranging between 760 and 790°C (1400-1450°F). Lowering the forming temperature reduces the amount of alpha case that forms on the part, which must be removed. This provides an opportunity of starting with a lower gauge material. Lower forming temperatures also limit the amount of oxidation and wear on the tool and increase the life of certain press components, such as heaters and platens. A variation of this process is SPF combined with Diffusion Bonding (SPF/DB) of two or more titanium sheets to produce integrally stiffened structures with limited fasteners and less weight than…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.
new

Advances in Drilling with PCD (Polycrystalline Diamond)

Facet Precision Tool GmbH-Jeremy Bunting, John Bunting
  • Technical Paper
  • 2020-01-0035
Published 2020-03-10 by SAE International in United States
PCD properties were optimized to drill stacks of CFRP/Ti using an accelerated wear test milling gray cast iron. The optimized PCD was then used to prepare PCD drills. Tests were made to determine the best drilling conditions for the optimized PCD. The results yielded a significant improvement in cycle times as compared to earlier studies using PCD drills. Notched PCD cutting edges were found to eliminate oversizing of the CFRP near the interface of the two materials.
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.
new

Cable Impedance Calculations Employed in Designing Aerospace Electrical Power Systems

Astronics AES-Jon Fifield
  • Technical Paper
  • 2020-01-0037
Published 2020-03-10 by SAE International in United States
This paper presents design considerations in utilizing cable impedance calculations in the design of an aerospace electrical power system (EPS). Past wiring design guidelines featured a tabular set of data based on a single-point design reference. This results in a cable selection which adds unnecessary weight and under-utilized the wire’s performance ability when considering a vehicle’s design requirements. Present wiring design guidelines have lagged behind the growing movement to achieve an optimized wire selection. Understanding the shortfalls with past and present wiring design methods will improve future methods to comply with increasingly restrictive vehicle performance requirements. This paper will discuss two of the most important design requirements for future aerospace electrical power and distribution feeders, which are weight and thermal limits assigned to an EPS design.
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.
new

System Integration in Aircraft Environment - Hydraulic Performances through Coupled Simulations

Airbus Operations GmbH-Henning Witt lng
Airbus Operations India-Ashutosh Singh
  • Technical Paper
  • 2020-01-0004
Published 2020-03-10 by SAE International in United States
An Airbus methodology for the assessment of accurate hydraulic performance at early program stages in the complete aircraft and power consuming systems environment based on joint collaboration with Chiastek is presented. The aim is to comfort the prediction of an aircraft hydraulic performance in order to limit the need for a physical integration test bench and extensive flight test campaign but also to avoid late system redesign based on robust early stage model based engineering and to secure the aircraft entry-into-service.
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.
new

Introduction to Control Volume Based Transient Thermal Limit

Army Corps Of Engineers-Mark Bodie
PC Krause & Associates-Rodney Yeu, Tim Deppen, Brian Raczkowski, Nicholas Jones, Eric Walters
  • Technical Paper
  • 2020-01-0039
Published 2020-03-10 by SAE International in United States
Advancement in modern aircraft with the development of more dynamic and efficient technologies has led to these technologies increasingly operated near or at their operation limits. More comprehensive analysis methods based on high-fidelity models co-simulated in an integrated environment are needed to support the full utilization of these advanced technologies. Furthermore, the additional information provided by these new analyses needs to be correlated with updates to traditional metrics and specifications. One such case is the thermal limit requirement that sets the upper bound on a thermal system temperature. Traditionally, this bound is defined based on steady-state conditions. However, advanced thermal management systems experience dynamic events where the temperature is not static and may violate steady-state requirements for brief periods of time. Due to the large thermal time constants for many components, such transient violations may not represent system failure and an understanding of transient temperature limits is beneficial. To meet this need, this paper introduces the transient thermal limit via control volume representation. Instead of a constant thermal limit, the transient thermal limit approach generates…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.
new

A Systematic Approach to Development Assurance and Safety of Unmanned Aerial Systems

Textron Aviation-Cory R. Laflin
  • Technical Paper
  • 2020-01-0043
Published 2020-03-10 by SAE International in United States
The unrestrained design space for unmanned aerial systems (UAS) presents challenges to accurate safety assessment and the assurance of development to appropriate levels of rigor within those systems. The established safety and development assurance standards and practices were developed for vehicles operating in highly controlled conditions with continuous oversight. The very nature of unmanned systems introduce new failure conditions, even in those systems operating within the strict rules of the National Airspace System (NAS), particularly failures of control and command, situational awareness, and control security. Beyond those, the new concepts of operation being conceived by UAS developers introduce their own new set of considerations with regards to operating in uncontrolled airspace, often in close proximity to bystanders. These new concepts require new technologies beyond those currently supported by the hardware and software development assurance processes. However, the established standards and practices of aircraft development assurance and safety assessment can be adapted for the broader world of UAS applications, provided that the considerations driven by the new concepts of operation can be identified and properly analyzed.…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.
new

Extended Endurance Unmanned Aerial Vehicle via Structural Electrical Power Storage and Energy Generation Devices

Geoffrey Smith Oetting
  • Technical Paper
  • 2020-01-0041
Published 2020-03-10 by SAE International in United States
As the application of unmanned aerial vehicles (UAV) have increased in the military, commercial and private sectors, special attention has been focused on improving upon high altitude long endurance (HALE) performance. Therefore, under a multi-year, multi-discipline senior project team comprised of Aerospace Engineering, Electrical Engineering, Computer Engineering, Mechanical engineering, and Chemical Engineering undergraduate teams, investigative and experimental research has begun into the substitution of various aircraft structural components with power storage and power generation devices used also as structure to improve flight endurance and performance capabilities of solar powered UAVs. One viable solution may be found in the reduction of the amount of parasitic weight due to the required power systems on board these types of aircraft. These power systems are usually found in the form of energy storage devices such as lithium polymer batteries and energy generation devices such as solar cells. This path led to the innovation of the ‘Flying Battery’. The ‘Flying Battery’ integrates various free energy generating devices such as structural solar cells, structural energy storage devices, thermo-electric generators, and vibration…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.
new

Item Level Serialization and Traceability of Aerospace Fasteners Based on Individual Inherent Surface Patterns

Arconic Fastening Systems-Luke Leonard Haylock, Jens Harde, Jürgen Rösing, Nils Murray, Torsten Timpe
fraunhofer-Tobias Schmid-Schirling, Norbert Saum lng, Daniel Carl
  • Technical Paper
  • 2020-01-0012
Published 2020-03-10 by SAE International in United States
Item level serialization traceability, defined as the ability to track and trace products, items or components through the supply chain from product manufacturing all the way to the end of life service, has significant value in the aerospace industry. Many items become susceptible to counterfeiting when their origin and authenticity cannot be verified and Item level serialization and traceability fosters supply chain integrity. Data Matrix and radio-frequency identification (RFID) are two common methods that enable detailed information about the manufacturer. However, these methods are not generally compatible with fasteners due to the small size of the fasteners and the cost of these methods. Fasteners are the most commonly used parts on an aircraft and rely on lot level traceability associated with packaging to provide a level of supply chain risk management. However, the association of individual fasteners to parental lots is often lost once the fasteners are removed from packaging. We demonstrate a completely new approach to develop item level serialization traceability for aerospace fasteners. It is demonstrated that this label-free traceability can be realized…