Technical Paper collections have been re-named for better clarity and alignment.x

Your Selections

Design Engineering and Styling
Analysis methodologies
Failure analysis
Failure modes and effects analysis
Finite element analysis
Fuzzy logic
Mathematical analysis
Statistical analysis
CAD, CAM, and CAE
Calibration
Design processes
Vehicle integration
Downsizing
Measurements
Optimization
Rapid prototyping
Simulation and modeling
Computational fluid dynamics
Computer simulation
Hardware-in-the-loop
Mathematical models
Scale models
Vehicle styling
Virtual reality
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Committees

Events

Magazine

Series

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

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
To be published on 2020-03-10 by SAE International in United States
The Italian Aerospace Research Center is currently developing the design of a HAPS (High Altitude Pseudo Satellite). Different HAPS configurations have been proposed in recent years. Airbus Zephyr family and Aurora Odysseus are based on the flying wing configuration. Thales Stratobus is an airship, while Google Loon project is based on balloons. Our proposal concerns a hybrid configuration where the weight is balanced by both aerodynamic and aerostatic forces. In this paper we present the tools we have implemented to develop the conceptual design of our platform. The tools have been implemented in Mathworks Matlab® and Grasshopper® integrated with Rhino 3-D. In the Matlab environment, we have developed an optimization algorithm which can estimate some geometric and energetic global parameters of the platform (weight, surface, volume, required power, width, length and height) using as input the desired speed, altitude and period of the year in which the mission will be performed. In this algorithm, we have included a modelling of the principal subsystems affecting the overall platform weight and energy consumption and availability, the aerodynamic…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

A Study of Paradrogue Aerodynamics

Forrest Jack Mobley
  • Technical Paper
  • 2020-01-0027
To be published on 2020-03-10 by SAE International in United States
Scaled paradrogue models were designed, built, and tested for the purpose of possible UAS aerial refueling application. Paradrogue chute gore patterns were changed between three models and studied using wind tunnel testing and computational fluid dynamics simulations. Drag coefficient values, as well as vortex shedding characteristics through POD and DMD analysis, were compared between the three models, with an emphasis on possible affects on flight stability.
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Effects of Helical Carbon Nanotubes on Mechanical Performance of the Composite Bonded Joints

Wichita State University-Ramanan Sritharan, Davood Askari
  • Technical Paper
  • 2020-01-0029
To be published on 2020-03-10 by SAE International in United States
Most composite assemblies and structures generally fail due to the 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. The overall performance of any composite assembly largely depends on the performance of its bonded joints. Various techniques and processes were developed in recent years to improve mechanical performance of the composite bonded joints, one of which includes the use of nanoscale reinforcements within the adhesive layer in between the adherends. However, most prior research have been focused on use of straight carbon nanotubes (CNTs) and other nanomaterials in particle forms. The goal was to improve the properties of the adhesive film and their interfacial bonding effectiveness. Because CNTs are inert in nature, they should be covalently functionalized, before incorporating them into adhesive resins. CNTs can be functionalized using different chemicals to improve their interactions with…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Cable Impedance Calculations Employed in Designing Aerospace Electrical Power Systems

Astronics AES-Jon Fifield
  • Technical Paper
  • 2020-01-0037
To be published on 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 constructed 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 is not included in your SAE MOBILUS subscription, or you are not logged in.

Design of Elevons for a Hybrid VTOL-Blended Wing Body Unmanned Aerial Vehicle

Delhi Technological University-Amit Bainsla, Vikas Rastogi, Pranav Bahl
  • Technical Paper
  • 2020-01-0047
To be published on 2020-03-10 by SAE International in United States
The two primary requirements for a safe flight of a UAV are its stability and manoeuvrability. The purpose of this study is to design and validate elevons for a UAV having Blended Wing Body configuration which requires knowledge of various domains applied in a complex combination. Elevons are the unconventional control surfaces for the flying wings which will cause a pitching moment when moved in same direction and will cause a rolling moment when moved differentially and their preliminary design is affected by the function which is dominant. A MATLAB© code was written to decide the position, shape and size of elevons and later on accurately evaluated using high fidelity Computational Fluid Dynamics simulations. The MATLAB© code calculates the required roll time rate taking into consideration the longitudinal and lateral control requirements. Using this coupled approach of MATLAB© code and Computational Fluid Dynamics simulations significant optimization is achieved in designing the elevons.
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Integrated Electrical UAV Propulsion Design and Testing For High Efficiency

DARcorporation-Wanbo Liu, Drew Darrah, Joel Eppler
  • Technical Paper
  • 2020-01-0053
To be published on 2020-03-10 by SAE International in United States
This paper covers the design, modeling and analysis of an electric ducted fan system for sUAV (<55 lb) and the verification of predicted performance with test data. Analysis shows that the operating condition of the motor can significantly affect performance and should be considered when selecting or designing a rotor and vice versa. Motor manufacturers usually provide a list of compatible propellers for a motor design with thrust at RPM data coupled with gram per Watt efficiency. However, the gram per Watt value is not constant across the range of operation and a better modeling is needed depending on thrust requirements. Many of the electrical losses can be difficult to calculate directly, such as flux and iron losses in the motor and switching losses in the ESC. Incorporating an estimation/approximation of such losses during the rotor design phase enables a more accurate performance predication and a better overall system efficiency. Two rotors are designed to work inside of the duct and both have identical geometry except for a small blade pitch changes to increase maximum…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Correlation of Cylinder Head Gasket Sealing Analysis Results Between Gasket Element and 3D Continuum Element

Cummins Engine Co., Ltd.-Amit Ozarde
Cummins Inc.-Gene McNay
  • Technical Paper
  • 2020-01-0049
To be published on 2020-03-10 by SAE International in United States
A head gasket is a component that sits between the engine block/liner and cylinder head(s) in an internal combustion engine. Its purpose is to seal high pressure combustion gasses in the cylinders, seal coolant and engine oil transfer ports between the block and head and to ensure no leakage of gasses or fluids out of the block to head joint; as such, it is the most critical sealing application in an engine. In general practice, the load deflection(L/D) characteristic is generated by the gasket manufacturer for edge molded or composite gasket types. In the case of a solid-sheet metallic gasket, where the gasket is expected to undergo local yielding to provide adequate conformance and sealing, supplier is usually not able to provide the required L/D curve due to difficulties experimentally separating the large loads and small displacements from the elastic loads and deflections of the experimental apparatus. In absence of L/D curve the current analysis approach is to model gasket as 3D continuum elements with considering nonlinear material and contacts. The focus of the procedure…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

An Approach to Verification of Interference Concerns for Multicore Systems (CAST-32A)

Rapita Systems, Inc., Ltd.-Steven H. VanderLeest, Christos Evripidou
  • Technical Paper
  • 2020-01-0016
To be published on 2020-03-10 by SAE International in United States
The avionics industry is moving towards the use of multicore systems to meet the demands of modern avionics applications. In multicore systems, interference can affect execution timing behavior, including worst case execution time (WCET), as identified in the FAA CAST-32A position paper. Examining and verifying the effects of interference is critical in the production of safety-critical avionics software for multicore architectures. Multicore processor hardware along with aerospace RTOS providers increasingly offers robust partitioning technologies to help developers mitigate the effects of interference. These technologies enable the partitioning of cores for different applications at different criticalities and make it possible to run multiple applications on one specific core. When incorporated into system-design considerations, these partitioning mechanisms can be used to reduce the effects of interference on software performance. In this paper we describe a novel approach to verifying the effectiveness of RTOS interference mitigation on the final hosted software. We showcase the use of the proposed approach on the NXP T2080 multicore board. The approach follows a V-model based methodology in which high- and low-level requirements…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Application of Extended Messinger Icing Models to Complex Airframe Geometries

Georgia Institute of Technology-Avani Gupta, Lakshmi Sankar
NASA John Glenn Research Center-Richard Kreeger
  • Technical Paper
  • 2020-01-0022
To be published on 2020-03-10 by SAE International in United States
Ice accretion poses a major problem for civilian and military aircraft and rotorcraft, severely jeopardizing the safety and survivability of the vehicle. The development of analytical and empirical ice tools to understand the ice accretion process is crucial. Existing methodologies, such as the Messinger model employed by LEWICE, are able to predict ice shapes and growth on lifting surfaces such as wings and rotors relatively well. Extension of these methodologies to more complex configurations is needed. The methodology must be reasonably modular so that one can leverage future developments in computational fluid dynamics, structured and unstructured grid generation, and ice accretion models. Towards this goal, the following modular approach has been developed. 1. Do the unstructured grid based flow analysis. Save the grid and flow field in a standard format such as Plot3D or VGrid. 2. Compute the water particle transport using either the Lagrangian approach or an Eulerian approach. Where possible, public domain analyses, e.g. OpenFoam, are used in this step. 3. Compute the time rate at which water is deposited on the solid…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Accounting thermal exchanges in Coanda effect

Henri Coanda Labs LLC-Michele Trancossi
Universidade Da Beira Interior-Jose Pascoa
  • Technical Paper
  • 2020-01-0026
To be published on 2020-03-10 by SAE International in United States
Modeling Coandã effect has been a fundamental issue in fluid dynamic research in the XX century. It has lost some interest because of the improvement in CFD, even if it could be still important in the area of the preliminary design of aerodynamic devices that benefits of fluid deflection by convex surfaces. An effective model of Coandã effect has not been defined, and fundamental questions are still open. One of the problems which affect many practical cases, but it is still marginally approached by scientific literature, is the influence of convective heat exchange on Coandã adhesion of a fluid stream on a convex surface in the presence of a temperature gradient between the fluid and the convex surface. This paper aims to start an effective research direction on the effects of convective heat exchange on Coandã effect. It approaches the problem with a set of CFD simulations. It analyses the previous hypotheses, which are based on Prandtl number and evidences the need of a more effective model that account also Reynolds number.