selex galileo case study
TRANSCRIPT
8/3/2019 SELEX Galileo Case Study
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Challenge
Producing a surface mesh of around 100 million elements required breaking down the
geometry into smaller models, whose surface areas needed to be individually small enough
for the surface meshing algorithm to efficiently mesh. This required integrating a mechanical
model into a microwave simulation tool and using EM solvers to generate high quality surface
meshes of electrically small elements.
All elements had to be electrically small, with a guideline of triangle edge length between
λ/8 and λ/12 to give a suitable compromise with solution stability and size of problem. Also,
generating a large quantity of small elements would have an impact on memory and runtime
requirements, so an optimum triangle length would be required.
Using HyperWorks to Generate Electrically Large Surface
Meshes for Radar Cross Section or Antenna PlacementSimulation
HyperWorks is a division of
Case Study
Overview
Radar Cross Section (RCS) and installed antenna placement are important parameters for
aircraft designs. RCS is a measure of how detectable an object, such as an aircraft, is with
radar. A large RCS indicates that an object, such as a jet aircraft, is easily detected.
SELEX Galileo used HyperWorks to generate arbitrarily large surface meshes, with defined
electrical properties at the element level, for use with electromagnetic (EM) solvers to
calculate either RCS of an aircraft or to determine where to place an antenna for optimum
performance.
For this case study a fast-jet aircraft with approximately 100 million mesh elements was
assessed for radar tracking and avoidance capabilities.
Business Profle
SELEX Galileo, a Finmeccanica Company, is a leader in defence electronics markets, with a
distinctive strength in airborne mission critical systems and a wide range of capabilities for
the battlefield and for homeland security applications.
SELEX Galileo is a truly global business and employs 7000 staff across 5 continents.
Fig. 1: Sample Installed Antenna Pattern for Fast-Jet
Fig. 2: Sample RCS of Fast-jet about
Elevation Plane
www.altairhyperworks.co.uk
“HyperWorks has given us
the capability to generate
large meshes easily which
has led to reduced risk
and costs for designs that
have integral microwave
elements”
Rob Cook
Selex Galileo
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Altair Engineering Ltd Imperial House, Holly Walk, Royal Leamington Spa, CV32 4JG, UK
Phone: 01926 468 600 • Fax: 01926 468 601 • www.uk.altair.com • [email protected]
Solution
SELEX Galileo used HyperMesh to generate the large quantities of small elements andapplied the numerical Method of Moments (MOM) model to describe how large, complex
structures would interact with EM fields.
A formula known as the Multi-Level Fast Multipole Method (MLFMM) was developed to better
deal with large structures by an iterative boxing of the structure into smaller and smaller
sections. This allows a reduction in the problem size, both in terms of memory requirements
and runtime.
To help generate these models, Altair developed an automation process that enabled SELEX
Galileo to sub-divide the full model. Once the full model was divided into small enough
components, a mesh was applied to the curves that defined the interfaces between each
component. This produced a series of nodes that bridged the sub-components.
Each of the sub-models that made up the full model was then written to an individual file.
Once the submodels were checked they were assigned electrical properties with various
parameters for each element, checked to ensure correct element properties, and then
assigned electrical properties specific to the EM solver in question.
Altair HyperWorks
Modeling and AssemblyRobust Design
Optimization
Design Analysis
Visualization
Reporting
Virtual Manufacturing
Process Automation
Data Management
For more information please visit
www.altairhyperworks.co.uk
Fig. 4: Example of Nodes Defined
Between Adjacent Components to
Ensure Mesh Continuity
Fig. 5: Sub-Divided Model of Fast
Jet Aircraft ~3 Million Elements per
Component
Fig. 3: Distributions of Triangle Edge Length
0 5 10 15 20 25 30
Triangle Edge Length
N o r m a l i s e d P o p u l a t i o n D e n s i t y Unacceptable
Acceptable
OptimisedFailure Region
Results
A process automation toolset was developed using HyperMesh to generate 100 million high
quality surface mesh elements for RCS and installed antenna performance simulations. It
demonstrated that mesh quality requirements could be aligned between meshing algorithms
and the EM solver, reducing need to rework exported meshes. This process allowed the
generation of arbitrarily large meshes without a limit set by local computing resources.
Integration with an EM solver based on MLFMM has given SELEX Galileo engineers the
capability to set electrical properties of the model in a GUI environment, which was previously
not available. The integration with the EM solver also allowed legacy models to be read into
a meshing environment, modified and have electrical properties assigned.
HyperWorks has helped SELEX Galileo designers to reduce development time of large EM
models, which will drive cost out of design activities.