EMA - pes-spdc.orgpes-spdc.org/sites/default/files/presentations/EMA3D for Wind... · Solid Rocket Booster ... launcher in Germany ... ELECTRO MAGNETIC

ELECTRO MAGNETICAPPLICATIONS, INCEMA

Full Wave EM Simulation forLightning Protection

Tim McDonald, [email protected]

Phone: +1 (303) 324-7532www.ema3d.com

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Electro Magnetic Applications, Inc.

• Electromagnetic environmental effects simulation andtesting since 1978

• Rod Perala, president, has been with EMA since 1978• Commercial software development and consulting

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• Over 30 years of softwaredevelopment, consulting,contract R&D

• Lightning Testing

• ESD

• EMC/EMI• Measurement and

Simulation

• F-14, F-18, Pershing II,Space Shuttle, Sikorsky,GPS Multipath, Cargo Lifter

EMA History

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Lightning Testing: Space ShuttleSolid Rocket Booster (SRB)

• EMA designed testgenerators and facilitybuilt in Wendover,Utah

• Tested several SRBcomponents

• Photo shows testing offirst stage

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Lightning Test Facility inWendover, Utah

• Wire gridpeakingcapacitor

• 1 million voltMarxgenerator

• 500 KAcurrent bank

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Static Electricity:Charging of Aircraft by Dust

• Iraqi dust storm• P-Static effects on

aircraft electronicsystems have beenobserved

• EMA• Developed a description of

the dust environment

• Determined charging ratesof dust on aircraft bymeasurement

• Determined dischargecurrents by analysis andmeasurements

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Measurement of Dust Charging ofAircraft Surface Materials

Example test setup Illumination of test sample

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Design and Simulation of AnechoicChambers (Lehman Chambers)

Combination of carbon loadedpyramids and ferrite tiles

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Anechoic Chambers: Comparison ofMeasured and Computed Results

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Triggered Lightning Simulation on 265mlong Airship

Lightning protectionstrips


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.mkV10axE

Electric Field Enhancement FactorsAxial Field

90 kV/m


Pershing II Accident Investigation

• In 1985, a PII caught fireduring assembly on its mobilelauncher in Germany

• EMA determined the cause tobe static charging of motorcase while inside its steelshipping canister

• An external static dischargeinduced a discharge insidethe propellant with theKevlar motor case

• Demonstrated by extensiveanalysis and full scale testing

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Railroad EM Effects• In 1997, EMA first became involved

in railroad electromagnetic effects• Lightning protection of railroad

signal systemsFaraday cage implementation inside

bungalowsDevelopment of a new arrester

• Interference of power lines withrailroad signal systems

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Civilian Aviation and Emerging TechnologiesEMA has worked on lightning, HEMP, and HIRF qualification ofcivilian aircraft as well as supporting internal prime contractor andgovernment R&D.

EMA TodayLockheed Martin’s Orion EM TeamLightning and space plasma charging effects for returning humansto space beyond low earth orbit.

GMD Ground Based Interceptor TeamMember of incumbent GMD team working on GBI upgradeand maintenance through its lifecycle.

Worldwide Software Sales and TrainingEMA has successful software sales worldwide aiding E3 and EMCengineers in aerospace, maritime, and automotive applications.

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Active Certification/Design Projects(Lightning)

• Super Medium Helicopter

• Regional Jet

• Midsize Business Jet• Two Narrow-body, Medium-

range Jet Airliners (1 active, 1 innegotiation)

• Missile Defense Agency Rocket

• Orion NASA Crew Vehicle

• Low-wing Turboprop Trainer

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EMA Committee Participation

• SAE Technical Committee AE-2 Lightning All facets of aircraft lightning strikes and its effects on aircraft-design, testing, measurement,

procedures, and in-service experience. Rod Perala was on the SAE AE2 from 1981 to 2001, where he helped to develop lightning

qualification waveforms and standards that are in use today. Since 2001, Greg Rigden of EMA has been on the committee and is chairman of the

environment subcommittee to update the lightning environment standards to conform to newresearch results.

• SAE Technical Committee AE-4R HIRF All facets of HIRF effects on aircraft-design, testing, measurement, procedures, and in-service

experience. Rod Perala was on the SAE AE4R from its beginning in about 1986 until about 1996. This committee developed the original environments and certification approaches and test

methods for HIRF certification. EMA also did some specialty tasks for the FAA related to HIRF risk assessment, which resulted

in some FAA technical reports.

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The Lightning Problem

• Design Phase: Need analysis to support system designbefore any testable prototypes exist.

• Certification Phase: Need an experimentally validatedmodel to reduce test costs and ensure viability in allpossible scenarios.

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The Lightning Problem

• The lightning levels are specified for the entiresystem

• There are no test levels for individual elements• Lightning effects depend on current distribution in

the entire system

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However . . .

• The system may not yet exist for testing

• If it does exist, full-scale lightning testing is expensive

• Full-scale testing is complicated by the ground plane and returnconductor system effects (ARP 5583 requires additional simulationsupport to full-scale testing)

• A limited set of attachment scenarios can be practically assessed• Design changes after the test are a problem

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Status Quo Approaches

• Use the test results of a previous project• Use poorly-suited analytical methods with a great

deal of margin

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Status Quo IssuesUse the test results of a previous project:

• The materials (use of composites) and bonding designmay be significantly different between designs

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Current Generation ofComputational Electromagnetics

• Mature codes (continuously under developmentsince 1978 and applied to hundreds of systems)

• Optimized for system level electromagneticsincluding lightning in complex systems

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Simulation Work FlowOriginal CAD

drawing

From Mech. Eng. Designers

CEM CADEnvironment

Imports CAD formats

3D CEM

Solves down to20 mm resolution

Harness Sim.

Transients/levels atpins/interfaces

CouponTesting

Experimental testlevels by analysis

ActionableResults

• Actual Transient Levels• Model Validation• Design Requirements• Tailored Test Levels• Design Evaluation• Certification Support

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Composite Materials

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• Complex material modeling challenges with individualcomposite layers and interaction with fasteners


Understanding Composite TestCoupon Properties

• EMA has developed methods to measure individual layeranisotropic conductivity properties

• A simulate-measure-simulate approach ensures a completeunderstanding of current distribution in each couponscenario

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Experimentally ValidatedApproach

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Representing Composite Joints inSimulations

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Validation

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• EMA has achieved a successful validation of simplified boxes• This lowers the cost versus a full wing validation and allows for use of

simulation results in certification


EMA Validation Heritage

• EMA has been doing this since one of the first composite fueltanks was placed in SAAB Gripen Fighter

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Validation Heritage

• MD-80 Simulation Compared to Test Data• High degree of correlation allowed for IEL

certification of MD-90 by simulation

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Recent Validation

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Fuel System validation Object

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Results

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Integrated Harness Simulation

• Lightning: MHARNESS gives transients at the pinlevel. Necessary for accurate results.

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Simulation Platform Size

• EMA3D integrated with MHARNESS is available as acluster version to operate in parallel over many nodes

• Extremely efficient scaling on computational clusters• Successfully used to simulate entire aircraft and large

systems35


Lightning Redistribution

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Current on Ribs

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Pipe and Cable Currents

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Wind Turbine Simulation Example

CAD imported from STEP format

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Cables

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New Cables in EMA3D CAD

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FDTD Cartesian Mesh (50 mm)

Meshing operation takes < 5 minutesAll materials are steel

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Cable Cross Section

Cable 1 Cable 2 Cable 3

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EMA3D Cable Cross Section Tool

EMA3D has the uniquecapability of Co-simulatingwith a full-featuredTransmission Line Solver

•Ability to quickly calculatethe accurate capacitance andinductance matrix for cablecross-section•Easy drag and drop cablecross section tool

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Material Library

EMA3D includes built-in sampleproperties for standard types ofcables•Diameter•Resistance•Transfer impedanceparameters

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Computational Simulation

CEM simulation completed in about two hours•Gradual permittivity scaling speeds up time-domainsimulation by a factor or more than ten•Built-in parallel simulation capabilities allow for speedup over 100 times on multi-core workstations andcomputational clusters

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Magnetic Field Slice Probe

LightningChannel

Log of H-field normal to page is proportional to color47


Current Density Animation

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Source Waveform

•The first case will be the standard 200 kA Component AWaveform 1 (~ 5 μs peak, slow fall)

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Waveform 1 Overall Cable BundleCurrent

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Waveform 1 Individual PinCurrent

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Waveform 1 Individual Pin Voltage

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DC Simulation

Gradual permittivity scaling allows for a time-domaincalculation of a ramp up to DC as described.•Simulation completed in a little over an hour•Impossible to complete with other time-domain solvers

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Ramp to 800 A DC SimulationResults: Pin Currents

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Summary

• Computation electromagneticsis critical for model complexsystem design and verification

• New simulation techniquesinteroperate with CAD

• Mature validation heritagemeans that the results can betrusted

• Applicable to wind turbinesand related systems

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Contact us with any questions!

Tim McDonald, PhD11 October [email protected]

Phone: +1 (303) 324-7532www.ema3d.com

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Documents

EMA - pes-spdc.orgpes-spdc.org/sites/default/files/presentations/EMA3D for Wind... · Solid Rocket Booster ... launcher in Germany ... ELECTRO MAGNETIC