Engineering Design Handbook - Hardening Weapon Systems against RF Energy:

153 Pages·2016·9 MB·English

AMC PAMPHLET AMCP 706-235
ENGINEERING DESIGN
HANDBOOK
HARDENING WEAPON SYSTEMS
AGAINST RF ENERGY
HEADQUARTERS, U.S. ARMY MATERIEL COMMAND FEBRUARY 1972
AMCP 706·235
LIST OF ILLUSTRATIONS
Fig.No. Title Page
2-1 FrequencySpectrum . 2-5
2-2 RelationshipofNear Fieldand Far Field . 2-8
2-3 Antenna Patterns . 2-10
2-4 ChargingbyInduction . 2-11
2-5 PotentialAccumulationon Vehicles With RubberTires . 2-12
2-6 StaticDissipatorUsedon Aircraft . 2-13
2-7 AccumulationofStaticElectricitybyHelicoptersand B-707Jet Aircraft . 2-14
2-8 Exampleofan Induced Chargeon an UngroundedSystem .•............... 2-15
2-9 ElectricalIntensityE and Potential V at Points Insideand Outsidea Charged
SphericalConductor . 2-17
2-10 TheStaticChargeDistributionfromOverheadThunder Cloudona Missileand
Carrier . 2-19
2-11 InstallationofStaticElectricityBleedResistors . 2-21
2-12 SequentialPhenomenain the Formulation ofLightningDischarge . 2-22
2-13 AverageAnnual NumberofDaysWithThunderstorms (World) . 2-23
2-14 ElectricFieldofaLightningStrokeResultingfromtheLeaderandMainStroke 2-25
2-15 GeneralizedWaveShapeofLightning-strokeCurrent . 2-26
2-16 NormalizedAverageAmplitudesfrom a Number of Observationsas a Source
Spectrumfor LightningDischarges . 2-26
2-17 StaticElectricFieldPrecedinga Thunderstorm . 2-27
2-18 MaximumRate ofChangeof the ElectricField in the Vicinityof a Lightning
Stroke . 2-28
2-19 SurfaceCurrents Induced on ConductiveEllipsoidsof Revolution by Nearby
LightningStrokes . 2-32
2-20 MaximumMagneticFlux DensityfromMainStrokeofLightning . 2-33
2-21 PotentialInducedina LoopasaResultofthe MagneticFieldfromaLightning
Discharge . 2-34
2-22 RadialElectricFieldin the Earth Surroundinga LightningStroke . 2-35
2-23 SurgeCurrent MagnitudesProducingPermanent Faults in TelephoneCable .. 2-36
2-24 FusingCharacteristicsofWireUsedin TelephoneDistribution . 2-37
2-25 EstimatedLightningStrokeCurrentRequiredtoProduceCore-to-sheathVoltage
of2 kV . 2-38
2-26 Pins-to-caseVoltageAppliedtoRocketIgniterSquibsbyDirectLightningStroke 2-41
2-27 DesiredOperatingCharacteristicsofLightningArresterforProtectionofBushing
and Winding . 2-42
2-28 One-to-oneand Two-to-oneProtection Zonesfor VerticalMastsand Overhead
Wires . 2-43
2-29 Protector BlockCommonlyUsedbyTelephoneCompaniesfor SurgeProtection 2-44
2-30 Arrangementto ProvideLow-voltage BranchCircuitProtection . 2-46
2-31 MeggerGround Tester . 2-51
2-32 Earth Radial Field Producing Pins-to-caseHazard as a Result of Improper
Grounding Procedures . 2-52
3-1 A CommonDivisionofthe OverallProblem . 3-4
3-2 RF Radiated Susceptibility Limits . 3-5
vii
AMCP 706-235
LIST OF ILLUSTRATIONS (Continued)
Fig. No. Title Page
3-3 The Conductive Box Concept 3-5
4-1 TransmissionLoss'Tp.for a SolidMetal Shield Irradiatedbya Waveof377-ohm
Impedance 4-5
4-2 Absorption Lossfor Copper vsFrequency 4-8
4-3 Absorption LossA of Solid Magneticand Nonmagnetic Materials 4-9
4-4 Typical Shielded Compartment Discontinuities 4-11
4-5 ElectromagneticField ImpingingonaSolidMetal ShieldContainingaRectangu-
lar Hole 4-12
4-6 Panel Seam Configurations 4-15
4-7 Someofthe FactorsTo BeConsidered in Weapon System Packaging 4-18
4-8 Relative Shielding Effectiveness of Iron and Copper 4-19
4-9 XM511El Shipping and Storage Container.............................. 4-20
4-10 A MissileShowing the ImproperLocation ofSensitive Components 4-22
4-11 Shieldingby Using Bands of Foil 4-23
4-12 ZipperTubing...................................................... 4-24
4-13 CapacitanceofVarious Shielded Wires . ............................ 4-25
4-14 T-junction 4-26
4-15 RF-proofConnector 4-26
4-16 Connectorfor Shield Within a Shield 4-27
4-17 Typical Connectorfor Handling Shielded and Unshielded Wires 4-27
4-18 MethodofTerminating Shielded Cable Without a Connector 4-28
4-19 Insertion Lossvs Pressurefor Resilient Metal Gasket 4-29
4-20 Typical Mechanical Characteristicsofa Resilient Metallic Gasket 4-30
4-21 Gasket Compressibilityvs Scalability . . 4-33
4-22 Typical MountingMethods. . 4-34
4-23 Various Gasket Configurations 4-34
4-24 Fingerstock 4-36
4-25 Ballistic Case for LANCEWarhead Section 4-37
4-26 XM205 Adaption Kit Subassembly (Control Unit) 4-38
4-27 SealedInput Shaft Mechanism 4-39
4-28 Prevention ofRF Leakage at Removable Lid 440
4-29 An AcceptableRF ProtectiveUseofaCircularWaveguideinaPermanentAper-
ture for a Control Shaft 441
4-30 An AcceptableMethod ofShielding Panel-mounted Meters 441
4-31 MethodofMounting Wire Screen Over a Large Aperture 442
4-32 Typical Welded Screen Installation Over a Ventilation Aperture. .. 442
4-33 Typical Bolted Screen Installation Over a Ventilation Aperture . . 443
4-34 Honeycomb-typeVentilation Panel 443
4-35 Attenuation vsFrequency Curves for Various Screens 444
4-36 Attenuation vs FrequencyCurves for Various Screens and Honeycomb. 445
4-37 Attenuation-RectangularWavegide 447
4-38 Attenuation-CircularWaveguide 448
4-39 DifferentTypes ofWelded Joints 449
4-40 Influence ofScrew Spacing 4-50
4-41 Use of Nutand Bolt for Bonding...................................... 4-51
4-42 Military Standardfor Bonding Strap 4-52
4-43 Bonding Techniques (Direct vsIndirect) 4-53
4-44 Bonding Techniques (Solid Strap) 4-53
4-45 Impedanceofa Bonding Strap 4-54
vIII
AMCP 706·235
LIST OF ILLUSTRATIONS (Continued)
Fig. No. Title Page
4-46 ImproperBondingJumperInstallationShowing RestrictionofEquipmentMove-
ment . 4-54
4-47 Ground Return System for Metal Shielded Sensitive Component . 4-65
4-48 Fuze M525 . 4-66
4-49 Point-initiating, Base-detonating Fuze Having PiezoelectricCore Element . 4-66
4-50 Typical Interconnected Fuzing System . 4-69
4-51 Operation ofS&A Device . 4-70
4-52 Elimination ofPins-to-caseMode of Firing EED .•....................... 4-71
4-53 Properly Shielded Battery . 4-72
4-54 Battery With OpenTerminals . 4-73
4-55 Display ofTypes ofEED's . 4-77
4-56 Drawings Showing Construction of Typical EED's Usedin Army Missiles . 4-78
4-57 LaserActivated EED . 4-79
4-58 Drawing of Electric Match (Atlas Chemical Industries M-103) . 4-79
4-59 RF Firing Sensitivity of the Flare Northern 207D Squib (Bridgewire Mode)
Average Bridgewire Resistance0.18 ohm . 4-81
4-60 RF Firing Sensitivity of a Squib Sensitive to High Frequency Pulsed Power
(Bridgewire Mode) Average Bridgewire Resistance 1.20ohms . 4-82
4-61 RF Stimulus Applied in the Pins-to-case Mode .. 4-83
4-62 Drawing Showing ConstructionofCoaxial BED, Mark 7 Mod 0 . 4-84
4-63 RF Stimulus Applied Bridgewire-to-bridgewire Mode . 4-85
4-64 Ignition of Explosive Charge by Thermal Stacking of RF Pulse Energy . 4-86
4-65 A Weapon System in an RF Field . 4-96
4-66 Weapon System Circuit . 4-100
4-67 Power Reflected as a Ratio of Impedance . 4-101
4-68 Matching System for Worst Case Attenuation . 4-102
4-69 Insertion LossMeasuring System . 4-102
4-70 Classification ofProtective Devices . 4-104
4-71 Comparisonofthe WorstCaseAttenuationofaFerritePlug andaCarbonylIron
Plug . 4-105
4-72 M78 Detonatorin Its Holder . 4-107
4-73 RF Filterand Plug Assembly, M78E1 . 4-109
4-74 FerriteBeadAttenuator(Squib Switch) . 4-111
4-75 ConnectorWith Built-in RF Supressors . 4-112
4-76 Capacitor-ferrite Hybrid Filter . 4-113
4-77 WorstCase Attenuation of Ferrite Hybrids . 4-114
4-78 Inductor-ferrite Hybrid . 4-115
4-79 Assembly Drawingof2-pin Hybrid Filter (NASA) . 4-116
4-80 Worst Case Attenuation of Apollo Filter . 4-117
4-81 Army Developed Ferrite Attenuators . 4-118
4-82 Two Types of LCR Filters . 4-119
4-83 Comparison of Insertion Loss and Worst Case Attenuation of an LCR Filter . 4-120
4-84 Worst Case Attenuation of a Tantalum Feed-through Capacitor . 4-121
5-1 Bruceton Data Sheet . 5-3
5-2 Probit Estimate . 5-4
5-3 Basic Equipment Usedin Performing RF Sensitivity Tests ofan EED . 5-6
5-4 A Typical Shielding Gap Configuration . 5-10
5-5 Basic Antenna Model for a Shielding Gap . 5-10
5·6 Aperture of Loop as Shown in (A) at a Typical Terminal Board . 5-12
ix
AMCP 706-235
LIST OF ILLUSTRATIONS (Continued)
Fig. No. Title Page
5-7 Schematic Drawingof SystemTo BeAnalyzed . 5-13
5-8 Loop Approximation ofSystem Shown in Fig. 5-7 . 5-13
5-9 Antenna Configuration for Evaluation Derived from Fig. 5-7 . 5-13
5-10 Apertureof Loop Configuration at Paddle (Pin-to-pin Mode) . 5-14
5-11 Comparison of0.1% Firing Levelofthe EED With Maximum Power Pick-up 5-15
5-12 SPRINT MissileBeingIrradiated . 5-16
5-13 Radiation Environment Available at White Sands MissileRange . 5-17
5-14 Radiation Environment Available at Picatinny Arsenal . 5-18
5-15 DRAGON Missile Systemin Test . 5-20
5-16 Picatinny Arsenal RF HazardSimulation Chamber, 300kHzto 3MHz, (To Be
Extended Down to tokHz) 100Vim, 266mAim, 377ohms, 4,000ohms,or40
ohms (preliminary Checkout) . 5-22
5-17 EED InstrumentedWith a MicrominiatureThermocouple . 5-23
5-18 BlockDiagramof Crystal Diode Detectorand Instrumentation . 5-25
5-19 Diode DetectorMounted on a Detonator Plug . 5-26
5-20 Dual Bridgewire SVD . 5-27
5-21 Measured Response of SVD Comparedto Replaced EED . 5-28
5-22 Picatinny Arsenal Lightning Facility . 5-29
A-I GeometricRepresentation of aPracticalShieldingProblem .. . . . . . .. . .. . . .. A-2
A-2 Magnitude and PhaseAngleof tanh ('Y,t) for VariousValuesof
i',t Whenr.t =a,t(1 +j) . A4
=
A-3 ThicknessRequiredfor a,t 2 . A-5
A4 APracticalShieldingProblem . A-6
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AMCP 706·235
LIST OF TABLES
Table No. Title Page
2-1 Power vsFrequency for Nongovernment RF Sources . 2-2
2-2 RF Sources at a Typical Military Installation . 2-4
2-3 Triboelectric Series ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
2-4 Electric Fields Around Simple ChargeDistributions . 2-17
2-5 Inverse Surge Current-carryingAbility ofSilicon Protection Diodes . 2-47
2-6 Formulas for Calculation ofResistance to Ground . 2-49
2-7 Range ofResistivity Values for SeveralTypes ofSoils . 2-51
4-1 T Formulas . 4-4
p
4-2 Comparison ofTransmission Lossfor any Shield for the Common
Wave Impedances. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
4-3 Absorption Loss ofMetals at 150kHz . 4-7
4-4 Type ofSeamsin Order ofPreference . 4-16
4-~ Sensitivity for Various Spacer Materials(WaxGap Test) . 4-21
-4-~ Comparison of Shielded Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-24
4-7 Properties ofTypical Gasket Materials . 4-32
4-8 Characteristics ofConductive Gasketing Materials . 4-32
4-9 Electromotive Series . 4-55
4-10 GalvanicCouples . 4-57
4-11 FactorsInfluencingCorrosion in Solution . 4-58
4-12 Selection ofMetallicCoatings for Minimum Corrosion . 4-60
4-13 Specificationsfor Metallic Coatings . 4-61
4-14 Prevention of DissimilarMetalCorrosion . 4-62
4-15 BasicAerospace Ordnance Devices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-74
4-16 Types ofEED'sWithTypical InputCharacteristics . 4-76
4-17 List ofEED's Evaluated for Their RF Characteristics . 4-88
4-18 ComponentPart Failure Modesfor Electrical Components . 4-93
4-19 Typical IndicatorParameters . 4-95
4-20 Decibel-voltage, Current, and Power Ratio . 4-97
4-21 Ust ofEED's Available . 4-103
4-22 RF Protected M78 Detonator(Carbonyl Iron Plug) . 4-106
5-1 Comparison ofDetectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-21
6·1 Applicable Military Standards . 6-2
6-2 Applicable Military Specifications . 6-5
6-3 Other RFI/EMI Specifications . 6-7
6-4 Electrical Bond ClassesofApplication . 6-10
6-5 Current-carryingCapacity ofWiresand Cables . 6-11
6-6 System Voltages and Allowable Voltage Drops . 6-11
6-7 Environmental Levels . 6-14
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AMCP 706·235
LIST OFSYMBOLS
Symbol Quantity F = force
A = ampere of = degrees Fahrenheit
A = absorption loss;attenuation FET = field-effect transistor
Ae = effective aperture FM = frequency modulation
Aec = compositeeffective aperture f = frequency
Aem = maximum aperture fMH. = frequency in megahertz
AM = amplitude modulation ft = foot
AT= area G = conductance; antenna gain
AWG = American wire gage G = relative conductivity
8
a = semi-majoraxis of an ellipse GHz = gigahertz
ac = alternating current H = henry
:a,= unit radial vector H = magnetic field
B = magnetic flux density Hg = mercury
b = semi-minoraxis of an ellipse Hz = hertz
C = conservative loss parameter I = current
C = coulomb IL = insertion loss
Cap. = capacitance 1m"" = maximum current
CW = continuous wave t, = main stroke current
c = speed of light I. = surface current
D = displacement density; directivity i = surface current
d = distance in. = inch
d~ = electrode spacing J = joule
d = distance (height) j = unit imaginary number y':1.
ll
d. = distance from stroke where "K = degrees Kelvin
dE/dtmllX is determined kVA = kilovolt ampere
dB = decibel k = constant
de = direct current k. = constant (9 X 1O~
dE/dt = maximum rate ofchange of kA = kiloampere
mtIX
electric field kHz = kilohertz
E = electric field strength kV = kilovolt
E = electric field, vector kW = kilowatt
Em"" = maximum electric field kfi = kilohm
EED = electroexplosive device L = inductance
EMC = electromagnetic compatibility ,I = antenna length
EMI = electromagnetic interference /n = natural logarithm
EMP = electromagnetic pulse Ib = pound
EMR = electromagnetic radiation log = logarithm to the base ten
ERP = effective radiated power MHz = megahertz
e = constant (2.718...), base of m = meter
natural logarithms mil = one thousandth of an inch
e = eccentricity mJ = millijoule
F = farad MKS = meter-kilogram-second
xli
AMCP 706·235
MO = megohm V = volt
mm = millimeter Vm.... = maximum potential R,.
MOS = metal-oxide semiconductor p, = voltage drop across the
MOSFET = metal-oxide semiconductor ground resistance
field-effecttransistor v = velocity;speed
msec = millisecond W = power
mW = milliwatt W = watt
N = newton Wb = weber
n = number WMT = power transmitted through a
P = power solid metal
Pd = power arriving (delivered) at WT = power transmitted through a
input of RF supression device hole
P, = power that gets through system X = reactance
being protected X... = antenna reactance
PI = incident power ~ = system reactance
P, = reflected power XT = termination reactance
PR1 = rbeectewiveeendptroawnsemr wittiethroauntdshield Xxd == sdhieieleldctrtihcictkhnicekssness
receiver yd = yard
PR2 = receivedpower inside metallic Z = impedance
enclosure Zc = cable impedance
P = transmitter power ~ = small dipole radial wave
T
PD = power density impedance; input impedance of
PD = incident power density suppression device
I
PD. = shielded volume power density ZJU = impedance offiring unit
pli = picofarad ~ = small loop antenna radial wave
Q = charge; quality factor impedance; impedance of EED;
Q = figure ofmerit impedance associated with a
R
R = resistance; reflection loss measuring point
R... = antenna resistance Zo = characteristic impedance or free
R. = real part space impedance (377 0)
z"p =
R, = ground resistance impedance pin-to-pin
z"c
R = load resistance = impedance pins-to-case
L
R = mutual resistance Z. = shield impedance; combined
m
RR = radiation resistance impedance ofsystem being
R = termination resistance protected
Re(ZT) = real part of impedance Zw = waveimpedance
RF = radio frequency Z; = complex conjugate of Zw
RFI = radio frequency interference
GREEK LETTERS
r = radial distance; radius
rms = root-mean-square a = real part of attenuation
S.u = shielding effectiveness constant
SE = total shielding effectiveness 13 =imaginary part (phase constant)
SVD = stray voltage detector of propagation constant
sec = second 'Y = propagation constant of
T = temperature medium
TEM = transverse electromagnetic 'Y. = function of electrical parameter
Tc = transmission coefficient of a shield
Tp. = transmission loss E = permittivity
TV = television eo = freespace (air) permittivity
t = time; thickness of shield e.. = surrounding medium
t, = pulse rise time permittivity
V = voltage potential Ie = relative dielectric constant
xlii
AMCP 706·235
A = wavelength ,.,. = permeability; micro
,.,.A
9 = plane angle = microampere
""0
= free space (air) permeability
'11' = pi (3.14159...)
P = resistivity ,.,.R- = relative permeability
,.,.sec = microsecond
:lp ==power reflection coefficient ,.,.W = microwatt
(T conductivity n = ohm
T = time from leading edge offield Cl) = angular source frequency (2'11'f)
to time ofinterest; transmission • = degree (plane angle)
coefficient ·C = degrees Centigrade
xiv
AMCP 706·235
PREFACE
The Engineering Design Handbook Series of the Army Materiel Command is a
coordinated series of handbooks containing basic information and fundamental data
useful in the designand developmentof Army materiel and systems. The handbooks
areauthoritativereferencebooksofpracticalinformationandquantitativefactshelpful
in the design and development of Army materiel. The purpose of this particular
handbookistotakethe wealth ofinformationaccumulatedbythe Armyoveraperiod
ofyears on the subject ofhardening weapon systems against RFenergy and to make
thisinformationavailabletothedesigner.Muchofthedatainthishandbookisinchart
ortableformforrapidretrieval. Also,referencesaregiventhatspecifywherethesedata
were obtained.
Althoughthis handbookwaspreparedforthedesigner ofweapon systemsitshould
also be of benefit to those engaged in designing test programs for determining the
hardeningofweaponsystems.Chapter5presentsthelatestprogrammingconceptsthat
the Army is now using.
This handbook was prepared by the The Franklin Institute, Philadelphia, Pa., for
the Engineering HandbookOfficeofDukeUniversity, prime contractorto the Army
MaterielCommand, with Mr. Roy Wood asthe principalauthor. Technicalguidance
and coordination were provided by a committeewith representatives from Picatinny
Arsenal, The U.S. Army Electronics Command, Redstone Arsenal, Harry Diamond
Laboratories, and White Sands MissileRange. Members of this committee were Mr.
Daniel Carella, Chairman, Mr. Edward Ramos, Mr. Francis Wilhelm, and Mr. D.
Roger Wight.
TheEngineeringDesignHandbooksfallinto two basiccategories,those approvedfor
releaseand sale,and those classifiedfor security reasons.TheArmyMaterielCommand
.policyisto releasetheseEngineeringDesignHandbooksto other000activitiesandtheir
contractors and other Governmentagencies inaccordancewithcurrent ArmyRegulation
70-31, dated 9 September 1966. Itwill be noted that the majority of these Handbooks
canbe obtained from the NationalTechnicalInformation Service(NTIS).Proceduresfor
acquiringtheseHandbooksfollow:
xv