1、_ -=:-= Reproduced By GLOBAL - . _ ENGINHRING DOCUMENTS With The Permission Of SAE =- Under Royalty AVeement LIGHTNING TEST WAVEFORMS AND TECHNIQUES FOR AEROSPACE VEHICLES AND HARDWARE Report of SAE Committaa AE4L 20.1978 Users of this document should ascertain that they are in possesion of the late
2、st version . This version supersedes SA! Special Task F Report “Lightning Test Waveforms and Techniques for Aero space Vehiclesand Hardware“ dated Hay 5,1976. LIGHTNING TEST WAVEFORMS AND TECHNIQUES FOR AEROSPACE VEHICLES AND HARDWARE TABLE OF CONTENTS Section 1.0 2.0 3.0 4.0 INTRODUCTION . . . . .
3、. . . . . . . . . . . . . LIGHTNING STRIKE PHENOMENA . . . . . . . . . . . 2.1 2.2 2.3 Natural Lightning Strike Electrical 2.1.1 Prestrike Phase 2.1.2 High Peak Current Phase 2.1.3 Continuing Cuent 2.1.4 Restrike Phase Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . Aerospace
4、 Vehicle Lightning Strike Phenomena 2.2.1 Initial Attachment 2.2.2 Swept Stroke Phenomenon 2.2.3 Lightning Attachment Zones Aeospace Vehicle Lightning Effects Phenomena 2.3.1 Direct Effects 2.3.2 Indirect Effects 2.3.3 Effects on Personnel STANDARD LIGHTNING PARAMETER SIMULATION 3.1 3.2 3.3 Putpose
5、Waveform Descriptions for Qualification, Testing 3.2.1 Voltage Waveforms 3.2.2 Current Waveforms Waveform Description for Engineerina Tests 3.3.1 Purpose . 3.3.2 Voltage Waveforms 3.3.3 Current Waveforms TST TECHNIQUES 4.1 Qualification Tests 4.1.1 Full Size Hardware Attachment Point 4.1.2 4.1.3 4.1
6、.4 4.1.5 4.1.6 Tests - Zone 1 . . . . . . . . . . . . . . Direct Effects - Structural Direct Effects - Combustible Vapor Ignition Via Skin or Compnent Puncture, Hot Spots or Arcing Direct Effects -Streamers Direct Effects -External Electrical Hardware Indirect Effects -External Electrical Hardware i
7、 2 2 2 2 4 4 4 4 4 5 5 6 6 7 7 7 7 8 9 9 9 9 13 13 13 15 16 16 17 4.2 Engineering Tests . . . . 18 4.2.1 Model Aircraft Lightning Attachment Point Test 18 4.2.2 Full-Size Hardware Attachment Point Test ;- Zone 2 . . 18 4.2.3 Indirect Effects - Complete Vehicle 20 ii -1.0 Il1ltCDtlCTION This docuaent
8、 presents t.st wavefotn8 aDd tech niqu for s1malated 11ghtDiDg test1Dg of aerospace vehicl.s and hardware. :he wav.forms pr.ated are baaed OIl the beat available lmmrledg. of the natural lightning 4lllvirom:leDt coupled with a practical COD sideration of state-of-the-art laboratory t.chniques. !his
9、cloc_t does DOt 1Dclud. d ip criteria nor does it specify vh1ch items should or should DOt be tested. Tast. aDd aaaociated procedur de.cribed hare in are divided iDto two Reneral categori : o Qualification tests o Engineer1Dg teats Accsptable levals of d . aDd/or pa._faU criteria for the qualificati
10、on t ts mu.t be provided by the cogn1 iD .uch iD .cances. application of tbe wav.form CDIIIPODaDts llluat be tailored to the spacific .ituation. The test waveforms aDd t.chniqu de.cribed bereiD for qualification test. s1mulate tl. effects of a savere lightDiDg strike to au aerospace vehicle. Where i
11、t bas been shown that t t coad1tioaa can af fect results of the t t, a specific approach 1. . . I . .“:. 10 ms Time (Not to Scale) (B) lwderate positive lightning flash current waveform. Figure 2-2 Lightning flash current waveforms. 3 2.1.4 Restrike Phase In a typical lichtning-flash there will be s
12、ev eral high current strokes followinC the first return stroke. !hese occur at intervala of several tens of milliseconds as different charlile pocl:ets in the cloud are tapped and their charge fed into the lightning channel. Typically the peak amplitude of the re strikes is about one half that of th
13、e initial higb current peak. but the rate of current rise is often greater than that of the first return stroke. The continuing current often linke tUR vsrious success ive return strokes. or restrikes. 2.2 Aerospace Vehicle L1.ghtniDa Strike Ph_ 2.2.1 Initial Attachment Initially the lightning flash
14、 will enter and exit the aircraft at two or IIIOre attachment points. There will always be at l . t one entrance po1Dt aad ooe ait pe1Dt. It 18 not possible for tha vehicle to store the electrical energy of the lightning flash 1D the capaci tive field of the vehicle and so avoid an exit po1Dt. Typic
15、ally thue initial attachment points are at the IIXtrl!Clities of the vehicle. These 1Dclude the nose. wing tips. elevator and stabilizer tips. protrud1Dg antennas. and angine pods or propeller blades. Light niDg can alae at tach to the leading edge of swept wings and sane control surfaces. 2.2.2 Swe
16、pt Stroke Phenomenon The l1ghtD1ng channel is -mat atat:I.Dnary in space while it is transferr1ng electrical charge. When a vehicle 18 1nvolved it becomu part of the channel. However. due to the speed of the vehicle and the length of time that the lightning chaDDel ex ists. the vehicle caD lIIOVe re
17、lative to the lightn1Dg channel. When a forward 8Xtrem:l.I;y. auch a _ or wing lIIOunted a1111De poda are 1Dvolved. the aurface !loves through the lightning channel. TIIU9 the light ninl; channel appears o Sleep acv. over the 3uriace ao illuBtrateu ill Figurc 2-1. 7:1is is known as the. SHopt stroke
18、 phenoDenon. Aa the sweepinr, action oc curs. the type of surface can cause the lightning ChalUlel attach po1nt to dwell at various surface lo cations for difforont perioda of ti,n, resultin in a sjippin:; action uhich produces a serios of dis creto attaclll1ent points alom; the sweeping lath. The .
19、mount of d3l3ago produced at /lny point on the aircraft by a swept-stroke depends upon the type of naterial. the arc dwell te at that point, and the li!lhtning currents uhich flow during the attach ment. Both high peak cunent restrikes with inter mediate current camponents and cont1nuing currents ma
20、y be experienced. Restrikes typically produce re aetaehDene of the arc at a new poine. lo/hon the ligheniDg arc has been swept back to one of the trail1Dg edges it may rl!Clain attached at that point for the remaining duration of the light ning flash. An initial exit point, if 1t occurs at a trailin
21、g edge, of course. would not be subjected to any swept stroke action. The significance of the swept stroke phenonenon 18 that portions of the vehicle ehat wuld not be targets for the i1Utial entry and exit point of a lhtn1ng flash _y also be 1Dvolved in the light n1n suffi cient to call.e malin . of
22、 haDd. or f t and ._ d18Orientation or confu.ion. Th1a can be quite baa ardous in h1gh-perfo1:lllb1a dot. 3.0 STAlIDAlU) LIClmrtr: PAIWc:TElt snruLATIOll 3.1 llarpose CoDplec:e natural lightning flashes C8“Iot be du plicaC:ed in the laboratory. llDst of the voltage and current characteristics of lig
23、htning, however, can be duplicated separately by laboratory generators. :hese characteristics Are of two broad categories: The VOLTAGES produced during the lielltning flash and the cmumrrrs that 1_ in the cCllllpleted lightning cha_l. .ith a few exceptions, it is not neeessary to siDll late high-vol
24、tace and higb-current characterisc:lcs together. The high-voltage c:baracteriatics of lightning dotermine attachment points, breakdown patha, and Btoamer effects, whereas the current characteristics detem1ne direct aud indirect effects. In I:IDst casea, light1l1ng voltagea are a1mulated by high-impe
25、dance voltage generators operating into high-1npedance loads, whUe lightning currents are simulated by l_:Lmpedance current generators operat ing into 1mpedance loads. The lIavefoma described in this section are ide alized. Definit10ns relating to actual waveshapes are covered in ANSI and IEEE Stand
26、ard lec!udques for Dielectric Teats. ANSI C68.1 (1968) aDd IEEE :fa. 4. nl e specificat10na are equivalent and are in tum equivalent to HiGh Voltage Test Tee!m1gues, me 60-2 (1973). :he definitions in thue doclllleuts should be ueed to determine the front t1lle, duration and rate of riae of actual w
27、veforms. Severe lightning flash voltage and current wave forms, described in Paragraph 3.2 have been de veloped for purpos of qualification t.sting: wave foma in Paragraph 3.3 are for R) flowing for a oax:1J:nm duration of 5 a1lll8econds and a oaxi mum charge transfer of 10 coulcmbs. The wavefom sho
28、uld be unidirectional, e.g. rectangular, exponen tial or linearly decaying. 3.2.2.3 Conponent C - Continuing Current Component C aimulates the continuing current that 1O1s during the lightninS fla.h and transfers nost of tbe alectrical cllarga. !hia ccmponent !:IUBt trans fer a charge of 200 coulcmb
29、a :t20I) in a t1ae of be tween 0.25 aDd 1 _cmd. Th1a implias current ampli tudes of betveea 200 and 800 amperes. The waveform should be unidirectional. e.g. rectangular, exponen tial or l1uarly decaying. 3.2.2.4 Caeponeat D - Reatrike Current C-ponent j) aimulatea a subaequent l11gh peak currllDt. I
30、t 1:Out llaveforms G1 and G., - DmDped Osclllatory IIsveforms -Pnat rata of rl8e current waveforms and higher amplitude wavefoms may often be uaefully enployed for indirect affects testing. For indirect effecta de pendent upon resistive or diffusion flux effects (i.e. not aperture couplinG) a low fr
31、equency oscillatory current - waveform Cp in ,4h:ich the period (11 f) 18 10ng coapared tdth tlie dUfus:ion time, should be uaed. This requ:1res a frequency, f, of 2.S k1lohertz or lower (i.e. the duration of each half-eycle 18 equal to or greater than 200 1“1). Where res:istive or diff usion effect
32、s are _urad, the scal1D8 should be in terms of the peak current, with full scale being 200 leA. Por indirect effects dependent upon aperture coupling the high frequency current, waveform C2 should be used. The lIIIXimum frequency of ,.“eorm G2 should be no h:igher than approx1Jnately 30n Khz or 1/10
33、 of the lowest natural reSOaaDt frequency of the air erafth:etuzu circuit, whichever :is lower. tntere apar ture-coupled effscts are measured the scaUng should be in terms of rate-of-rl8e (di/dt), v:1th full scale be1Dg 100 kA/pa. When tutine composite structures v:1th waveform G2, resl8tive aad dif
34、fusion nux induced voltag _y occur as well as aperture coupled voltages, and re sults should be scaled both to 200 leA and to 100 kA/pa. 10 w . “ u CI! o . i t: a :OLTAr.:. IAVr.Fnr:l “ Flashover OLTAf;r HAVJ:FOR! R crest amplitude I) o 1.2 )Is 20% 50 )1S 20% TfJlle (Not to Scale) Figure 3-2 Idealiz
35、ed High-voltage tut waveforms for qualification testing. CURRF.!ft CrttPOIENT A (Initial troke) Definition of rate of rise require lIIent of teat waveform E. Peak amplitude - 200kA + 10: Action.Intep,ral -2xll) seconds + 21) current T1lIe nuration -:s 50Qls CURREIlT COI-t!OlmNT R (Intermediate Curre
36、nt) CharRe Transfer- 10 CoulOlllbs Atlpl1tucle- 2kA 11)% /RRENT CafPOENT C (Continui Current) Charlie “1ransfer 2QO CoulOlllbs + 21)% Anpl1tllde - 200- 800A T1ae (Not to Scale) CURRENr CrtPONENT 0 (Restrike) Puk :; o TI T2 Tme (Not to Scale) c = u I 7 Wavefor. GI S 2.5 kHz (llee Para. 3.3.3.2) Wavef
37、or. G2 300 kHz (se. Para. 3.3.3.2) Figure 3-5 Idealized current wavefo1I for enineerinR tellts. (Sote: Peak aIIIpl1tud.s are nnt the “lillie.) l2 Table 1 Application of aveforms for Qualification Tests Test Pull size hardware attachment point Direct effects -structural “ “ “ II Direct effects -cOlll
38、bustible valOr ignition Direct effects -.trlUllllers Indirect effecta -ezternal electrical hardware Zone 1A lB 2A 2B 3 Voltage waveforas A R x Current llaveforms/Components DAB C D F. x x x x x x x x x x x x x x Same current components as for structural tests x x3 Note 1. lIlIe IIveragp. current Clf
39、 2 kA + 10% for a dwell tillp. lells than 5 1II1lliseconds “,“ured 1n T;st 4.2.2 tip to a max1t1111111 of 5 r.llll1seeonds Note 2. Use Averar,p- current of 400 alllp for dwell t1me 1n eeesll of 5 “sec aa dete1tll1ned by enp,ineer1n tests. lote 3. Indirec effec:t. shoud alao bl! measured with current
40、 cOr.tlonents A, B, C, n aa a,ropriate to the taat ZOQineering test. setup and measurl!llent details and data requireRents are described in. the following para graphs. 4.1 qualification Tests 4.1.1 Pull SiZe !lardware Attachment Point Tests -:0118 1 4.1.1.1 Objective Tllis attachment point test will
41、 be conducted on full size structures that include dielectric surfaces to determine the detailed attac:hment points on the ex ternal surface, and if the surface is noametallic, the path taken by the lightning arc in reaching a metallic structure. . 4.1.1.2 waveforms Test voltage waveform A should be
42、 applied between the electrode and the grounded test object. In the case of test objects havinR particularly vulnerable or fliRht critical ca.ponents it _y be adVisable to repeat the teats uetag waveform D aa a confirutory test. 4.1.1.3 Teat Setup The teat object should be a full-scale produc tion l
43、ine hardware component or a representative pr_ totype. since lII1nor changes frOID design samples or prototyp _y change the lightning test reaults. All conducting objects uithin or on l101IIIIetallic bard ware that are normally connected to the vehicle when inatallad in the aircraft should be electr
44、ically coo nected to ground (the return side of the lightning generator) Surrounding external metallic vehicle structU1:e should be s1mulated and attached to the teat object to make the entire test object look as IIIIICh lib the actual vehicle region uDder teat sa possible. The teat electrode to whi
45、eh test wltage is ap plied should be positioned so that its tip is 1 meter away from the nearest surfaee of the test object. Dinenaions of the tut electrode are not critical. Generally. !:lOde! tests or field experience will have ind1cated that lightning flashes can approach the ob ject under test f
46、rom several different directions. If so, the teats should be repeated with the hieh voltage eleetrode oriented to create strokes to the object from these different directions. 14 If the test object is so small thst a l-meter sap remits strokes to miss the test object, or if a l-meter gap is inapprop
47、riate for other reasons, shorter or longer gaps l:I8y be uaed. :Iultiple flash overs should be applied from each electrode position. Tests nay be commenced with either positive or nega tive polarity. If test electrode positiOns are found frOD llhich the simulated lightning flashovers do not contact the test piece. or do not
