Structure CAD ”

       


, .. f = f(t), , dZ/dt d2Z/dt2 .

J(t) = M(d2Z/dt2) (19.11)

, ,

M(d2Z/dt2) + KZ(t) = f(t). (19.12)

, , ( ).

( ) ,

Z(t) = Ysin(wt + j). (19.13)

(19.13) Y ( ), w , j . (19.13) (19.12) , f(t) = 0

(K - w2M) Y= 0, (19.14)

, wi (i = 1,...,n), , (K - w2M). Yi


筮 ந쭮 ⥫. ⥫ 祭 ⠪ ࠧ, ᨬ쭠 Yi ࠢ . ⠪ ⬥ ᢮⢮ ⮣쭮 ᮡ⢥ ஢ ⭮⥫쭮 , ⠪ ⭮⥫쭮 ⪮, ..

YiÒMYj= 0 è YiÒKYj= 0 ïðè i ¹ j. (19.15)



᪮ ᫮ Z, 묨 易 樮 ᨫ (⢮ ᪨ ⥯ ᢮), 뢠 訬, 祬 ᪮ . ਬ஬ 㦨 㧫, 筮 뢠騥 ⥫쭮 襥 ᪮ ﭨ, 祬 ᬥ饭. SCAD 樮 , ᮮ⢥騥 ⠬ 㧫 㣨 樮 ࠪ⨪ ந஢, 㦥 ᠬ 짮⥫, 㫨 ᪮ . ᫨ 樮 ⠢ 㧪 뢠, ࠧ Y YO, ண ᨫ 樨 ࠢ , YI, 易 樮묨 ᨫ, ⥬ (19.14) ଥ

KOO YO + KOI YI = 0;

KIO YO + KII YI = w2MII . (19.16)

⮩ ⥬ ᪫砥 YO १ 㪠 楤 "᪮ 㯫⭥" ࠧ୮ 쭮 १ 㬥蠥 ਮ⠥

(KOO-1 MII - l2 I) YI = 0, (19.17)

I - 筠 , l = 1/w.



⢥ १⮢ 쭮 SCAD 뤠 ᮡ⢥ ᫠ li ᮡ⢥ YI (19.17). 易 㣮 w = 1/l (ࠤ/ᥪ), 横᪠ q = w/2p () ਮ = 1/q.

ᨫ ⮣쭮 ᮡ⢥ 襭  ᪮ ࠧ

Z(t) =
(t)Yi (19.18)

ᯠ ⥬ ७樠 ࠢ (19.12) ᨬ ⭮⥫쭮 饭 न yi(t). ࠢ ⮬ ய樮쭮 ᪮ ⥫쭮 童, ண 뢠 ᮯ⨢ ,

d2 yi /dt2 + 2xi dyi /dt +wi2 yi = Pi(t)/Mi. (19.19)

饭 ᨫ

Pi(t) = w2 YTi f(t), (19.20)



Mi =
MYi (19.21)

ࠬ 堭 xi , ᮢ⭮ 砫묨 ᫮ﬨ yoi y1i , 砥묨 Zo = Z(0)

Z1 = dZ(0)/dt 㫠

yoi =
MZo , y1i =
MZ1 (19.22)

। 襭 . 襭 ࠦ

yi = exp[-xi wi t] {[(yoi xi wi + y1i)/ wDi] sinwDit + yoi} +

+ (1/wDiMi)
exp[-xi wi (t - t)] sinwDi(t - t)dt , (19.23)



஬ ࢮ ᫠ 뢠 砫 ᫮, ஥ ⥣ࠫ .

室 ࠦ (19.23) ஢

wDi = wi (1 - xI2)1/2 (19.24)

⫨砥 wi 祭 䬨᪮ ६

d = 2pxw/wD > 2px. (19.25)

19.3. 襭 ⥬ ࠢ

᫥ ⮣, ।⠢ 筮⭮ , । ६饭 㧫 ᢮ 襭 ⥬ ࠨ᪨ ࠢ

KZ=F, (19.26)

: K - ᨬ筠 ⥫쭮 । ࠧ஬ N´N; F - ࠢ ⥩ (㦥) ࠧ஬ N´k (k - ⢮ 㦥); Z - ᪮ ६饭 ࠧ஬ k´N.

᪮ 設⢥ 砥 K  ࠧ०, 㬥襭 ॡ㥬 ⨢ , 譥 ६ ।⥫쭮 ந ७㬥 ⥬ (19.26) 楫 樨 䨫 (.19.2).



.19.2



SCAD ॠ ᪮쪮 ⮤ ७㬥樨, , 娫-, ⮤-䠪 ॢ쥢, ⮤ x 祭 ࠫ 祭. ᠭ ⮤ ࠢ⥫쭠 ࠪ⨪ ਢ ᯥ樠쭮 . 짮⥫ ।⠢ 롮 ⮤ ७㬥樨. 㬮砭 ᯮ 娫-, .. ⮣ ⮤ ⨢ . ४樨 롮 ⮤ ७㬥樨, .. 䥪⨢ ⮣ ⬠ ⥫쭮 ⭮ .



襭 ⥬ (19.26) ।⥫쭮 ந 㣮쭮 ࠧ ஢ ⮤ 롮஬ ࠧ饣 浪 ᫥ ७㬥஢ .

᫨ 㣮쭮 ࠧ K ࠧ ⮢ ࠢ , .. ᭨, K - ஦, ᢨ⥫ ᪮ 塞 ⥬, ந ⮬᪮ ⥫쭮 殮 裡, ॢ饩 ⥬ 塞. ⮬ 짮⥫ ।⠢ ଠ 㧫 ⨯ ⥯ ᢮, ந 痢. ⨬, ஦ 筮 ࠢ ࠧ饣 ,  ᫠ "ࠪ᪨ ࠢ " 롮 ⮣ ண (ࠬ 筮 襭)  ࠬ஢, 짮⥫ ᯮ廊 ᠬ.

ᮮ饭 ⠭ ⥫ 痢  ⮪ 襭 , ४㥬 ⥫쭮 ஠஢ 奬 ᭨ 稭 ந宦 ᪮ 塞 樨. ᭮ 㣨 祭 ࠬ 筮 襭.

⥫ ࢨ ।⢮  ஫ 襭 ⥬ (19.26).  ᮮ饭 让 稭 訡 襭, ஥, ࠢ,  ᫥⢨ 宩 ᫮ K, ᫥ ⥫쭮 ஠஢ ६饭 㧫 㡥 ⮬, 祭 襭  ਥ ୮ 窨 ७. ᫮ ᥣ 易 㤠筮 樥 뢠 ⥬ (ਬ, 砩 " 塞" ⥬) 㤠筮 樥.