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Galīgo elementu metode

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68 NODAĻA 4. DIVDIMENSIJU PROBLĒMAS<br />

T y<br />

2<br />

q 3<br />

T x<br />

q 4<br />

q 5<br />

q 6<br />

c 12<br />

q 2<br />

y<br />

3<br />

1<br />

q 1<br />

x<br />

Zīmējums 4.8: Virsmas spēki<br />

Apskatīsim gadījumu, kaduz malu c 12 darbojas virsmas spēki T x ,T y .Tad<br />

∫<br />

u T T tdc =<br />

C<br />

∫<br />

(uT x + vT y )tdc<br />

c 12<br />

(4.49)<br />

Izmantojot formulu(4.16), iegūstam<br />

∫<br />

u<br />

∫c T T tdc = q 1<br />

(tT x N 1 dc<br />

12<br />

( ∫ ) ∫<br />

+q 3 tT x N 2 dc + q 4<br />

(tT y<br />

)<br />

+ q 2<br />

(tT y<br />

∫<br />

)<br />

N 2 dc<br />

)<br />

N 1 dc<br />

(4.50)<br />

Ir jāatzīmē, ka N 3 = 0 gar malu 1-2 un N 1 + N 2 =1. Visuintegrāļu vērtība<br />

formulā (4.50) ir<br />

∫<br />

kur<br />

c 12<br />

N i dc = 1 2 c 12<br />

c 12 = √ (x 2 − x 1 ) 2 +(y 2 − y 1 ) 2<br />

un (4.50) var izskaitļot<br />

∫<br />

u T T tdc = q T T e (4.51)<br />

C<br />

kur<br />

q T =[q 1 ,q 2 ,q 3 ,q 4 , 0, 0]

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