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Veza naprezanja i deformacija

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τ<br />

τ<br />

τ<br />

xy<br />

yz<br />

zx<br />

= Gγ<br />

= Gγ<br />

= Gγ<br />

xy<br />

yz<br />

zx<br />

Tenzor <strong>naprezanja</strong> je:<br />

(b) modul kompresije<br />

3<br />

3<br />

3<br />

<strong>Veza</strong> izmeñu <strong>naprezanja</strong> i <strong>deformacija</strong> - 21 -<br />

−4<br />

= 80.<br />

77 ⋅10<br />

⋅ 2⋅<br />

0.<br />

3⋅10<br />

−4<br />

= 80.<br />

77 ⋅10<br />

⋅ 2⋅<br />

0.<br />

8⋅10<br />

−4<br />

= 80.<br />

77 ⋅10<br />

⋅ 2⋅<br />

( −0.<br />

5)<br />

⋅10<br />

=<br />

4.<br />

86<br />

MPa<br />

= −8.<br />

46 MPa<br />

= 12.<br />

9 MPa<br />

[ σ ] =<br />

⎢<br />

4.<br />

86 77.<br />

7 −8.<br />

16<br />

⎥<br />

MPa<br />

ij<br />

⎡58.<br />

5<br />

⎢<br />

⎢⎣<br />

12.<br />

9<br />

4.<br />

86<br />

−8.<br />

16<br />

Modul kompresije odreñen je izrazom iz tablice 4.1:<br />

PRIMJER 4.2<br />

12.<br />

9<br />

58.<br />

48<br />

E 210<br />

K = =<br />

= 175 GPa<br />

3<br />

( 1−<br />

2ν)<br />

3(<br />

1−<br />

2⋅<br />

0.<br />

3)<br />

Stanje <strong>naprezanja</strong> u točki zadano je tenzorom <strong>naprezanja</strong>:<br />

Tijelo je zagrijano za ΔT = 20 o C.<br />

80<br />

⎤<br />

⎥<br />

⎥⎦<br />

[ σ ] =<br />

⎢<br />

− 60 30 20<br />

⎥<br />

MPa<br />

ij<br />

⎡<br />

⎢<br />

⎢⎣<br />

− 40<br />

− 60<br />

Zadano je: E = 210 GPa, ν = 0.3; α = 1.2 . 10 -5 1/ o C<br />

Napisati tenzor deformacije.<br />

20<br />

− 40⎤<br />

⎥<br />

50⎥⎦

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