GRAEVINSKI FAKULTETSVEUILITA U MOSTARUPredmet: MEHANIKA 2Vjebe br. 11Profesor: doc dr sc Mladen Koul Profesor: doc. dr. sc. Mladen KoulAsistent: Ante Dolan, mag. ing. gra.1Mostar, 13. sijenja 2014.PRINCIP VIRTUALNOG RADAZADATAK 1 ZADATAK 1.Za statiki sustav prikazan na slici odrediti reakcije oslonaca primjenommetode virtualnog rada, te skicirati dijagrame presjenih sila. g , j g p j2RJEENJE:ArR r P2 2r P 10 A Ar P 10R r P R2 2 2 AR 5kN 3r BrM F 02 r4 Br rM F 04 2 Br rM F4 2 BM 2F 220 40kNm 4BX r F r 0 BX r F r BX F 20kN 5BrY r P 02 BrY r P2 2P 10BP 10Y 5kN2 2 67ZADATAK 2.Za statiki sustav prikazana na slici odrediti reakcije oslonaca koritenjemp j jnaela virtualnog rada.8RJEENJE:r : 4 x : 2,5 x 0, 625 r Y 0 625 20 i 60 M 0 BY 0, 625 r 20sin60 r M 0 r4 4BrY 0, 625 r 20sin60 r M 04 r 5 9Br 520sin60 r M 20sin604 4Y 25, 71kN0, 625 r 0, 625 AX r 10 r 20cos60 r 0 AX r 10 r 20cos60 r X 10 20cos60 20kN 10AX 10 20cos60 20kN r : 2, 5 x :1, 5 x 0, 6 r r rr 2, 52,5 Y r 6 r 20sin60 0 6 r 5 0 AY r 6 r 20sin60 0, 6 r 5 0 AY 2, 5 62, 5 20sin60 0, 62, 5 5 62 5 20sin60 0 62 5 5 11A62, 5 20sin60 0, 62,5 5Y 2,39kN2, 5 3, 5cos 23, 273 81 3,812, 5cos x 2, 72x x3 81 2 72 0 714 A 1 1 1 2 2 2M 10 1,5 63 5 20sin60 1,5 20cos60 1, 07 0 1 2 1 23,81 2, 72 0, 714 A 2 2 2 2 2 2M 0, 714 150, 714 180, 714 5 25,98 10, 7 12AM 18, 60kNm OSCILACIJE1314151617181920