written 5.7 years ago by | modified 2.7 years ago by |
Using virtual work method, for rigid jointed frame as shown in fig. Find horizontal displacement of roller. Take $E=200\times 10^3MPa,I=4\times 10^6mm^4$
written 5.7 years ago by | modified 2.7 years ago by |
Using virtual work method, for rigid jointed frame as shown in fig. Find horizontal displacement of roller. Take $E=200\times 10^3MPa,I=4\times 10^6mm^4$
written 5.7 years ago by |
$\sum M_A=0$
$(-V_d\times 4)+(15\times 4\times 2)(8\times 5)=0$
$\therefore V_d=40kN$
$\sum F_y=0$
$V_A+40-60=0$
$V_a=20kN$
$\sum M_A=0$
$-V_d\times+(1\times 2)=0$
$4V_d=2$
$V_d=0.5kN(\uparrow)$
$V_a=0.5kN(\downarrow)$
$E=200\times 10^3MPa$
$=\frac{200\times 10^3\times 10^{-3}kN}{(10^{-6})m^2}$
$E=200\times 10^6kN/m^2$
$I=4\times 10^8mm^4=4\times 10^8\times (10^{-3})^4m^4$
$I=4\times 10^{-4}m^4$
Part | Origin | Limit | $M_u$ | $m_u$ | EI |
---|---|---|---|---|---|
AB | A | 0-5 | 8.x | 1.x | EI |
BC | B | 0-4 | $20x+40-7.5x^2$ | $(1\times 5)-(0.5x)$ | EI |
CD | C | 0-3 | 0 | 1.x | EI |
$\therefore \Delta _{DH}=\int _0^L \frac{M_u.m_u}{EI}dx$
$=\frac{1}{EI}[\int _0^5(8x)(x)dx+ \int _0^4(20x+40-7.5x^2)(5-0.5x)dx]$
$=\frac{1}{EI}=[\int _0^5 8x^2dx+\int +0^4 (100x-10x+200-20x-37.5x^2+3.75x^3dx)]$
$=\frac{1}{EI}[\int _0^5 8x^2dx + \int _0^4 (70x-37.5x^2+3.75x^3+200)dx]$
$=\frac{1}{EI}[(\frac{8x^3}{3})_0^5+(\frac{70x^2}{2}-\frac{37.5x^3}{3}+\frac{3.75x^4}{4}+200x)_0^4]$
$\therefore \Delta _{DH}=\frac{1133.33}{EI}$
$=\frac{1133.33}{200\times 10^6\times 4\times 10^-4}$
$=0.01416 m$
$\Delta _{DH}=y_D=14.166mm$