olans

PROBLEM $2$ The truss structure shown in figure is loaded with a downward load $(P=10kN.$ The cross$-$sectional area of bars is $4{10}^{-4}{m}^2.$ Elasticity Modulus of bars is $70$ GPa $(70{10}^9$ Pascal$).$

a$.$ Assemble the element stiffness matrices

b$.$ Assemble the global stiffness matrix

c$.$ Find unknown displacements $U_5$ and $U_6$

d$.$ Find element stresses and say whether they are compressive or tomils

$[K^{(e)}]=k_e\left[\begin{array}{cccc}{c}^2& sc& -c^2& -sc\\ sc& s^2& -sc& -s^2\\ -c^2& -sc& c^2& sc\\ -sc& -s^2& sc& s^2\end{array}\right]$