Nội dung text 23 Virtual Work Method on Trusses.pdf
PSAD 23: Virtual Work Method on Trusses To solve for the deflection of a joint in a truss, the general formula is used: δ = ∑ SuL AE Here, S is the internal force of each member based on the external loads. u is the internal force of each member given when a unit force is applied on a joint where the direction of the unit load is of the same direction as the direction of the deflection being calculated. A is the cross- sectional area of each member. E is the modulus of elasticity. I is the moment of inertia. • Example: Find the vertical and horizontal deflection for point B. Here, A = 1000 mm2 , E = 200 GPa. Unit vertical load at B