Horizontal link 2 is pinned to the vertical wall at A and pinned to link 3 at B. The opposite end of link 3 is pinned to the wall at C. A vertical force, P = 25 kN is acting on link 2 at B.

Link 2 has a 20 mm-by-30 mm solid rectangular cross section, and link 3 has a 40 mm-by-40 mm solid square cross section. The length of link 3 is BC = 1.2 m, and ∠ABC = 30◦. The two links are made from a steel alloy with tensile yield strength Syt = 190 MPa, compressive yield strength Syc = 205 MPa, and modulus of elasticity E = 207 GPa. Using the theoretic value for the end-condition constant for link 3, determine: (a)

the value of the slenderness ratio at the point of tangency between the Euler column formula and the Johnson parabolic formula;

(b) the critical load and the factor of safety guarding against buckling of link 3; and

(c) the minimum width of the square cross section of link 3 for the factor of safety to guard against buckling to be N = 1.

Figure P11.44 Simple truss.