The horizontal link 2 is subjected to the inclined load F = 8 000 N at C as shown. The link is supported by a solid circular cross section link 3 whose length L3 = BD = 5 m. End D of vertical link 3 is fixed in the ground link, and end B supports link 2 (that is, the effective length of the link is Leff = 0.5 L3). Link 3 is steel with a compressive yield strength Syc = 370 MPa and a modulus of elasticity E = 207 GPa. Determine the diameter,

d, of link 3 to ensure that the factor of safety guarding against buckling is N = 2.5. Also, answer the following statements true or false and briefly give your reasons.

(a) The slenderness ratio at the point of tangency between Euler’s column formula and Johnson’s parabolic equation does not depend on the geometry of the column.

(b) Under the same loading conditions, a link with pinned-pinned ends gives a higher factor of safety against buckling than an identical link with fixed-fixed ends.

(c) If the slenderness ratio Sr = (Sr)D at the point of tangency, then the critical unit load does not depend on the yield strength of the column material.
Figure P11.41 Link AC supported by link BD.