Chapter 3, Problem 46E

Three pinned-end columns of the same material have the same length and the same cross-sectional area (see figure). The columns are free to buckle in any direction. The columns have cross sections as: (a) a circle, (b) a square, and (e) an equilateral triangle. Determine the ratios Pa: Pb: Pcof the critical loads for these columns.

The plane truss shown in the figure supports vertical loads F at joint D, 2F at joint C, and 3F at joint B. Each member is a slender circular pipe (E = 70 GPa) with an outside diameter of 60 mm and wall thickness of 5 mm. Joint B is restrained against displacement perpendicular to the plane of the truss. Determine the critical value of load variable F(kN) at which member BF fails by Eu1er buckling.

A column, pinned at top and bottom, is made up of two C 6 x 13 steel shapes (see figure) that act together. Find the buckling load (kips) if the gap is zero. Find required separation distance d(inches) so that the buckling load is the same in y and z directions. Assume that E = 30,000 ksi and L = 18 ft. Note that distance d is measured between the centroids of the two C shapes.

A vertical post AB is embedded in a concrete foundation and held at the top by two cables (see figure). The post is a hollow steel tube with modulus of elasticity 200 GPa, outer diameter of 40 mm, and thickness of 5 mm. The cables are tightened equally by turnbuckles. If a factor of safety of 3,0 against Euler buckling in the plane of the figure is desired, what is the maximum allowable tensile force Tallowin the cables?

An aluminum tube AB with a circular cross section has a sliding support at the base and is pinned at the top to a horizontal beam supporting a load Q = 200 kN (sec figure). Determine the required thickness t of the tube if its outside diameter d is 200 mm and the desired factor of safety with respect to Eu 1er buckling is n = 3.0. (Assume E = 72 GPa.)

An idealized column is composed of rigid bars ABC and CD joined by an elastic connection with rotational stiffness ßRIat C. There is a roller support at B and an elastic support at D with translationa1 spring stiffness ß and rotational stiffness ßR2. Find the critical buckling loads for each of the two buckling modes of the column. Assume that L = 3 m, ß = 9 kN/m, and ßR]= ßR1= ßL2. Sketch the buckled mode shapes.

The upper end of a WE × 21 wide-flange steel column (E = 30 × 103ksi) is supported laterally between two pipes (see figure). The pipes arc not attached to the column, and friction between the pipes and the column is unreliable. The base of the column provides a fixed support, and the column is 13 ft long. Determine the critical load for the column, considering Euler buckling in the plane of the web and also perpendicular to the plane of the web.

The figure shows an idealized structure consisting of rigid bars ABC And DEF joined by a linearly elastic spring ß between C and D. The structure is also supported by translational elastic support ß at B and rotational elastic support ßRat E. Determine the critical load Pcrfor the structure.

A fixed-end column with circular cross section is acted on by compressive axial load P. The IS-ft-long-column has an outer diameter of 5 in., a thickness of 0.5 in., and is made of aluminum with a modulus of elasticity of 10,000 ksi. Find the buckling load of the column.