DISCRETE FIELD STABILITY ANALYSIS OF PLANAR TRUSSES

The techniques of discrete field mechanics are used to perform an elastic stability analysis of planar X-braced columns. Closed-form analytical formulas are derived that are independent of the number of joints in the system; thus, the solution of large, simultaneous equations is avoided. The explicit formula derived is used to develop a series of curves showing the critical buckling load for various planar, X-braced, truss configurations and geometries. A comparison of critical buckling loads for the X-braced truss indicates that the modified Euler critical load may very up to 85% from the loads obtained by the discrete field analysis method. The study also shows that as the number of panels increases from four to 32, the buckling-load ratios also increase. The X-braced truss depth has a direct relationship to the shearing force, which in turn will affect the buckling load of the truss system. Variations in chord member areas create variations in buckling-load ratios. The effects on the buckling ratios of the last two factors tend to diminish as the number of panels increases.