A piece of material in compression is called a strut. If it is short and stubby it will fail by compressive stress, but if it is slender the failure mode is that of buckling. The load at which the strut buckles depends on the way in which the ends are restrained. Built-in ends resist buckling more than ends which are free to move. The apparatus shows how the buckling mechanism occurs, and the influence of the end restraint.
The apparatus comprises a sheet metal frame which supports four slender spring steel struts having loading platforms at their top ends.
Each strut has a different end constraint so that comparisons can be instantly made in a highly visible way.
a) Both ends pinned
b) One end pinned, the other end fixed
c) Both ends fixed
d) Base fixed, top free
For the first three, the ends move inwards as the strut buckles. The loading platforms act through relatively friction free guide bushes.
This equipment is part of a range designed to both demonstrate and experimentally confirm basic engineering principles. Great care has been given to each item so as to provide wide experimental scope without unduly complicating or compromising the design. Each piece of apparatus is self-contained and compact. Setting up time is minimal, and all measurements are made with the simplest possible instrumentation, so that the student involvement is purely with the engineering principles being taught. A complete instruction manual is provided describing the apparatus, its application, experimental procedure and typical test results.