Buckling is a stability problem which occurs in practice when slim components are subjected to compressive loading. Following a "disturbance" to its equilibrium, such as caused by compressive loading, a stable system returns to equilibrium when the loading is removed. If the compressive load increases excessively, instability of the system results. The component buckles and fails. The critical compressive load at which the system becomes unstable is termed the buckling force. A simple model for representing stability problems is a two-part bar with an elastic joint which remains stable up to a certain load level. If the buckling force is exceeded, the bar suddenly buckles and so becomes unstable. SE 110.19 is used to investigate simple stability problems on a buckling bar under different conditions. The buckling bar is in two parts, with a central articulated joint. A compressive load is applied to the bar by a lever and weights. The infinitely variable loading is determined precisely with the aid of a scale on the load application lever. Experiments can depict a variety of conditions, such as an elastic joint or an elastic clamp fixing. Two tension springs serve as the elastic joint. For the elastic clamp fixing option, a steel leaf spring is mounted in the bottom joint. The variable length of the leaf spring means various degrees of clamping are possible. The two cases can be combined. Another experiment demonstrates the influence of additional shear forces. It involves applying a shear force to the joint in the buckling bar with a cable and a weight. In all experiments the buckling bar is placed under load until it reaches an unstable situation. The length of the lever arm at which the buckling bar buckles is read from the scale and the buckling force is then determined. The various elements of the experiment are clearly laid-out and housed securely in a storage system. The complete experimental set-up is arranged in the frame SE 112. The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments. |