Buckling

Mechanical structures can buckle under the influence of certain critical compressive forces acting on the longitudinal axis. "Kinking" is the technical term for a loss of stability that can be sudden or continuous.

For members or beams with a load-bearing function, buckling has a destructive effect if the unstable structure can no longer fulfill its original function in its new, curved equilibrium position. This applies to both engineered and organic rod forms such as bones as part of a skeleton or grasses and trunks.

In the course of buckling, structures undergo changes in shape that occur at different speeds. The extent of this depends on the type of load to which the bar is exposed, which is referred to as the buckling load (critical load F_k ). Whether a compressive force becomes a buckling load and jeopardizes the stability of a member depends on the following correlated factors:

• Bearing of the bar ends (Euler buckling cases) & buckling length
• Cross-sectional shape, moments of area A & I
• Material properties (if there is elasticity: level of modulus of elasticity and yield point)
• Type of stress (compressive force progression and/or bending moment along the bar length)