Buckling
From DT Online
Description
A Structural Member in Compression (i.e. a Strut) is more likely to buckle first when subjected to pressure  assuming the Strut is made of a sensible material and not something so brittle it is likely to explode under pressure(!)
See  'The New Science of Strong Materials: Or Why You Don't Fall Through the Floor' by J.E.Gordon
Features and Applications
The point at which a strut might buckle can be assessed using a simplified form of Euler's Buckling Equation as follows:
Where:
 Pcrit = the Critical Force at which the strut will start to buckle.
 E = the Young's Modulus of the material (obtainable from tables or by experiment).
 Capital I = the Moment of Inertia about the Neutral Axis (for a rectangular beam this is its breadth times the depth cubed divided by 12).
 L = the length of the Strut (this is taken as the total length if the strut is assumed to be pinjointed at each end but would vary with other fixing methods  see Euler's Buckling Equation)

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