Proof of elastic stability of crane elements was also made with use of FEM in case as buckling of plate fields subjected to compressive and shear stresses.
Factor [lambda] shows de facto "reserve" of elastic stability of load-carrying crane structure, in relation to the required value, coming out of position and loads value.
The proof of elastic stability is made to prove that ideally straight structural members or components will not lose their stability due to lateral deformations caused solely by compressive forces or compressive stresses.
In comparison to proof of static strength degree (factor W), the values of factor [lambda] becomes much higher, It shows that elastic stability reserve of load-carrying cranes structures is big.
The crack suddenly appears in this locality, as a result of the loss of the local elastic stability inside the system, leading finally to macroscopic fracture.
Then it becomes plausible, after a time, that the system will lose its macroscopic longitudinal elastic stability, and rupture instantaneously in the most compliant cross section.
The moment of failure is regarded as the loss of macroscopic elastic stability, the system having been prepared for this event by its entire history.
The failure of such a hoop element comes after the loss elastic stability and results in the fracture of the tube as a whole.
In some cases, during extension, the specimen can retain its continuity (rather outward appearance of the continuity) even after the loss of elastic stability.