In the case of a post-critical failure, a substantial change in the geometry of a structure occurs. After reaching the instability of the equilibrium, a stable, strong position is reached again. The post-critical analysis requires an experimental approach. It is necessary to manually load the structure in increments step by step.
This article shows the post-critical analysis. A structural component can be imagined as a flat roof subjected to compression from the outside. When slowly increasing the compression, it is visible that the load is absorbed by the compression stress and transferred to a support.
When a certain compressive load is reached, the structural system becomes unstable and the post-critical failure occurs.
When increasing the load again, it is primarily absorbed by tensile stress in the structural component.
Figure 04 - Post-Critical Analysis: Increasing Load
Generally, the second-order analysis cannot detect the post-critical failure due to the linearisation of the deformation geometry description.
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