Sensitivity law and probabilistic variation of elasto-plastic ultimate strength of imperfect plates

The mechanism of imperfection sensitivity of elastic-plastic plates under compression is complex as they undergo elastic and/or plastic buckling, dependent on their width-thickness ratio. The Koiter power law is extended by implementing the quadratic law so as to describe the elastic and plastic buckling of the plates with probabilistically varying initial deflection and yield stress. The finite-displacement, elastic-plastic analysis was conducted on simply-supported square plates under compression by varying the plate thickness, yield stress, and the initial deflection of a sinusoidal form. In accordance with the change of the mechanism of buckling, the power law is changed pertinently to describe the complex imperfection sensitivity of the compression plates in a synthetic manner. A theoretical framework to describe the probabilistic variation of the ultimate strength of the plates has been proposed, and has been put to use in the evaluation of the influence of width-thickness ratio.