A global FE–local analytical approach to modelling failure in localised buckles caused by crash

Localised buckles can occur in crashes when compressive stresses are dominant. However, due to their local appearance, they might be overlooked by a finite element analysis, meaning that local failure due to buckling will not be predicted. This could, for example, be catastrophic in the case of the crushing of a fuel tank or the impact on a ship hull, which could then lead to unpredicted and dangerous leakage. Methods to analytically assess the onset of such buckles are readily available. However, an off-the-shelf solution to predict the behaviour of them after the initial onset is not on hand. Therefore, an analytical method is developed that can predict the behaviour of a buckle after its onset, even in complex multi-axial states of stress that may be expected in crash scenarios. The strain over the buckle is captured as well, meaning that material failure can be predicted using existing material failure models. Also, the analysis is valid up to moderately thick shells, as would be expected in maritime structures. The proposed analytical method shows good agreement with a highly detailed finite element (FE) model, which only considers a single localised buckle. The goal would be to use the proposed method in conjunction with large-scale FE models, where the length of a shell element is equal to several times the thickness.