Dynamic buckling and post-buckling of imperfect columns under fluid-solid interaction

Dynamic buckling and post-buckling properties of simply supported imperfect columns under axial fluid-solid interaction are experimentally and numeric ally investigated in this study. By observing the elastic-plastic responses of imperfect columns, three critical criteria are defined for the columns with prescribed imperfection, namely, the dynamic buckling criterion, the d ynamic yielding criterion and the plastic collapse criterion. The relevant critical impulses are determined for each column. The dynamic buckling and collapse mechanism, and the effects of dynamic load duration and initial im perfection of column on the elastic-plastic dynamic buckling and post-buckl ing properties are examined. The results indicate that, for columns with sm all imperfection, dynamic buckling will occur with the increase of the flui d-solid impulse. For columns with large imperfection, however, their failur e is dominated by the flexural responses. The dynamic buckling and post-buc kling characteristics of columns under fluid-solid interaction are also com pared and discussed with respect to those of columns under solid-solid impa cts. It is found that they are different from those of columns subjected to either impulsive impact or impact owing to suddenly applied load. (C) 2001 Elsevier Science Ltd. All rights reserved.