Dynamic response, buckling and collapsing of elastic-plastic straight columns under axial solid-fluid slamming compression—I. Experiments

Abstract The dynamic behavior of straight elasto-plastic columns subjected to axial solid-fluid slamming compression is investigated experimentally in the present study. Two classes of columns are tested: large slenderness columns with the static Euler strain e crE smaller than the yield strain e y and middle slenderness ones with the e crE close to the e y . Three critical conditions for each of the columns are observed from the experiments: plastic incipience, buckling, and plastic collapse. These conditions are defined by introducing three critical loading strains: plastic, buckling, and collapse axial loading strains. The three critical strain values for each tested column are reported in the paper. The results indicate that: (1) the plasticity in a column appears first at the center and the plastic region is always at the middle length; (2) according to the buckling definition, the type 1 columns buckle elastically while the type 2 buckle plastically: (3) the column's load-carrying capacity is insensitive to the elasto-plastic loading histories (sequences) which the structure experiences before the plastic collapse occurs and is essentially governed by the dynamic post-buckling elasto-plastic behavior in one slamming: and (4) at the critical buckling loading magnitudes the column's response becomes dominated by motion in the fundamental mode.