Abstract: Dynamic buckling and plastic collapsing of rectangular plates under solid-fluid in-plane impact are in vestigated experimentally. The plates exhibit three different critical conditions: bucklin'g, plastic incipience and plastic collapsing. The conditions are defined by three kinds of critical equivalent membrane strains. Based on the definitions, the critical values of each plate are determined. The modes of flexural motion and plastic collapsing of the plates are observed in the experiment. Moreover, the e...