Structure Response Of Multi-row Cylindrical Shells Under Explosion And Shock

The study on the structure response of the multi-row cylindrical shells exposed to explosion and shock aims to describe systematically and exactly the deformation of multi-row cylindrical shells and determines the response of an energy-absorbing structure made of multi-row steel pipes to explosion shock, and to what degree the explosion shock is weakened. It is helpful to the reliable design of the modem military protective works and the solution to important problems of works, which usually involves large deformation, non-linearity, instantaneous loading, coupling (interconnection) and complicated constraints.The paper deals chiefly with the axial and radical action of loads on cylindrical shells. Through theoretical analysis and experiments, the theoretical system for the deformation of a single shell and multi-row shells with load is exerted on is set up.With the sum-up of the previous study of a single shell, the discussion on the axial load is focused on the research of the deformation and energy-absorbing mechanism of a single shell and multi-row shells by adopting the quasi-static experiments and the experiment in which 10-kg-hammer drops 10 meters. The research shows that the axial compression cylindrical shells behaves obviously the same in both the quasi-static and hammer-dropping experiments, and that with the rise of loading speed, the strain-rate effect and the material hardening become more obvious. The research also indicates that with the increased ratio of shell's diameter to the shell wall thickness, the number of the buckling edges of an axially-shocked shell tends to increase and with the appearance of transition zones. The new phenomenon of transition zones is explained from the angle of energy and the criterion of the number of folding edges is established. Combined with the concept of nominal average collapse load, the calculation method for dynamic average collapse load is set up with strain-rate intensifying effect involved.In the discussion on the radical action of load, quasi-static experiment, experiments with 10-kilo hammer dropping 5 and 10 meters and the 45-gram and 7-kilogram TNT explosion experiments are adopted to explore, from different angles, the deformation of a single shell and multi-row shells and determine the formation and development laws of plastic hinges. The deformation modal and mechanism mode of multi-row cylindrical shells under explosion and shock are established. Modal method is used for theoretical analysis to set up a theoretical structure response system of the multi-row shells. Experiments show that the multi-row shells acted on by radical load yield to take a quadrilateral and form quadrilateral buckling.