Eight-plastic-hinge deformation behavior of multi-row cylindrical shells subjected to radial pressure

Study on the radial dynamic deformation behavior of cylindrical shell is helpful to constitute an anti-explosion structure.Due to the existence of two adjoining cylindrical shells,the deformation mode of multi-row cylindrical shells subjected to radial pressure was not the four-plastic-hinge framework.Based on mechanics analysis,quasi-static experiment,small explosion experiment and numerical simulation,the authors establish that the plastic deformation behaviors of multi-row cylindrical shells under radial pressure and the number of plastic hinges is eight.This eight-plastic-hinge framework consists of four moving hinges that the edges of plastic zone move ceaselessly outward and four fixed hinges that the comparative size of plastic zone is invariable.Furthermore,the size of rotational part and the place of plastic hinges are calculated.In view of the dynamic strain rate and strain hardening of material,the expressions of the plastic bending moments near the plastic hinges are presented.These results give us a theoretical foundation to use modal method to solve the large deformation problem of multi-row cylindrical shells.