TAILORING THE ELASTIC POSTBUCKLING RESPONSE OF THIN-WALLED CYLINDRICAL SHELLS FOR APPLICATIONS IN MECHANICAL DEVICES AND ADAPTIVE STRUCTURES

Postbuckling response, long considered mainly as a failure limit state is gaining increased interest for smart applications, such as energy harvesting, frequency tuning, sensing, actuation, etc. Cylindrical shells have received less attention as structural form to harness elastic instabilities due to their increased modeling complexity and high imperfection sensitivity. Yet, preliminary experimental and computational evidence indicates that the elastic postbuckling response of cylindrical shells can be controlled and potentially managed. Further, cylindrical shells offer desirable features for the design of mechanical devices and adaptive structures that other forms cannot attain without additional external constraints. This paper presents a study on tailoring the elastic postbuckling response of thin-walled cylindrical shells under compression by means of non-uniform wall stiffness distributions. The pattern of stiffness distribution was designed by discretizing the shell surface into cells and thickening selected cells with respect to a baseline uniform wall thickness. Diverse patterns were characterized in the way of how they affect the postbuckling response through numerical simulations using the finite element method. Results show that the elastic postbuckling response can be tailored into three response types: softening, sustaining, and stiffening; and that number, sequence/time and location/space of localized buckling events can be designed. This work provides new knowledge on the means to design the cylindrical shells with controlled elastic postbuckling behavior for applications in smart materials, mechanical devices, and adaptive structures.