Exploring the design space for nonlinear buckling of composite thin-walled lenticular tubes under pure bending

This paper presents an automatic finite element simulation scheme accounting for high geometric nonlinearity and the difference between linear and nonlinear buckling of composite thin-walled lenticular tubes (CTLTs). Parameterizing of cross-section shapes and generation of design space for CTLTs with both circular and parabolic arcs were accomplished, and several key factors were identified, in particular the contrary effect of lumbus length and parabolic coefficient on the bending stiffness anisotropy. The first quantitative comparison of triangular rollable and collapsible (TRAC) booms and CTLTs is given in terms of bending performance in two directions, showing that the optimal CTLT carefully selected from the design space demonstrates a comparable or even better performance than the TRAC boom. This is of great importance from both academic and engineering perspectives. Our efforts enhance the understanding of nonlinear buckling and post-buckling behavior of CTLTs, and provide guidelines for future design of CTLTs with desirable performance.