Lateral deformation behavior of internally fin-stiffened tubes

Thin-walled tubular structures are frequently used in energy absorption applications; however, the performance of increasing their lateral compression remains a significant challenge. This study addresses the necessity to enhance the tubular structures' lateral energy absorption capacity. To this end, the study proposes an integration of an internal stiffener with simple geometry, allowing for the deformation to be controlled parametrically. Using carbon fiber reinforced nylon (CFRN) tubes manufactured via 3D printing, the influence of internal fins with varying angles and positions on mechanical behavior under quasi-static lateral loading is systematically investigated. Experimental results demonstrate that the optimal stiffened configuration achieves up to 3.2 times higher absorbed energy and 2.5 times greater specific energy absorption (SEA) compared to baseline hollow tubes. Finite element simulations validated the experimental observations and provided insights into deformation mechanisms. The proposed design offers a versatile and scalable solution by providing tunable performance through geometric changes such as fin orientation, position, and wall thickness. This design is regarded as a source of inspiration for subsequent studies. Given that the structure's suitability for the extrusion technique allows the use of metal materials, it is expected to create potential for various and demanding applications in the aerospace, automotive, and defense industries.