Effect of the Strut Thickness on the Mechanical Properties, Deformation, and Failure Mechanisms of Vascular Bundle–Inspired Structures

ABSTRACT In this work, the influence of strut thickness on the deformation and failure mechanisms of new vascular bundle–inspired structures, which exhibit comparable or better mechanical properties than honeycomb and star‐shaped lattices, is presented. The novelty of the work lies on the design of the structure; this is a new structure, and its behavior has not been reported elsewhere. Structures consisting of 0.2, 0.5, 1.0‐, and 1.15‐mm strut thicknesses were designed, modeled, fabricated, and tested. A finite element model of a quasi‐static compression test is developed in ANSYS Explicit Dynamics to evaluate the deformation and failure mechanisms of the various structures. It is demonstrated that 0.2‐ and 0.5‐mm structures exhibit stretch‐dominated stress–strain behavior, whereas 1.0‐ and 1.15‐mm structures show bend‐dominated stress–strain characteristics. As the strut thickness increases, there is an increase in peak stresses (with reported peak stresses of 1.3, 1.4, 5, and 5.1 MPa for 0.2, 0.5, 1.0, and 1.15 mm, respectively) and energy absorption (reported values of 33.84, 31.48, 159.28, and 179.07 J for thicknesses of 0.2, 0.5, 1.0, and 1.15 mm, respectively) characteristics. Poisson's ratio values of the samples ranged between 0.6 and 1.2. Additionally, the deformation mechanisms transform from perpendicular collapse of the structure to 45° bending (shearing) of the structure from low to higher strut thickness. As the strut thickness increases, the failure mechanisms transform from ductile fracture to near‐brittle failure of the structures. The findings in this paper provide key insights into the design and fabrication of next‐generation vascular bundle–inspired multifunctional materials for lightweight structural applications. As a contribution, the energy absorption and peak stress values for the vascular bundle structures presented in this paper are comparable to published data on similar PLA lattice structures.