Title:
Improving the Confinement of Concrete Structural Members with Steel Auxetic Truss Lattice Reinforcement
Author(s):
Vitalis
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
11/3/2024
Abstract:
When auxetics are embedded in an interpenetrating phase composite (IPC) matrix to fabricate auxetically reinforced composite materials, the same mechanism that provides beneficial mechanical properties to a bare truss lattice can be harnessed to increase the confinement pressure acting upon the composite matrix. The development of mismatch strains between the matrix and the truss lattice phase, under sufficient elastic contrast of the two constituents, allows additional confinement pressure buildup, adding to the passive confinement pressures generated by the expansion of the effectively confined matrix core. Furthermore, the presence of auxetic truss lattices inside a composite matrix increases the hydrostatic compression of the matrix while also suppressing crack openings, assuming the two phases are adequately bonded. Thus, the peak stress and ductility of an IPC can be tailored and remarkably enhanced compared to unconfined or traditionally confined specimens. In this work, we study the influence of using auxetic reinforcement for confining structural members through experimental prototyping, analytical and computational means. Specifically, two re-entrant families of structures with varying geometrical features and relative densities of ?*=5%, are studied in IPCs. Explorative parametric computations are utilized combined with a Voigt model to determine promising candidate architectures based on the percentage increase of the confinement pressure they provide in a wide range of transverse moduli. The laser powder bed fusion method is utilized, along with a precipitation hardening 15-5 stainless steel pre-alloyed powder to manufacture truss lattice specimens. Truss lattice-reinforced structural member prototypes are manufactured and employed for studying the behavior of auxetic IPCs in cubes, columns, and beams. A cementitious mortar mix design is specifically designed to cast the composite matrix. Comparisons between unconfined specimens, conventionally reinforced.