Design, Fabrication, and Mechanical Analysis of Auxetic Cementitious Tubular Composites: An Experimental and Numerical Study

Abstract

Auxetic cementitious composites exhibit enhanced mechanical performance such as high energy dissipation capacity and crack resistance. Such characteristics position them as promising materials for advanced construction applications. This study investigates the design, fabrication, and mechanical performance of novel auxetic cementitious tubular composites under quasi-static compressive loading. Auxetic cementitious tubular composites (ACTCs) were fabricated by casting glass fiber-reinforced mortar into a 3D-printed auxetic tubular mold. A combination of experimental and numerical methods was employed, including uniaxial compression tests, digital image correlation (DIC), and finite element modeling (FEM). This study further conducted a parametric analysis to examine the effects of geometric parameters, including wall thickness, porosity, and height, as well as varying loading conditions, on the failure mechanisms, stress-strain behavior, Poisson's ratio, and energy absorption characteristics of ACTCs. Experimental and numerical results confirmed the auxetic behavior of ACTCs under compressive loading. The stress-strain response exhibited distinct phases, including elastic deformation, peak stress, and post-peak softening. Failure mechanisms were primarily governed by plastic strain concentration, crack propagation, and densification. Cracks initially formed at the minor axis ends of elliptic perforations and propagated with increasing strain. FEM simulations accurately captured deformation behaviors and mechanical responses, aligning closely with experimental findings, while DIC analysis validated strain localization patterns. Parametric analysis results indicated that increased wall thickness enhanced peak stress and energy absorption, while porosity adjustments influenced both load-bearing capacity and auxeticity. The developed ACTC presents a novel design approach, proving its feasibility and exhibiting substantial potential for engineering applications.