Additive Manufacturability and Parametric Studies on an Extended Three-Dimensional Re-Entrant Auxetic Structure with...

Area of Science:

• Materials Science
• Mechanical Engineering
• Additive Manufacturing

Background:

• Auxetic honeycomb structures exhibit unique deformation, making them suitable for lightweight sandwich structures and impact energy absorption.
• Traditional 2D reentrant honeycombs inspire the development of modified 3D reentrant lattice structures.

Purpose of the Study:

• To propose and investigate a modified 3D reentrant lattice structure with a negative Poisson's ratio (NPR).
• To understand the influence of fabrication and design parameters on the printing quality and mechanical properties of these 3D structures.

Main Methods:

• Additive manufacturing (AM), specifically laser powder bed fusion (LPBF), was employed to fabricate 18Ni350 Maraging Steel samples.
• Compression tests were performed to evaluate the quasi-static stress-strain behavior.
• A tuned finite element model (FEM) was utilized for parametric analysis of design parameters.

Main Results:

• Reduced hatch distance and scan speed in AM led to decreased porosity and improved printing quality.
• Enhanced structural stiffness and yield strength were observed with optimized AM parameters for thin angled struts (diameter ≤0.5 mm).
• Parametric analysis confirmed the significant impact of reentrant angle, strut cross-section shape, and size on compressive properties.

Conclusions:

• The study presents preferred AM process variables for fabricating high-quality 3D reentrant lattice structures.
• Design parameters critically influence the mechanical performance, offering avenues for tailored material design.
• The developed 3D reentrant lattice structures show promise for advanced applications requiring specific mechanical responses.