In-Plane Compressive Responses of Non-Homogenous Re-Entrant Honeycombs Fabricated by Fused Deposition Modelling.

Area of Science:

• Materials Science
• Mechanical Engineering
• Additive Manufacturing

Background:

• Auxetic structures exhibit a negative Poisson's ratio, leading to enhanced mechanical properties.
• Re-entrant honeycombs are a key class of auxetic structures with potential applications.

Purpose of the Study:

• To propose a simple method for creating non-homogeneous re-entrant honeycombs.
• To investigate the influence of chevron crosslink geometry on mechanical behavior.
• To explore the auxetic performance of additively manufactured structures.

Main Methods:

• Fabrication of re-entrant honeycombs using Fused Deposition Modelling (FDM) with polylactic acid (PLA).
• Experimental investigation through in-plane quasi-static compression tests.
• Numerical analysis using a validated Finite Element (FE) model (LS-DYNA R11.0).

Main Results:

• Mechanical properties (elastic, plastic, densification) were extracted from compression tests.
• FE model provided insights into deformation behavior and auxetic performance.
• Design parameters of chevron crosslinks (length and thickness) were found to be crucial.

Conclusions:

• The mechanical performance of re-entrant honeycombs is tunable by controlling chevron crosslink geometry.
• Additive manufacturing offers a viable route for fabricating these tailored auxetic structures.
• This study demonstrates a practical approach to optimize auxetic material design.