Snowwhite2 paper: Monotonic and cyclic compressive performance of self-monitoring materials

Our exploration of scientific advancements made possible by the Sharebot Snowwhite2 SLS 3D printer takes us to a fascinating study: “Monotonic and cyclic compressive performance of self-monitoring MWCNT/PA12 cellular composites manufactured by selective laser sintering“. In this piece, we’ll break down the core problem this research aimed to solve and the key discoveries they made. For those who want to dive deeper, we’ll also provide the original abstract and all referenced sources.

Understanding the study and its main result

This study looked at the mechanical and electrical properties of special 3D-printed structures when squished. These structures were shaped like honeycombs and made using our Sharebot Snowwhite2 3D printer. They used two different materials: pure PA12 (a type of plastic) and a mix of PA12 with carbon nanotubes (MWCNTs).

Here’s what they found:

• Pure PA12 structures were stronger and could absorb more energy, especially the denser ones (30% and 40% solid material).
• The MWCNT/PA12 structures were not as strong or stiff as the pure PA12 ones, but they were very good at absorbing energy (up to 53% efficiency).
• Most interestingly, the MWCNT/PA12 structures could sense strain, meaning their electrical resistance changed when they were deformed. They were very good at this, acting like built-in sensors.
• When these MWCNT/PA12 structures were repeatedly squished, their electrical resistance significantly increased as they got damaged. This means they could potentially detect damage as it happens.

Main result

The main discovery is that 3D-printed honeycomb structures made from a blend of PA12 and carbon nanotubes (MWCNTs) can act as self-sensing materials. They are not only good at absorbing energy but also have the remarkable ability to detect strain and damage as it occurs. This opens up possibilities for creating smart, lightweight structures that can sense their own condition, which could be useful in many applications like aerospace or automotive industries for real-time monitoring.

Monotonic and cyclic compressive performance of self-monitoring MWCNT/PA12 cellular composites manufactured by selective laser sintering

Muhammad Umar Azam (a), S Kumar (b), Andreas Schiffer (a) (c)
a) Department of Mechanical and Nuclear Engineering, Khalifa University of Science and Technology, Abu Dhabi, 127788, United Arab Emirates
b) James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ, UK
c) Advanced Research and Innovation Center (ARIC), Khalifa University of Science and Technology, 127788, Abu Dhabi, United Arab Emirates

Ref.: https://www.sciencedirect.com/science/article/pii/S2666682025000106

Abstract

Herein, we experimentally investigate the mechanical and piezoresistive properties of selectively laser-sintered cellular composites under monotonic and cyclic compressive loading. Hexagonal honeycomb structures (HHSs) with relative densities of 20 %, 30 %, and 40 % were 3D printed from a ball-milled nanocomposite powder of multi-walled carbon nanotubes (MWCNTs) and polyamide 12 (PA12) with 0.3 wt.% MWCNTs. The pure PA12 HHSs exhibited lower porosity and superior mechanical properties, including collapse strength, elastic modulus and energy absorption, particularly at higher relative densities (30 % and 40 %). Notably, the specific energy absorption for the PA12 HHSs reached 24 J g⁻¹, under out-of-plane compression at 40 % relative density. Compared to neat PA12, the MWCNT/PA12 HHSs showed a reduction in strength and modulus but demonstrated excellent energy absorption efficiency of up to 53 %. Moreover, MWCNT/PA12 HHSs exhibited exceptional strain-sensing capabilities in the elastic region with gauge factors of up to 25. Cyclic tests showed that the zero-load resistance increased significantly as damage progressed during the collapse phase, highlighting their potential for application in smart, lightweight structures with integrated strain and damage-sensing functionalities.