Session: 03-13-01: Multifunctional Electronics and Energy Devices

Paper Number: 94945

94945 - Structure-Resistance Relationship of 3D Printed Electrically Conductive Woodpile-Structured Metamaterials 

The advent of Additive Manufacturing (AM) brought into existence a whole host of new possibilities, from 3D Printed large-scale constructions to 3D printed personalized wearable (bio)sensors. The flexibility in design and customization provided by AM technologies offers wide range of applications that would be beneficial in measuring acoustic, mechanically implied, and human-induced forces such as smart insoles and strain sensors. Fabrication of functional materials and devices with AM enables peculiar shapes with specific stress-strain vs. resistance characteristics as a result of tailored internal architecture.

The ability to engineer the material properties combined with precisely designed material arrangement can manifest into metamaterials that exhibit properties which are not observed naturally. The shape, geometry, size, orientation, and arrangement of surface structures on metamaterials are what gives them their unique properties. Extrusion-based AM approach with conductive feedstock material is employed here to fabricate this class of materials with altered geometric parameters.  

This work proposes a metamaterial with a woodpile arrangement constructed of its electrically conductive constituent material. The bending-dominated nature of woodpile structure has been observed to inhibit variability in resistance when measured under compression. The compressive behavior of bending-dominated structures consists of three regions: elastic region and flat plateau region, where strain increases with constant stress followed by densification and changes in surface area. Hence, variation in electrical resistance is expected as the structure is compressed with different magnitude of forces.

Tailored properties and material arrangement were achieved by programming the tool-path of 3D-Printer (Original Prusa i3 MK3S+) in all three directions with control over the geometric parameters (e.g., porosity, strut diameter). The information is then fed to the machine in the form of G-code instructions. Such precise control of porosity has opened exciting new opportunities in the field of elastic metamaterials.

During the fabrication of samples, the heat profile of the conductive feedstock material was kept in the temperature range (150-180 °C) as per material specifications. The material resistance is observed to be sensitive to fabrication parameters such as extrusion feed rate, build platform, and nozzle temperature. Therefore, all the parameters were set according to the recommendations of the manufacturer.

Furthermore, uniaxial compression using an INSTRON universal testing machine will be carried out by simultaneously measuring the change in the electrical characteristics. The resistance will be measured as a function of the strain with an ohmmeter connected to the specimen. The experiment will be repeated for samples with geometric alterations of the material’s structure. The metamaterial is expected to possess specific resistance and enable free-form fabrication of strain sensor devices with tailored electrical properties.

This ability to synthesize electrical properties of 3D Printed metamaterials can lead to exciting developments in customizable transducer designs that can be implemented in niche applications. Some forces that are subjected for measurement would not be achievable using commercially available sensors currently in the market and would require bespoke designs of sensors.

Presenting Author: Rahmat Agung Susantyoko Dubai Electricity & Water Authority (DEWA)

Presenting Author Biography: N/A

Authors:

Hayk Vasilyan Dubai Electricity & Water Authority (DEWA)
Oginne Lapuz Dubai Electricity & Water Authority (DEWA)
Rahmat Agung Susantyoko Dubai Electricity & Water Authority (DEWA)
Ahmad Almheiri Dubai Electricity & Water Authority (DEWA)
Mozah Alyammahi Dubai Electricity & Water Authority (DEWA)