*Additive manufacturing technologies and products have seen significant growth in the last decade but have the potential to see greater advancement with the addition of adjustable material properties in filaments vastly expanding the product range. Polylactic acid (PLA) is a common fused deposition modeling (FDM) material used for additive manufacturing. Currently, filament materials are limited in terms of electrical properties with the majority of filaments being dielectric. Imparting electrical properties via nanofiller modification of traditionally insulating PLA is an exciting direction for multi-functional additive manufacturing. The work presented in this manuscript endeavors to develop an understanding of the relationship between nanofiller-modified PLA and its piezoresistive strain sensing performance under different manufacturing conditions. Specifically, we vary the extrusion temperature and the number of re-extrusions of a nanofiller and pulverized PLA mixture in order to understand the effect of manufacturing parameters on the electrical properties of carbon nanofiber (CNF)-modified PLA. These experimental values are then used to calibrate a piezoresistivity model which is used to assess the performance of this material in a 3D-printed strain sensor. The results of this work enable a better understanding of how to create electrically adaptable FDM filament to meet specific electrical properties desired in a multi-functional additive manufacturing environment. These electrical properties are needed for the production of electroactive polymers (EAPs), piezoresistive sensors, and other electrically conductive components which have immense potential for on-demand and highly customizable structural health monitoring (SHM) sensors*.


A Computational Study of Strain Sensing via 3D Printed CNF-Modified PLA Strain Gauges

Division / Sponsors: 
Aerospace Division

Paper Proceedings: https://asmedigitalcollection.asme.org/SMASIS/SMASIS2020/volume/84027

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