Conductive 3D Printed PLA Composites: on the interplay of mechanical, electrical and thermal behaviours

I. Tirado-Garcia, D. Garcia-Gonzalez, S. Garzon-Hernandez, A. Rusinek, G. Robles, J.M. Martinez-Tarifa, A. Arias, Conductive 3D Printed PLA Composites: on the interplay of mechanical, electrical and thermal behaviours, Composite Structures, Volume 265, 2021, 113744, ISSN 0263-8223, https://doi.org/10.1016/j.compstruct.2021.113744.

Abstract – Additive manufacturing (AM) techniques represent a real challenge to manufacture novel composites with coupled multifunctional properties. This work focuses on the mechanical, electrical and thermal behaviours of 3D printed polymeric composites of polylactic acid (PLA) filled with carbon black (CB) conductive particles. The incorporation of conductive particles within the polymer matrix allows for programmable conduction paths via the printing process, whose electric properties are intimately coupled to thermo-mechanical processes. In this study, samples were prepared using a fused deposition modelling (FDM) printer, controlling the filament orientation to manufacture three different types: longitudinal (0°); transverse (90°); oblique (±45°) printing orientations. Different types of multifunctional characterisation have been made: (i) electro-thermal tests, evaluating the influence of electrical conductivity on the sample temperature due to Joule’s heating; (ii) thermo-electrical tests, analysing the influence of temperature on the DC resistance of the samples (iii) mechano-electrical tests, analysing the effect of mechanical deformation on the specimens’ electric resistance. The results show a strong dependence of printing direction on the material properties of 3D printed conductive-PLA and identify strong thermo-electro-mechanical interplays. The results of this work will contribute to the AM progress in functional electro-mechanical components with potential applications in biosensing devices, composite sensors, 3D electrodes and soft robotic industry.

Keywords – Additive manufacturing (AM); Conductive Polymer Composites (CPC’s); Fused deposition modelling (FDM); carbon black (CB); polylactic acid (PLA); Multifunctional materials

Towards Series Arc Fault Detection in More Electrical Aircrafts

M. G. d. l. Calle, G. B. d. María, D. Izquierdo, R. Martín, J. M. Martínez-Tarifa and G. Robles, “Towards Series Arc Fault Detection in More Electrical Aircrafts,” 2020 IEEE 3rd International Conference on Dielectrics (ICD), Valencia, Spain, 2020, pp. 866-869, doi: 10.1109/ICD46958.2020.9342025.

Abstract – The trigger of an electric arc represents an unacceptable risk to the safety of the aircraft and a blocking point to certify the new high-voltage architectures. These high-voltage networks are required to cover the growing electric energy demand for new developments. Thus, the study of the electric arc phenomenon, its detection and the parameters affecting its behavior is needed to progress along the path to the all-electric aircraft.

Partial discharges measurement during under-damped steep-fronted overvoltages

J. M. Martínez-Tarifa and G. Robles, “Partial discharges measurement during under-damped steep-fronted overvoltages,” 2020 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), Dubrovnik, Croatia, 2020, pp. 1-5, doi: 10.1109/I2MTC43012.2020.9129294.

Abstract – Inverter-fed drives have become essential in most industrial processes nowadays to control the speed of rotation of electric motors. Unfortunately, the insulation of these electric motors show unexpected failures due to the appearance of partial discharges (PD). These type of discharges undermine the insulation along time creating weak spots than can cause total breakdowns. Thus, the detection of partial discharges is a challenge that must be faced by electric motor manufacturers and users. The problem of detection is intensified because the voltage supplied to the motors is based on steep-fronted pulses and PD are also very narrow pulses so it is quite complex to separate them from the electrical interferences created by the train of square pulses. In this paper, two different radio- frequency (RF) sensors will be used to detect PD in an insulation system subjected to square voltages with low rise-times. The response will be analyzed in the UHF range to select the best option for the detection of those hazardous under-damped pulses.