<p>Soft
actuators and sensors are currently used in many industrial applications due to
their capability to produce an accurate response. Researchers have studied
dielectric electroactive polymers (DEAPs) because these types of structures can
be utilized as actuators and as sensors being able to convert electrical energy
into mechanical and vice versa. However, production of this kind of structures
is complex and in general involve several steps that are time consuming.
Customization of these types of structures will be ideal to enhance the
performance of the devices based on the specific application. 3D printing
technologies have emerged as innovative manufacturing processes that could
improve fabrication speed, accuracy, and consistency with low cost. This
additive manufacturing technique allows for the possibility of increased device
complexity with high versatility. </p>
<p>This
research studied the potential of 3D printing technologies to produce DEAPs,
soft actuators, and flexible sensors. The study presents novel designs of these
composite flexible structures, utilizing the most flexible conductive and
nonconductive materials available for fused deposition modeling, achieving versatility
and high performance in the produced devices. <a>Produced
DEAP actuators showed an actuation and electric resistivity higher than other
electroactive structures like shape memory alloys and ferroelectric polymers.</a> In addition, this research describes the
electromechanical characterization of a flexible thermoplastic polyurethane,
(TPU), produced by additive manufacturing, including measurement of the
dielectric constant, percentage radial elongation, tensile proprieties,
pre-strain effects on actuation, surface topography, and measured actuation
under high voltage. DEAP actuators were produced with two different printing
paths, concentric circles and lines, showed an area expansion of 4.73% and
5.71% respectively. These structures showed high resistance to electric fields
having a voltage breakdown of 4.67 kV and 5.73 kV respectively. <a>Those results are similar to the resistant of the most used
dielectric material “VHB 4910”. </a></p>
<p>The
produced soft pneumatic actuators were successfully 3D printed in one continuous
process without support material. The structures were totally sealed without
the use of any sealing material or post process. Computational simulations were
made to predict the response of the designed structures under different
conditions. These results were compared with experimental results finding that
the theoretical model is able to predict the response of the printed actuators
with an error of less than 7%. This error is satisfactorily small for modeling
3D printed structures and can be further minimized by characterization of the
elastomeric material. Besides that, two different grippers were designed based
on the opening and closing movements of single bellows actuators. The
functionality of both designs was simulated and tested, finding that both
designs are capable lifting a heavier rigid structure. </p>
<p>Finally,
this study presents a computational simulation of a 3D printed flexible sensor,
capable of producing an output signal based on the deformation caused by
external forces. Two different sensors were designed and tested, working based
on a capacitance and resistance change produced by structural deformation. Computational
analysis indicate the capacitance sensor should undergo change of capacitance from
3 to 8.5 pF when is exposed to 30 kPa; and the resistance sensor should
experience an increase from 101.8 to 103 kΩ when is exposed to 30 kPa. </p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/12747026 |
| Date | 31 July 2020 |
| Creators | David F Gonzalez Rodrigez (9192755) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/3D_PRINTED_FLEXIBLE_MATERIALS_FOR_ELECTROACTIVE_POLYMER_STRUCTURES_SOFT_ACTUATORS_AND_FLEXIBLE_SENSORS/12747026 |
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