Fiber reinforced composite manufacturing for passive actuators

The aim of this work is to design, characterize, and manufacture a new class of passive actuators that are composed of natural chitosan biopolymers and 3D printed carbon fiber composites (CFRP). These actuators leverage variation in the physical properties of chitosan films with respect to their water content to produce programmable deformation. To control the actuator and its performance, various fundamental physicochemical material characterizations such as microstructural, thermal, hygroscopic swelling for chitosan films, and mechanical analyses were conducted for both materials to validate their properties for the intended application. The morphological behavior confirmed that there was good miscibility with no phase separation in chitosan film, and 3D printed CFRP possesses consistent accuracy irrespective of its minor defects. The swelling ratio of chitosan films was determined as a means of measuring the tunable hygroscopic expansion. According to thermal and mechanical analysis, both polymers possess strength and stiffness desirable for actuator design. Initial built prototypes of small-scale actuators were tested to guide the manner in which the passive actuation behavior could be directed for functional transformations. The results were integrated into CAD software to simulate a large-scale prototype that was subsequently fabricated. The experimental and simulated motions of the large-scale actuator were compared, and the overall performance was discussed with respect to structural integrity and response time.