Magnet-polymer composite transducers
Nguyen, Quang Vinh
Date of Issue2011
School of Materials Science and Engineering
Current actuation technologies do not provide a satisfactory solution to the requirement of having a muscle like motion, such motion will be very useful in robotics, MEMS and biomedical applications, etc. Hence a magnetically actuated material was studied as an “artificial muscle”. The material is a composite of a soft polymer with magnetic material as the filler (Magpol). Magpol composites are a new class of bio-inspired smart soft transducers for morphing, damping, and artificial muscle applications. Magpol exhibits large changes in shape and physical properties in response to an external magnetic field. This shape changing behavior of Magpol in an external magnetic field was studied and actuation performance investigated. The large change in electrical resistivity driven by the shape change was also examined for sensing applications. This versatile combination of actuation and sensing behavior results in attractive transducers. Various actuation modes, including contraction, elongation and deflection were studied. These actuation modes can be combined to produce complex motions. A novel coiling mode was observed. Simply by changing boundary conditions, Magpol can exhibit a change in actuation mode from axial contraction to a novel coiling mechanism. The magnetic buckling which results in coiling was studied by computer simulation and analytical modeling. The analytically predicted magnetic fields for buckling agreed well with experimental values. The relationship between strain and magnetic field suggested that post buckling behavior is a stable symmetric bifurcation, which is useful for continuous actuation.