Shape Memory Polymer Composite Actuator: Modeling Approach for Preliminary Design and Validation

Abstract

The work at hand focuses on the modeling, prototyping, and experimental functionality test of a smart actuator based on shape memory polymer technology. Particular attention is paid to the specific modeling approach, here conceived as an effective predictive scheme, quick and, at the same time, able to face those nonlinearity aspects, strictly related to the large displacements shape memory polymers usually undergo. Shape memory polymer composites (SMPCs) may play a critical role for many applications, ranging from self-repairing systems to deployable structures (e.g., solar sails, antennas) and functional subcomponents (e.g., pliers, transporters of small objects). For all these applications, it is very important to have an effective tool that may drive the designers during the preliminary definition of the main parameters of the actuation system. For the present work, a SMPC plate sample has been conceived and realized in view of aerospace applications. An external fibre optic sensor has been then fixed with special adhesive. The temperatures needed for the activation of the Shape Memory Polymer (SMP) and strain storing have been provided by a thermo-gun and complete load–unload cycles, including strain storing, have been performed. Experimental displacements and strains have been used to validate a dedicated predictive theoretical approach, suited for laminates integrated with SMP layers.

Adaptive structures for noise and vibration guidance, monitoring, and control

“…The optimal working of this system depends on specific parameters as: the most convenient excitation frequency, characterized by the highest ratio of delamination stress over required power [13]; the logic to coordinate multiple transducers to maximize their local action to adequately protect zones far from the source or scarcely receptive being too close to constraints or stiffening. The laboratory is investigating in particular this second topic, that is to say, the coordination of more excitation channels, phasing the signals to achieve advantageous constructive interference [14]. The just mentioned multichannel logic is investigated onto a slat representative specimen and a trade-off between the Lamb wave excitation and the optimal phasing of the transducer is under construction.…”

“…As well as for SMOS, also GAINS focuses on icephobic coatings, the electrothermal resistances and ultrasound waves. STAD, in particular, is working on an IPS based on multichannel excitation [14]. The activity of STAD within the Project is summarized in the scheme of Figure 13.…”

Distributed sensing based real‐time process monitoring of shape memory polymer components

“…20,22 Moreover, surface-mounted fiber Bragg grating (FBG) sensors have the ability to measure temperature and strain variations for a short distance (approximately 1 cm) on an SMPC. 23,24 Thus far only a few prototype SMPC applications have been monitored during their shape memory process at the actual operational environment. [25][26][27] The performance evaluation and process monitoring techniques currently used for large SMPC components are given in Table 1.…”

“…Thermal imaging cameras and thermocouples have been used to investigate the heat distribution inside SMPCs during the shape memory process 20,22 . Moreover, surface‐mounted fiber Bragg grating (FBG) sensors have the ability to measure temperature and strain variations for a short distance (approximately 1 cm) on an SMPC 23,24 . Thus far only a few prototype SMPC applications have been monitored during their shape memory process at the actual operational environment 25–27 .…”

A Focus on Soft Actuation

“…The research published in this Special Issue spans from theoretical [2][3][4][5][6][7] and applied [2,3,5,7-9] methods for actuator design to actuation materials [7] and showcasing of actuation systems [2,3,5,[7][8][9]. For research contributions in the field, the main measure of success would be the new theoretical and practical knowledge allowing overcoming the challenges towards creation of robust, reliable soft actuation.…”