3D printing technology of stimuli-responsive materials, also known as 4D printing, has recently emerged as an innovative method for designing and manufacturing functional objects, devices, and actuators with complex architectures, and time-changing shape and properties. 4D printing is particularly interesting for the manufacturing of soft actuators with complex design, suitable for remotely-controlled manipulators, soft robotics, and reconfigurable optical systems. Despite such enormous opportunities, current additive manufacturing technologies are still far from being a robust fabrication platform for systems with embedded optical functionalities. This is especially relevant for fabricating 4D optical components and devices, which might enable a novel class of devices, that are recongurable and programmable by external optical signals. To this aim, an engineering of the 3D printing technologies for active and photoresponsive materials is needed, allowing for going beyond the consolidated current printing methods, developed mainly for passive optical materials. The present thesis aims to design photoresponsive actuators through the combination of 4D printing, experimental activity, and numerical simulations. The devices consist of polymer cantilevers printed by fused deposition modelling (FDM) and functionalized by photochromic molecules. The approach here developed allows printing mm-scaled levers that can be controlled by utilizing external ultraviolet and visible laser beams, with characteristic actuation times of the order of a few seconds. The cantilever deflection upon external light control is characterized, evidencing fine control of the polymer beam positioning by varying the intensity of the control light beam. Finite elements simulations of the actuation process were carried out, and the results were compared with the experimental ones. The results of this study pave the way for a novel class of actuators, which are addressable precisely and remotely by light beams, thus advantageous in autonomous microsystems when an electrical energy source is not feasible.
Attuatori foto-responsivi realizzati tramite stampa 4D: test sperimentali e simulazioni agli elementi finiti.
4D printed photo-responsive actuators: experimental tests and finite element simulations.
DE DONNO, CHIARA
2018/2019
Abstract
3D printing technology of stimuli-responsive materials, also known as 4D printing, has recently emerged as an innovative method for designing and manufacturing functional objects, devices, and actuators with complex architectures, and time-changing shape and properties. 4D printing is particularly interesting for the manufacturing of soft actuators with complex design, suitable for remotely-controlled manipulators, soft robotics, and reconfigurable optical systems. Despite such enormous opportunities, current additive manufacturing technologies are still far from being a robust fabrication platform for systems with embedded optical functionalities. This is especially relevant for fabricating 4D optical components and devices, which might enable a novel class of devices, that are recongurable and programmable by external optical signals. To this aim, an engineering of the 3D printing technologies for active and photoresponsive materials is needed, allowing for going beyond the consolidated current printing methods, developed mainly for passive optical materials. The present thesis aims to design photoresponsive actuators through the combination of 4D printing, experimental activity, and numerical simulations. The devices consist of polymer cantilevers printed by fused deposition modelling (FDM) and functionalized by photochromic molecules. The approach here developed allows printing mm-scaled levers that can be controlled by utilizing external ultraviolet and visible laser beams, with characteristic actuation times of the order of a few seconds. The cantilever deflection upon external light control is characterized, evidencing fine control of the polymer beam positioning by varying the intensity of the control light beam. Finite elements simulations of the actuation process were carried out, and the results were compared with the experimental ones. The results of this study pave the way for a novel class of actuators, which are addressable precisely and remotely by light beams, thus advantageous in autonomous microsystems when an electrical energy source is not feasible.È consentito all'utente scaricare e condividere i documenti disponibili a testo pieno in UNITESI UNIPV nel rispetto della licenza Creative Commons del tipo CC BY NC ND.
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https://hdl.handle.net/20.500.14239/21475