| Abstract [eng] |
This dissertation investigates the dynamic characteristics of additively manufactured (AM) structures and develops an effective vibration control methodology by integrating macro fiber composite (MFC) actuators to suppress their vibration amplitudes. To achieve this, polylactic acid (PLA) and PLA-based composite structures including PLA reinforced with short carbon fibers (PLA-SCF), continuous carbon fibers (PLA-CCF), and continuous glass fibers (PLA-CGF) were fabricated with both unidirectional (0°–0°) and cross-ply (0°–90°) layer orientations. The influence of layer orientations on the dynamic characteristics (natural bending mode frequencies, bending mode shapes, amplitude spectrum, and damping) of each AM structure was investigated. Vibration amplitude suppression was then performed on these structures by applying a vibration control methodology using MFC actuators, identifying the orientation and structure exhibiting the maximum vibration suppression. Additionally, the effect of the signal phase (ranging from 0° to 360°) applied to the MFC actuators on the vibration amplitude was examined, and the phase that provides the maximum vibration suppression for each AM structure was determined. Non-destructive C-scanning was conducted to identify internal defects in the AM structures using the THz spectrometer (TPSTM Spectra 300 THz Pulsed Imaging and Spectroscopy from TeraView). Finally, a finite element based numerical simulation approach has been developed to study dynamic characteristics and vibration suppression behaviour of the AM structures using MFC actuators. The trends of the simulation results were thoroughly compared and validated with experimental results. |
