{'fraction_non_alphanumeric': 0.016736401673640166, 'fraction_numerical': 0.0, 'mean_word_length': 5.493212669683258, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
An investigation into shape and vibration control of space antenna reflectors

A study into the shape and active vibration control of antenna reflectors, an important member of the space structures, is carried out in this paper. Geometric nonlinear analysis is considered for performance evaluation of antenna reflectors, as very high precision is an important aspect of space structures. An effort has been made to demonstrate the importance of functionally graded materials in space structures. Piezolaminated structures have been used for shape and vibration control applications for many years. However, due to the problems like debonding and delamination, the reliability of these materials in space structures is still uncertain. To overcome these problems, patches made of functionally graded piezoelectric material (FGPM) are used for shape and vibration control of antenna reflectors in this investigation. FGPM patches are also used to demonstrate the beam-shaping and beam-steering application of antenna reflectors. For the active vibration control application, a fuzzy-logic controller (FLC) is designed and validated with the experimental results. An experimental study has been conducted for comparing the performance of different controllers in the context of vibration reduction. The FLC is then used for active vibration control of an antenna reflector under the application of thermal impact and sinusoidal loading.