{'fraction_non_alphanumeric': 0.014649190439475714, 'fraction_numerical': 0.0015420200462606013, 'mean_word_length': 5.240384615384615, '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}}
Use of laser vibrometry to perform principal components analysis on structural intensity: theory and example

The notion of vibratory energy flow has developed at the end of the 70s. The utilization of finite difference techniques between a set of sensors (accelerometer, strain gauges or laser vibrometers) has allowed to develop usable formulations in beams and in plates. Other methods, other types of structures have been considered thereafter. The interest of the vibratory intensity concept is double: it uses first of all energy magnitudes that have the advantage to be common to waves of different nature and to different propagation media, finally, it possesses a vectorial nature that is able to provide an imagery of transfer phenomena in complex structures. However this last point is less evident than for the acoustic intensity: the confinement of mechanical structures and the multiplicity of sources of excitation is often going to reduce the practical utilization of the vectorial characteristic. For example, several independent or partially correlated sources are going to produce at a point components of different orientation whose resulting vector will not be able to show transfers of energy. In the extreme case, results are going to compensate, until to cancel the vector.