{'fraction_non_alphanumeric': 0.019319227230910764, 'fraction_numerical': 0.0036798528058877645, 'mean_word_length': 5.886075949367089, '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}}
Integrated impedance and guided wave based damage detection under temperature variation

Electro-mechanical impedances and guided waves have been widely studied for detecting localized structural damages due to their sensitivity to small structural changes. In this paper, an integrated impedance and guided wave (IIG) based monitoring system is developed to improve the detectability of various damage types under varying temperature. First, a hardware system, called the IIG system, was designed to achieve simultaneous measurements of electro-mechanical impedance and guided wave signals. Then, the effects of temperature on guided waves and electro-mechanical impedances were compensated using the passive imaginary part of the impedance signal. Finally, an automated damage classification algorithm which incorporates temperature compensation was developed. To validate the proposed algorithm, experimental investigations were performed for the detection of bolt loosening and crack in metallic structures subjected to the temperature varying condition, in the range of -20 to 70°C.