{'fraction_non_alphanumeric': 0.02080624187256177, 'fraction_numerical': 0.0, 'mean_word_length': 5.754385964912281, '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}}
Three-dimensional-printed membrane-type acoustic metamaterial for low frequency sound attenuation.

Membrane-type acoustic metamaterials have received much attention for low-frequency sound manipulation, especially in the form of decorated membrane resonators. In this paper, such resonators are obtained using fused deposition modeling. Beyond the practical aspects provided by this manufacturing method, the low density of the flexible filament used increases their effectiveness. Indeed, the mass usually added to the membrane center can easily be divided into several disjoint elements. Using rotary inertia of the added structures, new peaks of efficiency in both absorption and normal transmission loss appear when compared to usual decorated membrane resonators.