Research on the Sound Insulation Properties of Membrane-type Acoustic Metamaterials Jinyu Hao, Sheng Guo, Jian Cheng, Zhaopin Hu and Hongyu Cui E3S Web Conf., 252 (2021) 02028 Published online: 23 April 2021 DOI: 10.1051/e3sconf/202125202028