Response to 'Comment on 'A lightweight yet sound-proof honeycomb acoustic metamaterial'' [Appl. Phys. Lett. 107, 216101 (2015)]

摘要

We thank Peiffer et al. for their comments on our paper and the opportunity to clarify the following points in our work: (1) Peiffer et al' first pointed out that the impedance tube sound transmission loss (STL) results of our metamaterial cannot be directly scaled up to a large size sample in a diffuse sound field. We agree with the authors' viewpoint, and indeed, we made no such claim that these two results are identical. The authors conducted simulations of a simply supported sandwich specimen (face-sheets + honeycomb) to show the difference between a small sample and a large sample. For the small sample, very large STL can be observed at low frequencies (stiffness-controlled region) below the resonance frequency of the sandwich specimen. For the large sample, since the resonance frequency reduces dramatically, the large STL at low frequencies disappears. The authors, however, neglected the most essential part of our material, i.e., the membrane, which introduces the "local resonance." This can be seen from Fig. l(a) in Ref. 2, the resonance frequency due to the membrane (where the STL dip occurs) is at around 1160 Hz. Figure 4 in Ref. 2 further shows that this STL dip frequency did not change significantly after adding the facesheets.