Experimental validation of a locally resonant metamaterial plate Javier Hernan Vazquez Torre, Jonas Brunskog, Vicente Cutanda Henriquez 1 Technical University of Denmark Ørsteds Plads 352, 2800 Kongens Lyngby In-Jee Jung, Jeong-Guon Ih 2 Korea Advanced Institute of Science and Technology 291 Daehak-ro, Yusung-gu Daejeon 34141, Korea ABSTRACT An analytical model for broadband sound transmission loss of a finite single leaf wall using a metamaterial was previously developed and validated numerically. It is of interest to validate the analytical model with experimental results. In this paper, the band gap (BG) behavior of a locally resonant metamaterial is tested and compared to the analytical and numerical results. First, the unit cell resonance is measured for four nominally equivalent samples and the material properties extracted. Then, vibration analysis of a finite metamaterial plate is carried out. The influence of the variability of the properties of the resonators due to the construction method is analyzed both experimentally and numerically. Lastly, the result is compared to the analytical model and conclusions drawn. The analytical model could not be fully validated with the experimental measurements, but the specimen exhibited BG behavior. The variability of the resonators has an important influence in the performance of the metamaterial plate. 1. INTRODUCTION Acoustic metamaterials (AM) are being studied extensively because of their novel properties not found in nature. The definition of acoustic metamaterials may be broadly interpreted as systems or materials that display (as a whole) extraordinary properties not found in natural materials with respect to sound and vibration characteristics, such as negative apparent mass and/or bulk modulus. [1–6]. They owe this behavior to internal subwavelength structures. One of the most important characteristics of the AM is the so-called band gaps (BG), a frequency region where wave propagation is not possible. This property shows great promise to be a good tool to be used in sound insulation, absorption, and even radiation [7–9]. Band gaps can be introduced into these structures by mounting an array of resonators to them. This type of construction has been studied and validated in recent years [1–6]. An analytical model for broadband sound transmission loss of a finite single leaf wall using a metamaterial was developed [9]. The analytical model is useful to better understand metamaterials composed of single degree of freedom resonators and how the different parameters affect their behavior. From the optimization process emerged the possibility of tuning the BG above the 1 jhevaz@elektro.dtu.dk, jbr@elektro.dtu.dk, vcuhe@elektro.dtu.dk 2 injee@kaist.ac.kr, j.g.ih@kaist.ac.kr