Development of vertical incident sound insulation simulation technology using finite element method and application to lightweight core

If the octet truss core, which is a space filling structure of half regular octahedrons and regular tetrahedrons, has excellent sound insulation characteristics, the possibility of using the octet truss core is sufficiently widened. From this fact, we have studied to obtain sound insulation characteristics of the flat plate and the plate with single core using acoustic tube by the finite element method (FEM) with high accuracy. The calculation of sound insulation performance by FEM was limited to the qualitative study so far. For example, the correction is required due to the difference from the theoretical value, and the magnitudes of the correction values differ depending on the test pieces. In this study, we considered the incident wave and compared the sound insulation calculation result by the FEM calculation using the non-reflective boundary at the rear end of the sound receiving room with the theoretical calculation. As a result, both calculation values were almost the same. Therefore, it can be said that when the magnitudes of the incident wave and the reflective wave are almost equal, a quantitative study is possible. Taking advantage of this fact, in this paper the sound insulation characteristics of the plate with single core are compared with that of flat plate, and the effects of the sound insulation characteristics by the aspect ratio of the core are examined.