Prediction of vibroacoustic transmission characteristics through double-plate floor structures by using finite-difference time-domain analysis

Abstract

A vibroacoustic numerical method employing a finite-difference time-domain (FDTD) method, in which the target floor structure consisting of a floor panel supported by support legs on a floor slab is modeled as a composition of two-dimensional plate elements for the double plate structure and one-dimensional bar elements for the support legs, is proposed. While floor impact sound is difficult to accurately predict owing to the complexity of the vibroacoustic mechanism influenced by the coupling phenomena with the vibration of the double-plate structure connected by support legs and the sandwiched air layer between the double plates. In this paper, the basic theory of the proposed numerical scheme was validated through comparison with excitation test on an acrylic scale model, and the applicability of the method to a practical case of a vibroacoustic transmission via a two-layered floor structure was discussed through a numerical case study.

Finite-difference time-domain simulation of floor-impact sound excited by one-dimensional contact model and its application to auralization of floor-impact sound

“…Firstly, the Masses 1 and 2 were set as 8 and 92% of the entire weight of the whole body as in [33]. Secondly, the spring coefficient, k heel , of the Mass 1 (heel part of the sneaker) was estimated as k heel ¼ EA=L [13], where E is Young's modulus, A is the contact area of the heel, and L is the thickness of the rubber of the sneaker sole. Then, k heel , was set to 1:06 Á 10 6 N/m by using the following parameter values: Young's modulus was set to 4:6 Á 10 5 N/m 2 assuming the hardness of the rubber of the heel to be 50 deg., A was set to 46.4 cm 2 assuming the surface area of the heel of the sneaker to be 20% of the entire area of the rubber sole, and L was 0.02 m. On the other hand, the leg stiffness of 13.91 kN/m obtained by Coleman et al [34] was adopted to model the excitation force by Mass 2.…”

“…On the other hand, structure-borne sound transmission characteristics can also be numerically predicted by statistical energy analysis (SEA) [3][4][5], finite-element method (FEM) [6], and finite-difference time-domain (FDTD) method [7][8][9][10][11][12][13]. Particularly in the prediction by the FEM and FDTD methods, the floor-impact sound is predicted on the basis of discrete numerical schemes.…”

“…Particularly in the prediction by the FEM and FDTD methods, the floor-impact sound is predicted on the basis of discrete numerical schemes. In most cases, the excitation characteristics caused by various types of impactor are modeled using mathematical functions such as the Gaussian function [13]. On the other hand, some research studies for modeling the excitation characteristics of the excitation devices for heavyweight floorimpact sound measurement have been conducted [14][15][16].…”

Numerical simulation of floor impact sound excited by one-dimensional contact model

“…On the other hand, structure-borne sound transmission characteristics can also be numerically predicted by statistical energy analysis (SEA), finite-element method (FEM), and finite-difference time-domain (FDTD) method [3]. Particularly in the prediction by FEM and FDTD method, the floor impact sound is predicted on the basis of discrete numerical schemes.…”

“…Particularly in the prediction by FEM and FDTD method, the floor impact sound is predicted on the basis of discrete numerical schemes. In most cases, the excitation characteristics caused by various types of impactor are modeled by some mathematical functions such as Gaussian's [3]. On the other hand, some research studies for modeling the excitation characteristics of the excitation devices for heavyweight floor impact sound measurement have been conducted [4].…”