# Vibro-Acoustic Numerical Simulation for Analyzing Floor Noise of a Multi-Unit Residential Structure
###### Abstract  
In South Korea, the construction of new multi-unit residential structures has been continuously increasing in order to accommodate multiple households in single structures. However, the presence of walls and floors shared with neighbors makes these structures exceptionally vulnerable to floor noise transmission when the noise of everyday life occurs. In particular, South Korea has many social problems associated with such floor noise, which require the utmost attention and immediate resolution. In this study, a 17-story structure was selected as a test structure. Field measurements were carried out. A numerical model for the 17-story structure was developed in order to perform a vibro-acoustic analysis. The validation of the numerical model comparing with the field measurement data results shows a good agreement. Finally, it is concluded that numerical analysis can be applied to resolve floor noise problems arising in multi-unit residential structures.  
f Ams  
system, so the finite element approach costs are excessively high, and so in this case, statistical- and energy-based methods (e.g., SEA) are broadly used in this range. The intermediate domain between the low and the high frequency has a feature of complexity whereby the low- and high-frequencies behavior coexist, and for that reason, a hybrid deterministic-statistical method is recommended [14].  
It should be noted that the FEM was considered to be an expensive numerical tool for room acoustics simulations with complex boundary conditions, and so the application of the method was limited to low-frequency regions. However, the situation has been changed rapidly owing to the outstanding progress of computational power and the development of efficient elements and methods. Therefore, the application of the method is no longer restricted in predicting the sound field in a residential structure at the high-frequency regions [3; 4; 8; 9; 10; 11; 12].  
Vibro-acoustic analysis has been applied to solve structural acoustic problems. [PERSON] et al. investigated the effects of finite dimensions on the vibro-acoustic response of orthogonally stiffened panels. Three types of excitations, such as acoustical excitation, point force excitation, and random excitation, were considered. Their models were compared with numerical simulations and experimental results in order to complement them [16]. [PERSON] et al. performed vibro-acoustic modeling and simulations using the finite element and the boundary element methods to determine the vibratory and acoustic properties of engine structures, such as the mode shapes and natural frequencies contributing to engine structure vibration [17]. [PERSON] and [PERSON] conducted a vibro-acoustic modeling and analysis of a rectangular acoustic cavity bounded by a flexible panel. Three modeling techniques, such as FEM, SEA, and a hybrid FE-SEA method, were considered. Finally, comparisons were carried out to validate the models and verify their accuracy using experimental results [18].  
In this study, the FEM is considered to utilize vibro-acoustic analysis, which is the concurrent operation of structural vibration and acoustic noise analyses. To utilize a numerical analysis to solve floor noise problems, a numerical model for residential buildings must be constructed. Then, a vibration analysis must be performed, so that the results can be used as inputs to the noise analysis, i.e., acoustic analysis.