This study investigated the relationship between dynamic stiffness, thickness, and heavyweight floor-impact sound level for EPS resilient materials with 10 MN/m 3~3 0 MN/m 3 dynamic stiffness and 10 mm~30 mm thickness. As a result, the single-number quantity (SNQ) with a bang machine was 52 dB~57 dB, SNQ with rubber ball at 1.0 m height was 48 dB~52 dB, and SNQ with rubber ball at 0.3 m was 43 dB~48 dB. The relationship between dynamic stiffness and SNQ with bang machine was a negative correlation, and that with a rubber ball was a positive correlation. The floor impact sound level at 63 Hz showed a negative correlation with dynamic stiffness, and those at 125 Hz and 250 Hz showed positive correlations for all impact sources. The thickness of EPS resilient materials was negatively correlated with floor-impact sound level over 125 Hz for all impact sources. In addition, a design method of EPS resilient materials is discussed using a contour map of floor-impact sound level in terms of thickness and dynamic stiffness.

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A series of studies on the subjective response to aircraft, railway, and road traffic noise has previously been carried out. However few studies have examined the optimal physical parameters for this type of measurement and evaluation. To date, several physical parameters, such as the equivalent sound level (L eq ), day-night average sound level (L dn ), and day-evening-night average sound level (L den ), have been used to evaluate various types of transportation noise. However, physical parameters that are universally applicable to all types of transportation noise have not been developed. The present study was designed to analyze the relationship between transportation noise and the subjective response. The study is currently in the preliminary stages of developing a physical parameter that can evaluate both individual and combined transportation noises. In conclusion, the regression model, which includes a set of variables that describe sound levels for single and mixed source noise, predicts annoyance levels with an accuracy of >95%, as measured by the determination coefficient.