Jongkwan Ryu

1. 서 론 우리나라는 고령화 사회에 진입하였으며, 2024년 65세 이상 고령인구는 993만 8천 명으로 전체 인구의 19.2%를 차지하고 있다(Statistics Korea, 2024). 이러한 고령자 인 구의 급증에 따라 국가적 정책과 제도 수립이 활발히 이루 어지고

The rubber ball impact sound has been standardized by ISO 10140 series and ISO 16283-2 for laboratory and field measurements, respectively. The ISO 10052 standard specifies a survey method for the impact sound measurement using a tapping machine and a rubber ball. This study proposed measurement position for the survey method which is highly correlated with result based on the Korean Standards (KS) and the building regulation of South Korea for engineering method. The rubber ball impact sounds were measured in 79 reinforced concrete apartment houses, which have a centre point and four perimeter points for both exciting and receiving sounds. The proposed survey method was validated for only a specific type of apartment building layout and construction in the South Korean environment. The excitation and receiving points in the perimeter having the most similar characteristics to the results obtained using the Korean engineering methods were first selected. By combining the selected perimeter point and centre point for both the excitation and receiving sounds, the characteristics of each combination were compared with the results obtained using the Korean engineering method. When one excitation point or receiving point in the perimeter was added to the centre point for the proposed survey method, the difference between the measurement result using the engineering and proposed survey method decreased. The standard deviation of the difference between the SNQs of the proposed survey method and the Korean engineering method for measuring the rubber ball impact sound was smaller than 2 dB.

The exposure of a structure to an acoustic domain induces a sound field owing to the interaction of the air-fluid and structure at the acoustic–structure boundaries. It is difficult to predict sound pressure level through vibration mode, due to the acoustic mode of the coupling effect between vibration and sound in addition to the acoustic mode induced by vibration mode generated by external force. In this study, the acoustic mode induced by structural vibration modes were predicted through a numerical analysis. A finite element model of a reverberation chamber with a shell at one side was constructed, and modal parameters of the vibration and acoustic modes were evaluated through an eigenvalue analysis. In addition, the sound pressure generated by impact loading of the shell were predicted by vibration mode through a time-domain structure–acoustic coupling analysis. The vibration and acoustic modal responses were identified from the measured responses, and the acoustic mode associated with a specific vibration mode was examined. The results showed that the acoustic mode from the coupling effect was verified, and sound pressure prediction from vibration mode was possible if considered as the coupling effect. The proposed approach can be applied to predict the heavy-weight floor impact sound from the vibration of slabs in apartments.