본 연구의 목적은 전달함수법을 이용하여 비교적 간편하게 환경소음 저감용 방음벽 상단장치에 대한 성능평가를 수행하기 위함이다. 이를 위해 상단장치를 제작하고 임피던스관을 이용하여 투과손실 측정을 수행하였으며, 2 차원 경계요소법을 이용하여 상단장치에 대한 투과손실을 예측하였다. 실험결과 간섭 길이에 해당하는 상쇄간섭 주파수가 비교적 뚜렷하게 나타났으며, 측정결과와의 비교를 통해 성능예측기법의 타당성 검증 및 상단장치 내부 변경에 따른 음향성능 개선 모델을 제안하였다.
The purpose of this study is to easily perform the performance evaluation for noise reduction devices installed on the top of noise barrier by using transfer function. For this purpose, the noise reduction devices was made and the transmission loss test was performed by using impedance tube. And, the transmission loss for noise reduction devices was predicted by using 2D boundary element method. As a test results, the interference cancellation frequency according to the lattice length was clearly appeared. And, the acoustic performance prediction technique was verified by the comparison to the measurement results. Also, the improved model for acoustic performance was proposed according to the changes of internal structure of noise reducing devices.