방음구조 설계를 위한 이종금속 특수접합공법의 충격 소음 특성 분석

Abstract

Recently, a specific applied cladding method by rapidly accelerating cladder metal to the backer(the parent metal) using explosive energy enables each dissimilar metals welds overall surface. For its such chemical and physical advantage, It is used to the specific commercial and military purpose and domestic technical development is in progress recently. But The noise from blast has been provoking a complaints from the neighboring residents. So the necessity of blast noise assessment is raised prior to the explosion resistive and sound insulating structure design.

The scope of this study includes noise assessment by simulation, repetitive site measurement of impulsive sound of detonating more than 20kg of TNT-equivalent explosives and proposal of sound insulation design. The measurement configurated as 3 steps. The 1st step is test blast to determine the close measurement range and methode of 2nd step. The 2nd step is close blast test to determine blast sound source and the 3rd step is actual place blast measurement to obtain actual community noise countermeasure design.

According to those assessment described above, corrected noise prediction method of USBM equation suggested by National Environmental Dispute Resolution Commission, a government-affiliated organization of Korea, is not applicable to the studied type of impulse noise. If the sound source is properly determined, a general outdoor noise simulation software adopting ISO 9613 noise propagation calculation method is applicable to the impulsive sound prediction for community noise assessment. The time duration characteristics is similar to the that of impulsive sound described in ISO 10843. The dynamic pressure of blast is proportional to the distance from explosives and inversed cube root of explosive mass. The sound insulation design should focusd on the 16 Hz and 31.5 Hz, the measured peak frequency of explosion.

The suggested future study subject based on this study is defining the characteristics of semi-confined blast, development of low-frequency impulsive sound measurement and evaluation method and effective insulation of low-frequency impulsive sound including 16Hz and 31.5 Hz frequency range.