Measurement and Analysis of Sound Insulation Properties in Acoustical Wall Panels Used in Ships

Abstract

This thesis adresses the challenge of predicting sound insulation properties of cabin walls onboard a platform supply vessel. The sound reduction index is predicted using the softwares WinFLAG and Odeon, thus comparing theoretical results to on site measurements. In addition a method of measuring flanking paths between adjacent rooms is to be developed and tested. The sound reduction is calculated in WinFLAG, then used as input data in Odeon. Development of a method to measure flanking paths is based on a sound impact source. This impact source consists of a pendulum with a steel ball being released into the partition wall, causing vibrations in the structure that could be measured in a receiving room. A more complex wall type had been installed than originally thought, and the simulations done in Odeon were not applicable to the sound insulation measurements. However, new calculations in WinFLAG were explored and compared to the measurements. The comparisons show that WinFLAG does not cover such complex structures, but both WinFLAG and Odeon are effective programs that can be used to predict sound insulation, if correct information about the partition wall and rooms are provided together with a less complicated wall structure. The impact measurement method discoveres that this is a likely way of indicating flanking paths. The impact force is measured on different walls in the source room, and recorded in the receiving room. The results showed a clear difference between the impact force on the partition wall compared to the side and rear wall, displaying little sound traveling through flanking paths. When insulation measurements show poor reduction qualities, this impact method may be an easy way of checking if there are any interfering flanking paths.