Concerns with terminologies and test methods related to material characterization and simulation

Sound package development in the transportation industry has taken a very different role in the past two decades. Instead of relying totally on measurements, acoustic engineers are relying on various numerical methods to characterize the acoustic performance of materials as well as predicting the interior noise levels and other products in the transportation industry. In doing these analyses, often one needs some measured data of different variables such as thickness and air flow resistance properties of an insulation material, and insertion loss properties of materials used for sound blocking purposes. This paper presents an overview of different standards and specifications that are often followed to measure and estimate these required input values.  Results obtained using different methods are not always comparable with each other and therefore have the potential to obtain incorrect conclusion. The paper provides some case studies of inconsistent results because of that.