Since the introduction of microperforated (MP) sound absorption elements more than 40 years ago many variations of noise control devices from room acoustics to induct applications have been manufactured based on this technology.
It has been demonstrated that micro-perforated elements can provide adequate IC-engine gas exchange noise attenuation. Several exhaust and inlet system silencers incorporating micro-perforated elements have been presented during the past 15 years for engine applications, encouraging the replacement of the typical fibrous materials and aiming several advantages including cleaner environment.
The acoustical characteristics of the MP elements, have been studied thoroughly by several authors and good analytical models exist to predict the attenuation performance of those elements. However, almost no published information can be found regarding the reliability of the MP elements utilized in harsh engine exhaust system environment.
In this paper the reliability of stainless still MP element designed for small engine exhaust systems is critically studied, with the focus on the durability of the acoustical performance.