Experimental and numerical investigation of defect modes in periodic expansion chamber mufflers

Autor(es)

Goto, Adriano M. ; Monteiro, Wanderson V. de O. ; Dos Santos, Jose Maria C.

• Tipo de documento: Artigo Científico
• Fonte: MECHANICS RESEARCH COMMUNICATIONS; v. 148, p. 14-pg., 2025-09-01.

Resumo

Phononic Crystals (PCs) remain a prominent research topic in vibration and sound control. PCs are artificial materials constructed from a periodic arrangement of unit cells exhibiting high impedance variation. This periodicity can provide remarkable properties. For sound control problems, the expansion chamber muffler (ECM) can be analyzed as a PC structure when its acoustic performance is periodically enhanced, thereby promoting bandgaps. However, these properties maybe affected by a disruption in periodicity, which occurs when some geometric parameters exhibit variation. Such disruption leads to the emergence of an additional mode within the bandgap region, referred to as a defect mode. The present study investigates the effects of periodicity disruption in an ECM structure and the influence of each geometric parameter of the ECM silencer. The two-dimensional transfer matrix (2D-TM) method is implemented to compute the response under geometric variations. Dispersion diagrams, transmission loss, and frequency response function curves are numerically evaluated and experimentally validated for multiple scenarios. The results show that the ECM is highly sensitive to certain geometric parameters, which can significantly influence the acoustic performance of these silencers due to defect modes. (AU)

• Processo FAPESP: 19/16794-2 - Atenuação sonora em arranjos periódicos de dutos e painéis micro-perfurados
• Beneficiário: Adriano Mitsuo Goto
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 18/15894-0 - Projeto e otimização de estruturas periódicas para aprimoramento de desempenho vibroacústico
• Beneficiário: Carlos de Marqui Junior
• Modalidade de apoio: Auxílio à Pesquisa - Temático