A Finite Element-Based Acoustic Engineering Design Program for Advancements in Passive Noise Reduction Performance of Helmet Mounted Noise Defenders

The use of finite element analysis (FEA) modeling techniques to model both single hearing protection and double hearing protection noise attenuation will be refined during this Phase II program. Physically realistic, three-dimensional models ofcircumaural earcups and custom PVC earplugs will be created using the ABAQUS FEA software and coupled to fluid models of the ear canal geometries for a variety of users. The FEA model results will be made available for comparisons to MIRE test dataacquired for both single and double hearing protection device (HPD) combinations of the earcup and earplug devices. This project extends the successful Phase I project which initiated first-generation FEA model results. Those results were validated usingexperimental determinations of material transmission loss, vibration testing, and testing of both structural-acoustic and interior acoustic responses for the HPD configurations. The ultimate goals for the Phase II FEA modeling program are to finalizeprioritization of all noise attenuation mechanisms and to utilize the FEA models for identifying advanced state-of-the-art performance for HPD's. The anticipated benefits are the creation of a modeling data base the U.S. Navy can use for futureconsiderations of proposed revisions to circumaural headsets. The development of accurate FEA models will allow computational modeling, versus more expensive experimental investigations, of headset innovations proposed in future years. This will be asubstantial cost savings to the government. State-of-the-art headset technologies will be identified using the FEA modeling tools.