Structural Acoustics and Materials Development

The work will be performed by Pennsylvania State University~s Applied Research Laboratory(ARL Penn State).Task 1 Background, Technical Approach, and MetricsUnder recent ONR funding, the Sierra software of Sandia National Laboratories was identified asviable HPC software to adapt for Navy structural acoustics. The software was expanded in keyareas by ARL Penn State for use in (heavy fluid) structural acoustics calculations and is currentlybeing evaluated for use in full-ship acoustics simulations.Some of the techniques used under the current effort were identified as enablers for a timedomainboundary element capability that is valid for very large motions and large transientevents, and that may offer a computational advantage to the commonly used frequency domainapproach. This capability was developed and partially validated under the current funding. Whatremains is to demonstrate the capability and its strengths for very large models such as a full-shipmodel.In the proposed effort, ARL Penn State shall continue evaluation of the revised Sierra softwarewith emphasis on full-ship simulations to identify frequency range limitations balanced againstcomputational hardware requirements. ARL Penn State shall conduct research to characterizethe capabilities and limitations of the novel transient boundary element solver recently developed. Emphasis will be placed on the practical use and demonstration of capability for theNavy structural-acoustic analyst end user. The Technology Readiness Level (TRL) will beinherently assessed through regular comparisons against currently used methods for performingstructural acoustics simulations for Navy-relevant systems. Simulation times and validity ofresults will be key metrics used in the evaluation of the TRL.Interactions: A Non-Disclosure Agreement with Newport News Shipbuilding is in place to sharemodels and results for evaluation of the HPC software for a full-ship simulation.Task 2 Background, Technical Approach, and MetricsARL Penn State shall continue to advise graduate students in topic areas relevant to Navystructural acoustics. Currently, a doctoral candidate is performing research on the transmissionof unsteady stresses caused by a turbulent boundary layer through a surface-mounted elastomerlayer. Scholarly research in the above example is critical to improving first principle modelingcapabilities that will be inherently required for future Navy vessels that may deviate fromconventional design practices.Topic areas for a future student will be suggested by ARL Penn State to ONR for concurrenceprior to commencing research. ARL Penn State shall seek highly qualified students with interestin careers working with the Navy, which will compound the benefit of the research to the Navy.The student researcher shall perform a literature survey to assess the current state-of-the art in theagreed-upon research area, which will serve as the baseline against which technologicalimprovements will be compared. The TRL shall be assessed through comparisons with currentNavy practices and through verification and validation of any newly developed techniques and/orcapabilities.