TECHNOLOGY AREAS: Sensors, Electronics, Battlespace

ACQUISITION PROGRAM: PMA-290 - Maritime Patrol and Reconnaissance Aircraft

OBJECTIVE: Develop innovative tools and methods for converting and optimizing input structures of full wave electromagnetic solvers.

DESCRIPTION: Advanced electromagnetic solvers have proven an invaluable tool in analyzing RF sensor behavior on a variety of air and surface platforms. Given the cost effectiveness of these tools and the insight they provide to electromagnetic phenomena, we see their user base growing daily. The accuracy of a full-wave solver used to address these problems is directly tied to the input mesh quality. Input meshes for full wave solvers are either built manually using a geometric description of the platform and/or antenna as a reference or from an existing surface representation (e.g., Initial Graphic Exchange Specification or IGES) of the geometry of interest. Meshing tools generally create a good mesh for much of the geometry of interest; however, it is common for the meshing tool to produce low-quality mesh elements for a local area in the geometry. This is mainly due to the fact that most meshing tools are not optimized for electromagnetic problems, and some meshing algorithms have a fundamental limitation resulting in poor quality mesh elements. To compensate, the analyst can visually inspect the mesh and fix the problem areas by hand for small meshes. For a large mesh, fixing even a small percentage of the total mesh is a time-consuming task.

Innovative tools are sought that will examine an existing mesh, identify problem areas based on user specifications for edge length, aspect ratio, and connectivity, and then attempt to "fix" the mesh in the local area to meet the user’s requirements while maintaining the contour of the original mesh. After the mesh has been repaired, the tool should then identify any remaining problems and provide statistics to the user regarding the quality of the mesh.

Another problem with meshing tools that are not developed specifically for computational electromagnetics (CEM) is that they tend to generate meshes in certain areas that are much denser than necessary, resulting in many extra unknowns for the CEM solver. The proposed tool should also have the capability to isolate a section of the original mesh, where the density is higher than necessary, and generate a new, less dense mesh while preserving the vertices defining the boundary of the specified region.

PHASE I: Explore algorithms that will analyze an existing mesh and identify problem areas in the mesh based upon user specifications as well as determine if the mesh is open or closed. Research and explore algorithms for healing meshes. Determine proof-of-concept of techniques through tests on small and medium size meshes provided by NAVAIR. Investigate ideas for converting asymptotic solver meshes into full-wave solver meshes.

PHASE II: Using the most promising algorithms from Phase I, develop a prototype tool that will heal existing full-wave solver meshes and convert asymptotic solver meshes into full-wave solver meshes. This tool should include a graphical user interface (GUI) that allows the user to visualize the problem areas in the original mesh and provide statistics to the user regarding the original mesh and the healed or converted mesh.

PHASE III: Alone or with another company, develop a commercial strength gridding tool for CEM solvers.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: The tool developed in this project will find applications among commercial airframe builders, automotive industry, defense contractors, antenna houses, etc.

REFERENCES:
1. P. Lancaster and K. Šalkauskas, Curve and Surface Fitting. London: Academic Press, 1986.

2. J. F. Thompson, B. Soni and M. P. Weatherrill, Handbook of Grid Generation. Boca Raton: CRC Press, 1998.

3. V. D. Liseikin, Grid Generation Methods. Berlin: Springer-Verlag, 1999.

KEYWORDS: Mesh; Grid; Full-wave; Asymptotic; Computational Electromagnetics (CEM); Computer-aided Design (CAD)

** TOPIC AUTHOR (TPOC) **

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