Computer-Aided Tool for Wrapping Periodic Elements onto Doubly-Curved Surfaces

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Directed Energy (DE); Advanced Materials The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. OBJECTIVE: The next generation of airborne platforms will make extensive use of planar periodic electromagnetic structures to manipulate various electromagnetic interactions with surfaces of an air vehicle. In almost all cases, it is desired to wrap these structures over the complex and irregular surfaces of these air-vehicle platforms. However, conforming planar periodic structures over doubly-curved and irregular surfaces causes the planar periodic electromagnetic structures unit cells to become deformed, which alters their electromagnetic properties in an undesirable way. The objective of this topic is to develop a general-purpose software tool that can wrap any planar periodic structure over any surface while minimizing or eliminating any of the unit cells from being deformed. The tool shall use solid models as inputs and outputs to maximize compatibility with other software. DESCRIPTION: Future warfighting includes an incredibly complex, contested, and often hostile electromagnetic spectrum environment through which our airborne platforms will operate. Planar periodic structures can be employed to manipulate electromagnetic interactions with the surface of a vehicle. To utilize / cover the full surface area of a platform without any gaps, it is desired to wrap the periodic structures over irregular and doubly-curved surfaces [1]. Unfortunately, doing this also deforms the unit cells of the periodic structures, which alters their electromagnetic properties. In recent years, several algorithms have been demonstrated with the ability to bend, twist, conform and otherwise spatially vary periodic structures in a special way that minimizes unintended deformations to the unit cells [1,2]. These algorithms have been used to wrap frequency preferred surfaces over doubly-curved surfaces while preserving the electromagnetic performance of the unit cells [1]. Such periodic structures can be called preservational spatially-variant lattices (PSVLs). It is desired to create a general purpose software tool that can wrap any planar periodic structure over the surface of any object in a way that preserves the size, shape and spacing of the unit cells, all using solid modeling. Meshes are highly problematic because they can contain many errors, such as being non-manifold (e.g. not air tight), and they are less compatible with commercial CAD and simulation software. The inputs and outputs of the Phase II software tool shall be solid models to maximize compatibility with other software and avoid errors that arise when manipulating meshes. PHASE I: In Phase 1, the performer shall conceptualize a software tool that offers a user the capability to wrap any planar periodic structure over any surface as a PSVL. The software tool shall take as inputs solid models of the unit cell and the surface over which to generate the PSVL. The performer shall lay out a software tool development strategy for implementation during the Phase II effort. PHASE II: The Phase II effort shall develop and demonstrate a software tool that offers a user the capability to wrap any planar periodic structure over any surface as a PSVL. The software tool shall take as inputs solid models of the unit cell and the surface over which to generate the PSVL. The software tool shall export a solid model of the PSVL that can be directly and easily imported into manufacturing and simulation software. Any proposals using meshes as inputs or outputs will not be considered for funding. The Phase II software shall provide a modern user interface. The performer shall address how the PSVL software could be parallelized for computationally intensive jobs, operated in secure cloud environments suitable for DOD and defense contractors, and connected to manufacturing software during a Phase III effort. PHASE III DUAL USE APPLICATIONS: Operating air platforms through complicated and hostile electromagnetic environments is a high priority for the Air Force. The Phase III will focus on complete maturation and commercialization of the technology including a user-friendly interface and integration with manufacturing software. REFERENCES: Valle, Cesar L., Gilbert T. Carranza, and Raymond C. Rumpf. "Conformal Frequency Selective Surfaces for Arbitrary Curvature." IEEE Transactions on Antennas and Propagation (2022); Digaum, Jennefir L., et al. "Tight control of light beams in photonic crystals with spatially-variant lattice orientation." Optics express 22.21 (2014): 25788-25804.; KEYWORDS: Planar; conformal mapping; periodic structures; spatially-variant; electromagnetics; irregular surfaces; planar periodic electromagnetic structures.