Air force 17. 1 Small Business Innovation Research (sbir) Phase I proposal Submission Instructions

PHASE I: Develop materials and optical isolator device designs for operation at 1µm and/or 2µm. Options include new magneto-optic materials or improvements to existing materials. Experiments shall indicate adequacy of the materials to meet the specifications given under the Description.

PHASE II: The contractor shall develop fabrication techniques for constructing all-fiber optical isolators with the specifications listed in the Description.

PHASE III DUAL USE APPLICATIONS: Military applications: airborne high energy lasers for aircraft self-defense Commercial applications: laser welding, laser cutting, and laser drilling.

REFERENCES:

1. D.E. Zelmon, E.C. Erdman, K.T. Stevens, G. Foundos, J.R. Kim, and A. Brady, “Optical Properties of Lithium Terbium Fluoride and implications for performance in high power lasers,” Applied Optics 55 (2016), 834-837

2. L. Sun, S. Jiang, J.D. Zuegel, and J.R. Marciante 1, “All-fiber optical isolator based on Faraday rotation in highly terbium-doped fiber,” Optics Letters 35 (March 1, 2010), 706-708

KEYWORDS: optical isolator, magneto-optic materials, high Verdet-constant materials

AF171-109

TITLE: Structural Directed Energy and Nuclear Effect Mitigation of Composite Aeroshells for Munitions

TECHNOLOGY AREA(S): Nuclear Technology

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 section 5.4.c.(8) of the solicitation and within the AF Component-specific instructions. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. Please direct questions to the AF SBIR/STTR Contracting Officer, Ms. Gail Nyikon, gail.nyikon@us.af.mil.

OBJECTIVE: Development, scale-up, and demonstration of munition relevant composite structural aeroshell materials designed to provide protection from directed energy, nuclear EMP, and nuclear particle effects.

DESCRIPTION: New material concepts are required for structurally integrated directed energy, nuclear electromagnetic pulse, and high energy nuclear particle protection for organic matrix composites. Directed energy for the purpose of this topic is defined as High Power Microwave (HPM) and High Power Laser (HEL) technologies. Nuclear particles for the purpose of this topic are defined as hot and cold x-rays, gamma rays, and neutrons. Materials submitted for consideration should be specifically designed for use on composite munition systems. Methods for incorporating the proposed materials into standard manufacturing processes such as braiding on a mandrel must be addressed. Protection materials must be incorporated into the structural buildup, not secondary applied or require additional non-standard manufacturing processes to fabricate.

New systems will require compliance with MIL-STDs, including 461, 464, and 3023, to meet the ever-changing mission environment. The metrics defined in the unclassified portion of the listed MIL-STDs will be used as evaluation criteria for the Phase I. Proposals to this topic must address the gaps in current composite materials’ ability to meet requirements such as those in the MIL-STDs list above. Relevant testing methods and techniques can be found in the "The Nuclear Matters Handbook, Expanded Edition" Appendix G4.1.[3] Proposed performance claims must be accompanied with supporting information or citation of available open literature or DTIC references. Materials proposed must be shown to be producible in large quantities, affordable, maintainable, and sustainable. Transition plans should include detailed discussion of material integration methods, cost relative to baseline materials, and maintainability/sustainability. Coordination with prime vendors and letters of support demonstrating the proposed transition pathway is highly encouraged.

Historically, technical efforts have focused on providing just one of the characteristics above; i.e. just HPM protection or just neutron protection. In this effort the composite must simultaneously provide protection from multiple directed energy and nuclear events while maintaining a weight near that of current composite material. Materials solution which add greater than 20% weight by volume over baseline composites

PHASE I: Propose, develop, and demonstrate flat coupons of scientifically relevant size (12 in. x 12 in. min.) to measure the performance of the composites under neutron, hot and cold x-ray, and directed energy environments. A design of experiments with specific materials and layups should be proposed, not just a review of the literature.

PHASE II: Build and demonstrate complex shapes of scientifically relevant size, in representative configurations, to measure the performance of the composites under neutron, hot and cold x-ray, and directed energy environments. Material should be a down selection from the design of experiment in Phase I. Specific platform based guidance and geometry will be provided in Phase II by the government.

PHASE III DUAL USE APPLICATIONS: Demonstrate the materials from the Phase II in a relevant environment and work with appropriate program office for transition and ground based simulated flight testing. Potential dual-use applications include shielding aircraft and spacecraft from cosmic radiation and electromagnetic environments.

REFERENCES:

1. MIL-STD-464: http://everyspec.com/MIL-STD/MIL-STD-0300-0499/MIL-STD-464C_28312/.

2. Nuclear Survivability Overview, DTRA:
http://www.dtic.mil/ndia/2011CBRN/Franco.pdf.

3. The Nuclear Matters Handbook, Expanded Edition:

KEYWORDS: directed energy, DE, HPM, HEL, munition, electromagnetic pulse, nuclear, high power microwave, composite, organic matrix composite, BMI, epoxy, ceramic, ceramic composite, polymer matrix composite, carbon fiber, astroquartz

TECHNOLOGY AREA(S): Materials/Processes

OBJECTIVE: Develop an additive manufacturing process capable of writing micron-scale features for frequency selective surfaces.

DESCRIPTION: For the protection of radio frequency (RF) systems from high-powered microwave (HPM), devices are being developed that require high-resolution features on the order of 3-5 microns. Thus far, photolithography has been the method of choice for the fabrication of these devices, using non-flexible substrates, such as silicon or glass. However, the use of inflexible substrates dictates that the devices are more readily placed into the near-field of the RF antenna where they may negatively affect the performance of the system, rather than into the far-field on a radome. Additive manufacturing is being explored as a method of integrating HPM countermeasures directly into or onto radomes. The radomes may be ceramic matrix composites (CMC) or polymer matrix composites (PMC), and the radome material and its operational environment dictate the material that can be written onto it. In the case of the CMC, which is used in high temperature applications, the FSS material must be capable of operation in the same environment as the CMC. For PMC radomes, the temperature requirements are less stringent and a larger variety of materials may be used. In high temperature applications, materials such as platinum cermet are used for the FSS. For PMC radomes, silver or copper based inks may be used. Inkjet, aerosol jet, and syringe pump direct-write are current state-of-the-art methods being used for depositing conductive traces but these methods have a realistic limit of 20-30 microns. Additionally, inkjet and syringe pump systems cannot write conductive traces conformally. Proposals are being sought to develop a technology which may utilize fully additive or a combination of additive and subtractive methods to create patterns with features and gaps of 3-5 microns. In a subtractive system, lasers may be capable of etching 10 micron gaps. While the basic requirement is for a system capable of meeting the specified resolution, the ability to perform the process conformally is beneficial and facilitates the creation of the patterns on radomes or other curved surfaces. This is a secondary requirement that may be addressed in successive phases of the SBIR. However, proposals for direct-write systems capable of conformal writing are preferred.

PHASE I: Phase I of this project would result in a design for an AM system with improved resolution over current capabilities. The objectives may be accomplished through an improvement/modification to a current technology or through a new methodology. The phase I would also result in the delivery of samples created on test equipment.

PHASE II: Phase II of the project will be the fabrication of a prototype system with a targeted 3-5 micron feature size. For cost purposes, this may be a system designed for the fabrication of two-dimensional patterns. A suitable demonstration of the device’s capabilities will be to fabricate a two-dimensional frequency selective surface. Samples of materials fabricated on the prototype will be deliverables.

PHASE III DUAL USE APPLICATIONS: Phase III of the project will be the fabrication of a prototype system capable of depositing a conformal pattern onto a radome or complexly curved surface.

REFERENCES:

1. A. Mette, P. L. Richter, M. Hoteis, S. W. Glunz, “Metal Aerosol Jet Printing for Solar Cell Metallization,” Published online in Wiley InterScience, 5 April 2007.

2. B. King, M. Renn, “Aerosol Jet Direct Write Printing For Mil-Aero Electronic Applications,” Published online

KEYWORDS: Directed energy, high powered microwave, direct write, additive manufacturing, radio frequency

AF171-111

TITLE: Nondestructive Quantification of the Degraded Elastic Modulus and Poisson's Ratio of Impact Damaged Polymer Matrix Composites

TECHNOLOGY AREA(S): Materials/Processes

OBJECTIVE: Using single-sided inspection(s), nondestructively quantify the degraded elastic modulus and Poisson’s ratio in an impacted Polymer Matrix Composite (PMC) with a spatial accuracy of 0.01 in. and estimated properties NTE ±5% of those found via traditional mechanical testing.

DESCRIPTION: USAF methods to ensure aircraft structural integrity is maintained throughout designed service life are based on Damage Tolerance as defined in MIL-STD-1530C. Damage tolerance requires adherence to fail-safe, slow damage growth (preferred), or in special applications, safe-life design criteria. For typical USAF structural alloys, damage tolerance is achieved primarily via integration of fracture mechanics with slow damage growth criteria. Nondestructive inspections are performed at prescribed intervals during in-service operation to ensure adherence to the damage tolerance criteria, and ultimately the safety of the aircraft. With increasing application as primary and secondary aircraft structural components, efforts have been focused on enabling a life management approach for composites similar to that employed for metallic structures. However, the current shortfalls in composite damage progression models and nondestructive characterization methods require USAF composite structures to be designed and maintained to a no growth criterion for specified damage morphologies. Thus, to enable damage tolerance via slow damage growth for composites, further development of modeling and nondestructive evaluation (NDE) methods is required [1].

A nondestructive testing technique is sought to measure the mechanical properties of an impact damaged graphite fiber reinforced polymer matrix composite for input to damage evolution models. Previous research has shown some success in nondestructive measurement of mechanical properties of carbon-carbon [2] and carbon-fiber reinforced polymer composites [3] by means of ultrasonic testing. Reconstruction of the impact damaged state of composites has also been investigated and reported in the literature [4,5]. The desired solution shall combine nondestructive measurement of degraded mechanical properties of impact damaged PMCs with a spatial map of the damaged region via single-sided nondestructive testing. The method shall be demonstrated on PMC panels of layup and impact damage similar to those found in reference [1] and must localize regions of degraded elastic modulus and Poisson’s ratio within a voxel of dimension 0.05 in. x 0.05 in. x 0.05 in. (threshold) 0.01 in. x 0.01 in. x 0.01 in. (objective). Further, the measured properties shall be accurate within a threshold of ±10% and an objective of ±5% of those found via traditional mechanical testing, and generated property values shall not rely on baseline subtraction. Output(s) shall be provided in a generic, non-proprietary format capable of implementation within any commercial or non-commercial simulation tool.

The nondestructive quantification of degraded elastic modulus and Poisson’s ratio of impact damaged PMCs will be instrumental in providing the needed robust, predictive simulation capability for damage evolution of composite structures. This capability is a key enabler for sustainment of current and future USAF aircraft – providing structural integrity engineers the foundation to confidently, safely, and effectively manage the fleet over its lifetime while alleviating the no-growth certification requirement, which may be leaving performance and weight savings on the table.

PHASE I: Using single-sided nondestructive inspection(s) of an impact damaged PMC, localize regions of degraded elastic modulus and Poisson’s ratio within a voxel of equally-sized edges: 0.05 in. x 0.05 in. x 0.05 in. (threshold) 0.01 in. x 0.01 in. x 0.01 in. (objective). The method shall be demonstrated on PMC panels of layup and impact damage similar to those found in reference [1].

PHASE II: Using single-sided nondestructive inspection(s) of an impact damaged PMC, quantify within a threshold of ±10% and an objective of ±5% the degraded elastic modulus and Poisson’s ratio localized within Phase I. The measured properties shall be verified against those obtained via traditional mechanical testing of the coupons employed in Phase I. Output(s) shall be provided in a generic, non-proprietary format capable of implementation within any commercial or non-commercial simulation tool.

PHASE III DUAL USE APPLICATIONS: Commercialize the tool/technique/method successfully developed in Phase II. Develop and document procedures for operation, calibration, and servicing. An example transition path is to partner with an AF system integrator to mature and demonstrate method in an operational environment.

REFERENCES:

1. D. Mollenhauer, E. Iarve, K. Hoos, M. Flores, E. Zhou, E. Lindgren, and G. Schoeppner “Damage Tolerance for Life Management of Composite Structures – Part 1: Modeling,” Aircraft Structural Integrity Program Conference, 2015.

2. R.A. Kline, G. Cruse, A.G. Striz, and E.I. Madaras, “Integrating NDE-derived engineering properties with finite element analysis for structural composite materials,” Ultrasonics 31, pp. 53-59, 1993

3. A. Castellano, P. Foti, A. Fraddosio, S. Marzano, and M.D. Piccioni, “Mechanical characterization of CFRP composites by ultrasonic immersion tests: Experimental and numerical approaches,” Composites: Part B 66, pp. 299-310, 2014.

4. J.H. Gosse, and L.R. Hause, “A quantitative nondestructive evaluation technique for assessing the compression-after-impact strength of composites plates,” Review of Progress in Quantitative Nondestructive Evaluation 7B, pp.1011-1020

5. A.A. Fahim, R. Gallego, N. Bochud, and G. Rus, “Model-based damage reconstruction in composites from ultrasound transmission,” Composites: Part B 45, pp. 50-62, 2013.

KEYWORDS: polymer matrix composites, impact damage, nondestructive evaluation, mechanical properties, composite damage progression modeling, aircraft sustainment

TECHNOLOGY AREA(S): Materials/Processes

OBJECTIVE: Develop thermal modeling capability to enable selection of heating, cooling, and insulation approaches to be used in conjunction, for on-aircraft curing of high-temperature repair materials while preventing damage to existing structure and systems.

DESCRIPTION: Greater amounts of aircraft structures are being fabricated from high-temperature polymer matrix composites (PMCs) (such as those containing bismaleimide (BMI) and polyimide resins), as evidenced by B-2, F-22, and F-35 aircraft. If components fabricated from these materials cannot be removed from the aircraft and original performance must be restored, repairs must utilize materials that cure at high temperatures. This cannot typically be accomplished using current fielded technology.

In order to achieve maximum structural/temperature capability for a PMC repair and return an aircraft back to full operational capability, repair materials must be cured within recommended temperature ranges. Not doing so can affect the crosslinking process in the resin (composite matrix or adhesive) and potentially lead to in-service failures by producing structurally weak patches and/or adhesive bondlines. A relatively uniform temperature distribution is desired across a repair area, but this is usually difficult to achieve since complex aircraft structure often contain thickness variations (due to composite ply drop offs) and have underlying substructure that result in “hot” and “cold” regions in the repair. Higher cure temperatures make uniformity more difficult to achieve. Additionally, elevated temperatures and long isothermal dwell times required to cure high-temperature PMCs and associated adhesives can be detrimental to surrounding structure, systems, and/or coatings.

To ensure a repair will be exposed to the proper temperature profile, thermal surveys of the repair area are typically conducted. These establish the low and high temperature regions and guide placement of heating units and insulation, as well as any active cooling required to protect surrounding structure or systems. A proper thermal survey is a time-consuming, iterative process that involves placing many thermocouples (often 100 or more) in a mock-up repair configuration to generate an accurate thermal map that will dictate location of the relatively small number of thermocouples to be used to control and monitor the actual repair, ensuring a proper thermal profile. The “hot” thermocouple must accurately reflect the highest temperature in the repair region and is generally used to set the maximum temperature for the repair (to prevent damage) and the “cold” thermocouple is used to determine the length of cure time.

In the past, there have been several attempts to develop lower-temperature-curing materials that can yield high-temperature service performance, but these have not been successful. Alternate curing techniques (e.g., ultrasonic, electron beam, microwave, induction) have also been evaluated as another way to address this issue, but they too have not been practical for real-world application. The traditional heating/cooling approach used for low-temperature repairs could be viable to successfully cure high-temperature PMCs if the repair area’s thermal profile and thermal response were understood to an extent much greater than can be practically achieved using thermal surveys alone. A thermal modeling capability is required to determine heating, insulation and cooling (amounts and locations) to achieve proper repair material cure temperatures for various structures while preventing damage to existing structure and systems. This model would also guide location of critical thermocouples necessary for monitoring and regulating the cure process. A relatively few thermal surveys could verify the model’s output for a given application.

Benefit of developing this capability would be to improve the performance and increase confidence in high-temp PMC repairs while reducing the time to effect a repair.

PHASE I: Develop a prototype thermal modeling system capable of accurately predicting the thermal profile of a small high-temp PMC part (with metallic backside structure) going through a simulated repair. This would entail heating the repair material and bondline to near 440°F while not allowing the backside structure to exceed 270°F during the cure cycle.

PHASE II: Demonstrate thermal modeling system on a representative PMC aircraft structure at least 4 square feet in area for a simulated 2-inch through-hole per the temperature parameters denoted in the Phase I above. Also need to show how the system is adaptable/versatile for different structures. Procedures/approaches for practical implementation of active cooling and heating using currently available COTS equipment should also be a part of the demonstration.

PHASE III DUAL USE APPLICATIONS: Military – for on-aircraft repair of high-temperature PMCs (BMIs and polyimides). Commercial – for Out of Autoclave and Autoclave processing of PMCs, specifically that the model can predict the thermal response of complex tooling utilized in the manufacturing of PMCs

REFERENCES:

1. FAA-H-8083-31 - Aviation Maintenance Technician Handbook - Airframe - Chapter 7: Advanced Composite Materials

2. "The Craft of Aircraft Repair", Composites World, May 1, 2005; compositesworld.com

KEYWORDS: Composites, BMI, PMC, polyimides, curing, thermal modeling, on-aircraft, repair

AF171-113

TITLE: Solid-State Amplifier/Transmitter replacements for Travelling Wave Tube (TWT) Technology

TECHNOLOGY AREA(S): Battlespace, Electronics, Sensors

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 section 5.4.c.(8) of the solicitation and within the AF Component-specific instructions. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. Please direct questions to the AF SBIR/STTR Contracting Officer, Ms. Gail Nyikon, gail.nyikon@us.af.mil.

OBJECTIVE: Increase availability, affordability, and reliability of amplifier components over current traveling wave tube (TWT) technology used in legacy missile warning/defense radars.