Air force 14. 1 Small Business Innovation Research (sbir) Proposal Submission Instructions

PHASE I: Develop prototype process/material and evaluate feasibility of proposed approach.

PHASE II: Refine the prototype process/material based on lessons learned in Phase I. Validate final process/material configuration in a production representative environment. Provide assessment of process/material benefits relative to the baseline technology.

PHASE III DUAL USE APPLICATIONS: The developed process/material could be directly applied to airfoils and structural parts required in the commercial aviation market.

REFERENCES:

1. R.C. Reed, The Superalloys: Fundamentals and Applications, Cambridge University Press, 2006.

KEYWORDS: aerospace castings, thin walled castings, solidification stress

AF141-152 TITLE: Uncertainty Quantification in Modeling and Measuring Components with Resonant

Ultrasound Spectroscopy

OBJECTIVE: Define, develop, and execute an uncertainty analysis for the multi-physics modeling of the variation in resonant ultrasound spectroscopy (RUS) frequency due to damage accumulation in Ni-base superalloys.

DESCRIPTION: To be able to model accurately the resonant effect of multiple conditions (both material and geometry-based) simultaneously, propagation of uncertainty, due to model, material and measurement “errors”, must be well understood. The application of numerical simulation models to quantify the variation in resonant ultrasound spectroscopy frequencies of Ni-base superalloy material subject to macro/microscopic damage raises questions as the confidence of the model results and what can be done to improve this confidence? Uncertainties may have many different sources or drivers. Some of these uncertainties are model related and some are parameter related. To be able to model accurately the resonant effect of multiple conditions simultaneously, uncertainty quantification and error propagation must be well understood.

PHASE I: Identify sources of systematic errors that affect the accuracy and precision in the RUS estimation due to model, material, and measurement. Perform sensitivity analysis of how the uncertainty in outputs can be allocated to different sources of uncertainty in inputs. Derive confidence limits to describe where the true value of the variable may be found. Identify areas of focus for Phase II.

PHASE II: Work with actual components to validate the conditions modeled in Phase I. Match measured resonances with modeled resonances to examine errors. Utilize other methods to examine variation. Generate or obtain samples demonstrating variation in microstructure and/or dimensions. Examine alternate RUS hardware configurations in Design of Experiments (DOE) format to examine effects of sensor variables.

PHASE III DUAL USE APPLICATIONS: Develop system prototype RUS inspection system and demonstrate in an production environment.

REFERENCES:

1. Uncertainty Propagation in Analytic Availability Models, Amita Devaraj, Kesari Mishra, Kishor S. Trivedi, 2010 29th IEEE International Symposium on Reliable Distributed Systems, pg 121-130.

AF141-153 TITLE: ITO Repair on Transparencies

OBJECTIVE: Currently, there does not exist an adequate ITO repair. Develop methods for the production of transparent conductive materials that are durable and easily applied for repair of scratches in ITO on transparent substrates.

DESCRIPTION: Indium tin oxide (ITO) is a traditional material of choice for conductive transparent coatings for use in many current and future Air Force applications. Applications include the dissipation of and shielding from incident energy and electrodes for display technologies, opto-electronic devices, and harvesting solar energy. While current technologies meet desired metrics for sheet resistance and transmittance[1,2], ITO is not durable, easily applied, or cost effective. During the lifetime of the ITO coating, scratches and nicks develop and begin to degrade its performance. Current repair processes use time consuming, labor intensive processes which are only temporary, and reduce visibility in the repaired area and tend to chip or peel off, which requires reapplication, and often the surrounding ITO coating is further damaged.
When the size of the damaged area increases beyond an acceptable level, the entire coating must be replaced, which is expensive and increases aircraft downtime. Currently, this repair process includes the removal of the entire transparency and shipment to specialized facilities wherein the coating is stripped and reapplied in large vacuum chambers which is very costly, wastes a large amount of indium and requires specialized equipment. Although this approach successfully returns the part in pristine condition, it also requires several weeks or months to complete, considerable maintenance, inspection and combat recertification, during which time the aircraft is out of commission. In addition to down time, Indium is an expensive element that has seen an enormous price increase in the last 10 years and is being utilized more and more by the electronics industry. Currently, there is not a domestic source for indium[3], and there is a desire to decrease reliance on Indium.
Alternatives to traditional ITO repair may include, but are not limited to, novel ITO manufacturing techniques that lower cost and time of large area deposition and allow depot maintenance, and non-ITO /Hybrid approaches such as polymer composites, thin single wall carbon nanotube/graphene networks, or thin films of inorganic/organic hybrids. Application techniques amenable to depot conditions (ambient temperature, humidity, pressure) are preferred and may include spraying, or rolling in order to fill scratches or gaps that are problematic in typical ITO coatings.
This project will develop the capability to produce filler material for scratch repair in current ITO coatings.
Potential commercial applications of this technology could include the repair of cellular phone or computer touch-screens, which also require continuous transparent conductive coatings in order to function properly.

PHASE I: Develop an ITO repair material and process that meets current metrics for ITO; ease of application, quick and seamless repair of damaged areas. Meet metrics for ITO, prove durable and flat (roughness <1 mil). Demostrate a repair on an area of 5millimeters by 20millimeters; easily applied for scratch repair.

PHASE II: Phase II will focus on increasing the production capability and demonstrate the effectiveness of the material. The deliverable in Phase II will be 1 kg of material and the demonstration of scratch repair of a series of ITO coatings meeting the above requirements without scattering or loss of continuity. The scratches should represent different depths and widths.

PHASE III DUAL USE APPLICATIONS: Qualify repair procedures for field applications.

REFERENCES:

1. F.F. Ngato, et al., “Deposition of ITO Films on SiO2 Substrates,” Applied Surface Science, vol. 248, pp. 428-432, 2005.

AF141-154 TITLE: Conformal Conductivity Probe

OBJECTIVE: To develop a tool capable of measuring the conductivity of coatings and gap fillers (sealants) on surfaces with complex curves.

DESCRIPTION: The current point inspection tool (Tier I) that is used to inspect electrically conductive coatings on the aircraft is a waveguide cavity probe. The probe is an open-ended waveguide of defined length, that is excited on the feed end through a circular iris. When the open end of the waveguide is placed on a flat conductive surface, a cavity is formed. The Quality Factor (Q) of the cavity is measured and the conductivity of the terminating wall is calculated. Errors are induced when the surface being inspected is non-planar due to leakage around the gap created by the waveguide and the curved surface being inspected. It is desirable to have a device that can measure the conductivity of coatings and gap fillers on mildly curved compound surfaces.
The measurement device should be capable of determining surface conductivity (ie: ohms per square) of conductive coatings and gap fillers. It is desirable to measure this within the 8-18 GHz frequency band, though not necessarily across the entire band. A single broad-band probe is highly desirable. The probe will be used on fielded air vehicles and cannot damage the surface being measured. The device should pose no safety hazard to personnel or equipment. It shall be capable of being approved for flight line operation. The surface will not typically be flat and therefore should conform to the surface being tested. Assume that the probe must accommodate surfaces from flat to a compound radius of curvature of approximately 50 inches. The equipment should also have the ability to support higher radii of curvature. The probe should be capable of measuring small areas to support gap filler inspection. A smaller footprint is desirable. It is anticipated that the probe will work in conjunction with a government furnished vector network analyzer. The analyzer is a two port instrument and it is desirable that the probe not require additional ports. A standalone device or one that utilizes special test equipment is acceptable. It is expected that this probe will be transportable and operable by a single technician. Considerations during the design of any equipment used for this end should include: robustness, hand held use in the field, and Class I, Div II certification.

PHASE I: Investigate concepts that may be applicable to non-destructive, in-situ evaluation of the electrical conductivity of gap fillers. The range of conductivity shall be between 0 to 10 ohms/square. It is be desirable for the technique performed through a thin dielectric coating. Demonstrate a measureable approach on a test panel with a 0.25" wide by 0.25" deep by >6" long filled gap.

PHASE II: Ruggedize equipment, workout commercialization issues, partner with any appropriate companies to ensure successful production, meet other needs of the user. Demonstrate hand-held, ruggedized version to be fielded.

PHASE III DUAL USE APPLICATIONS: This conformal conductivity measurement technology is expected to be used on military aircraft with conductive coatings and curved surfaces. Commercial use could include any measurement of electrical properties on curved surfaces.

REFERENCES:

1. Measuring the Resistivity of Bulk Materials, EE Times, Mary Anne Tupta (http://www.eetimes.com/ContentEETimes/Documents/tupta_eeteujan2011.pdf).

AF141-156 TITLE: Vibration Stress Relief

OBJECTIVE: Develop a repeatable technology to relieve stress in a weldment using vibration stress relief. The AF currently doesn't have many ways to repair large weldments and this process may provide the ability to repair major structural components.

DESCRIPTION: Vibration Stress Relief is gaining momentum in heavy industry as a way to reduce the residual stress built up during the welding process. If the processes currently established in industry can be shown to be mature, repeatable and controllable then the potential exists to perform on-airplane stress relief of weld repairs greatly increasing the reparability of the F-22 titanium frames and the forward and aft booms. Currently these structures cannot be weld repaired due to the required high temperature thermal stress relief process. Thus repairs often involve material removal and patches, causing more downtime and elaborate repairs.
This task could have great benefit to the customer in allowing them to perform on airplane weld stress relief. The US Department of Energy has said that vibration stress relief is a, "proven substitute to 80-90% of heat treat stress relief applications yet saves 65-95% of the time and cost in doing so without sacrificing quality!" A quick investigation of the Boeing Library indicates that it was last investigated in 1987 where it was shown to have promise but was not yet repeatable. Discussions with vendors indicate that the process has greatly matured in the subsequent 25 years [1-3].

PHASE I: Assess the reliability of a vibration stress relief (VSR) process to relieve the weld-induced stresses in a Ti-6Al-4V weldment using a reliable measurement technique, e.g., X-Ray diffraction, to characterize surface stresses before and after stress relief. Gauge R&R methods should be applied to both the process and the measurements to validate the VSR process effectiveness.

PHASE II: Expand the applicability of VSR to a broad spectrum of prototypical weld configurations / structural applications and develop a strategy to mature the technology to meet aerospace quality weld requirements at the fleet level. Demonstrate the effectiveness of VSR to improve the weld integrity to ensure improved mechanical performance and structural durability over untreated welds.

PHASE III DUAL USE APPLICATIONS: Develop and transition to industrial practice a validated, turnkey VSR process / system that can be applied to the weld repair of aerospace structural components to meet Air Force and OEM requirements. This should be demonstrated on real DoD or commercial hardware, e.g., Fighter Aircraft

REFERENCES:

1. A. Walker, A.J. Waddell and D.J. Johnston, Vibratory Stress Relief - An Investigation of the Underlying Process, Proc. Inst. Mechanical Engineers., 209, 51-58 (1995).

AF141-157 TITLE: Galvanic Corrosion Prediction for Aircraft Structures

OBJECTIVE: Develop a quantitative test method to characterize proposed material/material couple and a predictive tool to reliably identify the location/s and rate of galvanic corrosion for dissimilar materials/barriers under controlled environmental conditions.

DESCRIPTION: Predicting galvanic corrosion is a high priority for USAF aircraft system managers. However, there are currently no design trade tools available to aerospace engineers that effectively characterize the behavior of common airframe construction materials and account for their contributions to galvanic corrosion. Obtaining such a tool is critical during design of new aircraft structures as well as legacy airframe repair material selections as a means of moving from the philosophical goal of “find and fix” to a presumably more cost-effective “predict and manage.” This necessitates development of novel trade tools which can predict the galvanic corrosion-specific performance of common structural materials, fastening, and proposed barrier scheme/s. The tool will allow designers the ability to validate material selection, providing prediction and economical life cycle management of the weapon system.

PHASE I: Illustrate feasibility by developing and demonstrating a prototype tool to quantify material couples & predict galvanic corrosion. The materials will be bare aluminum (7050-T7451) & graphite epoxy composite. Quantitatively compare the tool with actual test data to reliably identify "hot spots." Quantitative analysis could include but not limited to weight loss, micrograms/cm2/year.

PHASE II: Implement best approach from Phase I into a prototype tool capable of quantifying and predicting galvanic corrosion in a representative mechanically fastened and/or bonded joint constructed from typical materials and processes. The AF is interested in a tool associated with 7050-T7451 anodized aluminum bonded with Hysol EA 9394 epoxy paste adhesive to graphite epoxy. Deliverable of final report shall include recommended practices for predicting galvanic corrosion for design of AF systems.

PHASE III DUAL USE APPLICATIONS: Phase III commercialization opportunities abound with aerospace manufacturers and DoD laboratories. Industry needs to ensure sustainable designs do not have undue corrosion while the sustainment methods maintainers incorporate do not lead to additional galvanic corrosion.

REFERENCES:

1. P. Poole, A. Young, and A.S. Ball, “Adhesively bonded composite patch repair of cracked aluminum alloy structures,” in “Composite repair of military aircraft structures,” AGARD-CP-550, October 1995, Paper 3.

(http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA293056#page=37).
2. H. P. Hack and J. R. Scully, “Galvanic Corrosion Prediction Using Long- and Short-Term Polarization Curves,” Corrosion, February 1986, Vol. 42, No. 2, pp. 79-90. (http://corrosionjournal.org/doi/abs/10.5006/1.3584889).
3. M. Mandel, L. Krüger, “Determination of pitting sensitivity of the aluminium alloy EN AW-6060-T6 in a carbon-fibre reinforced plastic/aluminium rivet joint by finite element simulation of the galvanic corrosion process”, Corrosion Science, 2013. (http://www.sciencedirect.com/science/article/pii/S0010938X1300125X).
KEYWORDS: corrosion, galvanic, bonded composite

AF141-158 TITLE: Durable, Low Friction Coating for Variable Speed Refueling Drogue (VSRD)

OBJECTIVE: Develop and demonstrate a durable coating that can be applied to the MC-130J’s VSRD outer ribs in order to increase the mean time between failures and reduce life cycle cost.

DESCRIPTION: The Variable Speed Refueling Drogue (VSRD) is used on the MC-130J to refuel helicopters with probe-and-drogue refueling systems. The program objective is to develop a sustainable, suitable, and cost effective aerial refueling drogue for the 37 MC-130J Commando II aircraft. The new VSRD system will be capable of supporting an airspeed envelope of 105-210 Knots Indicated Airspeed (KIAS), providing aerial refueling support for SOF CV-22 and rotary-wing platforms.