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Corrosion Nondestructive Evaluation (NDE) in Confined Access Areas

Description:

OBJECTIVE: Develop and demonstrate a man-portable capability to rapidly assess the presence of corrosion on the exterior sides and bottom of an in-ground large scale box-like steel structures with access to only the interior surfaces. Quantify thickness loss and identify other possible corrosion types such as pitting, fretting, and/or exfoliation, and integrate the capability to analyze any trends in the material loss as a function of spatial location and geometry of any detected corrosion in the material. Automatically generate a report that can be exported via a non-proprietary software interface and/or translated into a neutral format (e.g. ranging from binary to HDF5) enabling input to a digital data storage system. 

DESCRIPTION: The Air Force has secure underground vault storage systems some of which have been in the ground for over 20 years and have experienced variable temperature and/or humidity environments. These storage systems are typically comprised of a large area steel box that is lined along its exterior with concrete. Access to the interior surfaces of the structure is possible by removal of the lid to the steel box. Access to the external surfaces of the structure is not possible. Currently, there is no capability to rapidly assess the internal condition of the steel structure except via a qualitative visual assessment. The capability being sought includes the ability to use NDE methods to determine the presence of corrosion in the steel material (both exterior and interior surfaces), map the thickness loss as a function of location, and track these losses as a function of each inspection. The data needs to be collected and exported via a non-proprietary format to simplify its translation into a digital data storage system. 

PHASE I: Phase I shall demonstrate the feasibility of an NDE-based system that can measure a minimum of 20 percent thickness loss (threshold) / 10 percent thickness loss (objective) for a large scale representative steel structure with an accuracy of 10 percent (threshold) / 5 percent (objective) of actual thickness loss. The demonstration should be supported by modeling as necessary and must be demonstrated on representative corrosion (e.g. real corrosion, artificially induce corrosion, and/or simulated corrosion). The system must show potential to assess 600 square feet of area in 1 hour or less. The approach must include methods to make the system relatively light and easily wearable for the inspection process (threshold is less than 30 lbs). It is preferable that the system be battery powered and not require battery changes for the duration of the inspection of each steel structure. The system must include an approach for spatially mapping the location of corrosion and storing this information via an automated reporting function that is exportable in a non-proprietary data format. 

PHASE II: Phase II shall demonstrate a prototype system that can meet the objectives specified for the Phase I and demonstrate the integrated corrosion thickness loss tracking system with an automated reporting capability. It is anticipated that final demonstration will occur at a government facility to be determined during Phase I to ensure the system can meet all required performance parameters in a representative working environment. The targeted operator for this system is an Airman with application specific training (i.e. NDE qualified – AFSC 2A7X2) therefore it must be shown to be able to be operated by such individuals with minimal additional specialized training. 

PHASE III: Similar storage systems with limited access exist in analogous Military and commercial structures. The desired capability will have applications to assess the presence of corrosion in similar liners and related geometric configurations in a rapid and quantitative manner. 

REFERENCES: 

1: D.S> Forsyth, Nondestructive Testing for Corrosion, available at https://www.researchgate.net/profile/David_Forsyth/publication/268275867_Chapter_21_-_NON-DESTRUCTIVE_TESTING_FOR_CORROSION/links/551ab3ae0cf2fdce84369861/ Chapter-21-NON-DESTRUCTIVE-TEST

2:  Busse G., "Emerging Technologies in Non-Destructive Testing". Proceedings of the 4th International Conference of Emerging Technologies in Non-Destructive Testing, Stuttgart, Germany, 2-4 April 2007 Taylor & Francis, London, 2008.

3:  G.C. Moran and P. Labine, Eds, Corrosion Monitoring in Industrial Plants using Nondestructive Testing and Electrochemical Methods, ASTM Special Publication 908, ASTM International, Philadelphia, PA, 1986.

KEYWORDS: Non-destructive Inspection, Destructive Inspection, In-ground, Steel-reinforced, Concrete Structures 

CONTACT(S): 

Matthew Hartshorne 

(937) 255-4108 

matthew.hartshorne.1@us.af.mil 

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