TECHNOLOGY AREA(S): Materials/Processes, Weapons

ACQUISITION PROGRAM: PMA 201 Precision Strike Weapons

OBJECTIVE: Develop a non-invasive and non-destructive way of evaluating concrete strength of material properties and behavior along with relevant spatial and statistical information associated with them.

DESCRIPTION: Building materials such as Conventional Strength Concrete (CSC), High Strength Concrete (HSC) and Ultra High Performance Concrete (UHPC) may vary significantly from their intended design specifications in terms of their strength of materials behavior and intrinsic material properties, along with their spatial distribution.� Deviation is to be expected given variation in mixing materials, workmanship, and other quality assurance considerations from the processing of these building materials.� Despite these variations, the Navy needs the ability to confirm/dispute these physical and strength of material parameters on the as-built and cured object and provide uncertainty bounds with respect to the original material specifications.� Currently, this capability is limited to selected laboratory strength of materials estimates, which are seldom relatable to inherent material models useful to the Navy. Given these challenges, there is a need for an innovative, non-destructive, and non-invasive solution that allows the Navy to assess the different strength of materials and intrinsic properties associated with cured and/or previously built concrete structures.

The solution must be capable of assessing objects made with concrete (CSC, HSC, and UHPC) that may take the form of complex geometrical structures, slabs, columns/cylinders, cubes, concrete cores, and other bulk geometries to include full sized structures.� It must be a combination of non-invasive and non-destructive hardware sensors and corresponding analysis software capable of evaluating a concrete sample/object and confirm the strength of material properties along with other intrinsic properties of said object with associated uncertainties and spatial distributions.� Intrinsic properties of interest include, but are not limited to: density, sound speed, bulk compressibility, and Specific Heat Capacity at constant volume.� Strength of material properties include, but are not limited to: Bulk, Young�s and Shear modulus, Poisson�s ratio, Yield Strength, Ultimate Strength, and Unconfined Compressive Strength.

The design must be clearly focused on quantifying the data needed to populate property values useful in defining an Equation of State, Strength of Material, and other Constitutive/Damage models such as that defined by the Holmquist Johnson Cook (HJC) Concrete.� All data must be useful for inclusion into high-performance hydrocode material model definitions and be outputted as variable pair values data in a clear text file along with a graphical depiction through the software solution.

The proposed solution must be able to operate in two potential scenarios�an internal laboratory assessment and a field deployment whereby the out-of-laboratory hardware/sensor solution must be portable (total size and mass not to exceed 6 cubic feet and 20lbm).� Additionally, it must be capable of being operated by one test engineer in the field.� The field-capable hardware/sensor solution must be ruggedized to applicable Military Standards (similar but not limited to MIL-STD 810) and be able to temporarily store all of the data sensed/captured internally during the sample�s evaluation phase.� Sensing of the physical and strength of material property data during an out-of-laboratory scenario must not take longer than 15 minutes per measurement and allow for a quick assembly and disassembly time of not more than 15 minutes respectively.� A visual or graphical depiction of the data collection and completion process must be included in the proposed solution for both the laboratory and field systems.� Data collected in this field deployment scenario and parameters computed therefore must be within 15% of those collected and parameters computed in a laboratory for the same material/sample/core.� No hardware/sensor size nor weight constraint are instituted for the laboratory scenario allowing for a higher fidelity assessment of the data collected therein.

The hardware/software calibration features must be available prior to a sample�s evaluation phase for both envisioned scenarios and take no longer than 30 minutes for both.� For both scenarios, the hardware/sensor solution must be able to communicate to a portable laptop computer and allow compatibility with Windows and Linux Operating Systems (OS).

The software/analysis compliment for the solution must be able to analyze concrete objects (or sections of an object) that vary in total mass from 1lbm to 200 tons and thicknesses ranging from 5 inches to 25ft for the field deployment scenario, while the laboratory sample scenario must be able to analyze similar components ranging in total mass from 1lbm to 100lbm, and thicknesses ranging from 5 inches to 4ft.

The software/analysis solution must process the data collected in either scenario, and deliver results within 30 minutes allowing for a visual output of the data with information regarding the spatial distribution (two- or three-dimensional) and uncertainty bounds/calculations.� The solution must include clear instructions (e.g., user�s manual or similar) covering calibration, setup/configuration, and post-processing of the data collected in order to properly obtain desired results.

PHASE I: Identify and evaluate potential technologies/methodologies applicable for the solution.� Demonstrate the feasibility of a preliminary design of the hardware, software, and methodology solution, including identification of necessary resources.� Create a preliminary engineering development plan along with an evaluation of potential numerical methodologies and calibration plans to include potential ruggedization of the field-deployable version.� In addition, create a proposed Graphical User Interface (GUI) design for the analysis software, analysis logic flow, and computational development plan.� An assessment on which of the parameters are useful in populating a HJC-Concrete material model would be quantified, and an evaluation of the methodology used in ascertaining the intrinsic and strength of material/constitutive/damage properties.� The Phase I effort will include prototype plans to be developed under Phase II.

PHASE II: Develop a working prototype to include applicable testing of the suite of hardware/sensors.� Demonstrate the performance of the proposed solution in both in-field and laboratory scenarios with comparison of the output data from using more traditional strength of material concrete testing.� Complete analysis software and demonstrate in the post-processing of various concrete samples/objects that range in size.� Demonstrate spatial assessment of the strength of materials as well as other physical properties useful in building an HJC-Concrete material model along with the establishment of uncertainty bounds on the data/model values.� Deliver source code, design specifications, engineering layouts, configuration, and user�s manual for Government evaluation.

PHASE III DUAL USE APPLICATIONS: Transition hardware and software solution to the U.S. Navy for use in daily analysis of concrete structures/objects.� Receive feedback from users and release updates addressing feature requests and bug fixes.� Enhance the visual and graphical capabilities useful in future assessments.� Document and incorporate enhancements into solution updates.� Complete a Verification and Validation report for the entire solution along with its associated modules/packages.� Deliver updated hardware and software solution along with final user�s manual.� Commercial applications involve DoD contractors supporting the Tri-Service community, the Department of Homeland Security, the U.S. Coast Guard, Federal Bureau of Investigation, and Federal Highway Administration supporting their different concrete quality assurance and evaluation efforts.

REFERENCES:

1. Wight, James K. and MacGregor, James G. �Reinforced Concrete: Mechanics and Design, 7th Edition.�� http://www.chegg.com/textbooks/reinforced-concrete-7th-edition-9780133485967-013348596x http://www-pub.iaea.org/MTCD/publications/PDF/TCS-17_web.pdf

2. �Guidebook on non-destructive testing of concrete structures.� Training course series No. 17. International Atomic Energy Agency, Vienna, 2002. http://www-pub.iaea.org/MTCD/publications/PDF/TCS-17_web.pdf

3. Helal J., Sofi, M. and Mendis, P. �Non-destructive testing of concrete: A review of methods.� Special Issue of the Electronic Journal of Structural Engineering 14(1) 2015. http://www.ejse.org/Archives/Fulltext/2015-1/2015-1-9.pdf

4. Holmquist, Johnson and Cook. 14th International Symposium on Ballistics, 1993 Vol.2, pages 591-600.; Warhead Mechanisms and Terminal Ballistics. 1993

KEYWORDS: Concrete; Ultra-high Performance Concrete; Model Development; Noninvasive; Strength of Materials; Hydrocode