OBJECTIVE: Find a reliable and inexpensive way to define UHPC component damage due to multiple loading events of penetration and blast. Develop appropriate engineering aids/software defining structural capacity due to incremental abnormal loadings events (e.g., multiple air strikes) taking into consideration the differences in response of UHPC when compared to normal strength concrete. DESCRIPTION: DoD needs to develop the ability to efficiently and effectively assess damage and evaluate the residual strength (structural capacity) of UHPC structural components with compressive strengths in excess of 30 ksi, and similarly escalated tensile and bending strengths, to airblast, fragments, and munition penetrations. Currently, damage predictions require a baseline assessment of vulnerability at a pristine state and an a priori understanding of the localized damage evolution and prevalent boundary conditions of the structure at each incremental loading stage, such as occurs in a multi-strike event. A multi-strike event is defined as a repeated abnormal loading of a structure or its components. A continuous definition of the residual capacity of damaged components and structures is extremely important for weaponeering multiple layered hardened targets, and could be exceptionally helpful in planning protection from sequenced terrorist attacks or follow-on abnormal loads such as extreme wind and hurricane conditions. PHASE I: Phase I should clearly demonstrate the ability to quantify (or define) the resistance (or damage) of component/structure of the pristine and damaged UHPC in a minimum of two dimensions. A clear Phase I to Phase II decision point must be part of the final delivery in Phase I along with a roadmap that takes the program through Phase III. PHASE II: Phase II must demonstrate a methodology for evaluating damage and pertinent engineering level aids/software describing evolutionary damage and residual strength/structural capacity due to multiple abnormal events and disassociated of continuous testing or analyses. The Phase II final report should include a development plan and partnering approach for follow-on production and fielding along with a roadmap that takes the program through Phase III. PHASE III DUAL USE APPLICATIONS: PHASE III should include identification of support for commercialization of the developed product to predict the remaining strength (residual strength) of UHPC damaged by penetration and blast. The software should be able to specify which parameters are important to resist damage for use in architecture, engineering, and construction industries for economical but robust construction of the military and civilian sectors. Its application should include protective panels, structural elements (such as roofs, walls, slabs [shells, plates], beams, columns, and piles), and facilities (such as bunkers, nuclear power plants, and airport runways). The software also should consider predictions of remaining strength due to abnormal loadings from seismic, hurricane and tornado events. REFERENCES
Keywords: Uhpc, Blast, Penetration, Strength, Damage
