|Acquisition Program: |
| ||The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), which controls the export and import of defense-related material and services. Offerors must disclose any proposed use of foreign nationals, their country of origin, and what tasks each would accomplish in the statement of work in accordance with section 3.5.b.(7) of the solicitation.|| Objective: ||Develop analytical algorithms and numerical methods for the prediction of the structural response of concrete structures subjected to blast and fragment loading.
|| Description: ||There is a great interest in the defense community and in particular the U.S. Army Engineer Research and Development Center, Ref 1, in formulating theories and computational algorithms, which enable the accurate assessment of blast effects and fragment impacts on various types of concrete structures. These events are extremely complex and are relevant to a wide range of time and length scales. Novel multi-scale, multi-physics approaches in concrete modeling have shown great potential for simulating cracking and post-failure behavior of cementitious materials and, in general, quasi-brittle materials under a variety of loading conditions. The Lattice Discrete Particle Model (Ref. 2) has been demonstrated to be very suitable for simulating the fracturing process of conventional concrete and its post-failure behavior in a variety of loading conditions. However, many recent applications require the use of special concretes, such as Very High Strength Concrete (VHSC), Fiber Reinforced Concrete (FRC), etc. The modeling of these materials presents many challenges, because the scale of the aggregate can be very small and fiber-concrete interaction is very complex. Preliminary efforts in this area at ERDC have indicated that substantial effort needs to be placed in developing adequate analytical models for simulating the structural response of components made with these advanced materials.
|| ||PHASE I: Assess computational models for simulating VHSC, FRC, and other types of special concrete materials and cementitious composites in the context of a multi-scale, multi-physics, LDPM (Lattice Discrete Particle Model) framework. Identify shortcoming of current methodology and formulate a development strategy for future development. Characterize risk and potential payback of proposed modeling techniques. Perform some preliminary studies to compare the feasibility of new methodologies. Identify methods that should be implemented in a computational framework.
|| ||PHASE II: Implement methods identified in phase I in a computational framework. Improve efficiency of computational tools for the solution of very large problem on massively parallel computer systems implementing parallelization schemes. Improve robustness so that computational tools can be used reliably in a production environment.
|| ||PHASE III: Validate methods developed against experimental data. Application of the technology developed under phase II may benefit other areas in DOD as well as civilian agencies. Concrete materials are used in the construction of a variety of civilian structures, including bridges, dams, etc. Their response to extreme loading conditions is of extreme interest to the civil engineering community at large.
|| References: ||
1. U.S. Army Engineer Research and Development Center (ERDC) Broad Agency Announcement, ERDC, Vicksburg, MS. http://www.mvk.usace.army.mil/contract/docs/BAA.pdf
2. G. Cusatis, A. Mencarelli, D. Pelessone, and J. T. Baylot. “Lattice Discrete Particle Model (LDPM) for Fracture Dynamics and Rate Effect in Concrete”. Proceedings of the 2008 ASCE Structures Congress, April 24-26, 2008, Vancouver, Canada.|
|Keywords: ||concrete, numerical methods, fracture, blast, multi-scale, multi-physics|