Optimal Functionally Graded Cellular Materials (FGCMs) to Mitigate Shock and Impact Loading
Abstract
The main objective of the proposed work is to develop a well-defined, experimentally-validated material model that can be implemented in the design of an optimal functionally graded cellular materials (FGCMs) that can effectively mitigate shock and impact loading. First, different density foams with known cell size and structure will be investigated to improve our understanding of the failure processes that are activated in cellular materials subjected to high strain rate loading. The specimens will be subjected to controlled, high strain rate impact and shock loading conditions while using multi-scale imaging and digital image correlation to (a) observe the local deformation processes, (b) quantify the local deformations and strain that are present and (c) quantify the inertia and change in local densities that are experienced by the heterogeneous cellular material system. The observations and measurements will be integrated with a non-parametric method to quantify the full field stress-strain relation of the material across the specimen section by accounting for effect of inertia, strain rate, and change in density. The constitutive relation obtained experimentally will be used to develop a material model that governs the response of cellular materials subjected to high strain rate loading as a function of density and loading rate. Finally, using the constitutive relationship and a semi-analytical method, a range of FGMC topologies will be explored to obtain an optimal design for functionality. In this proposal, the PI will focus on the shock and impact mitigation functionally and the optimal design will be selected through e1Y- a; absorption and efficiency-diagrams. The concepts proposed for this study can be extended to other functionality, including thermal acoustic transport properties. If successful, the work will have a significant contribution to the effort to innovate material and structures that absorb energy, deflect penetration and disperse momentum, processes that are crucial for the mission of the US Army. It is well aligned with ARO mission to understand the fundamental behavior of cellular materials under different loading conditions so that optimal FGCMs can be designed to protect warfighters from the effects of high rate loading conditions and shock loading. Furthermore, the proposed method can be used to develop and validate FGCM material models as well as providing benchmark data for future developments. The proposed research is ideal for the PI s future research plans to characterize multifunctional materials, soft materials, biological materials and their dynamic behavior. Since the proposed research involves different tasks and requires different expertise (i.e, material science, experimental mechanics, computational mechanics), it will provide a platform for personal development while also encouraging collaboration with experts in key areas, including US Army scientists and investigators. The proposed work is also ideal to supporting the PJ s long-term education and research plan, especially participating undergraduate students in his research. The proposed study contains a broad range of activities such as digital imaging correlation, high strain rate experiment, multi-scale measurements, microstructure characterization, analysis of failure and constitutive behavior, effect of strain rate and analytical and numerical simulation which is ideal to educate future scientists, graduate and undergraduate students, with different disciplines and techniques.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 07, 2018
- Source ID
- W911NF1810023
Entities
People
- Addis Kidane
Organizations
- Army Contracting Command
- United States Army
- University of South Carolina