Impact Energy Dissipation through Force Chain Interruption
Abstract
The goal of this proposed research is to experimentally explore the mechanisms of impact energy dissipation by a granular media. The dynamic failure of granular particles in a force chain will be visualized with synchronization to the dynamic loading history. The effects of moisture on the particle failure will also be investigated. The results and physical insights developed in this proposed research are critical information for the effective utilization of natural materials in shock mitigation applications. Statement of the Problem: Granular (e.g., sand) materials are known to be effective in shock isolation and penetration resistant under ballistic impact loading conditions. These materials, which are widely available and affordable, may be utilized as construction materials for strategically important structures. To effectively employ these materials to defeat various threats of blasts and projectile impacts, design capabilities must be developed to evaluate and optimize the shock resistance of the structures. The reliability of such simulation-based predictive capabilities depends on the accuracy of material models fed into the simulation codes. This calls for accurate dynamic responses of all the materials involved in the impact events, including the granular materials. However, little is documented in the literature about the dynamic failure behavior of these materials. Systematic investigations on the fundamental impact failure mechanisms of granular materials must be performed to develop physical insights for material model development. We propose an experimental project that visualizes the dynamic damage/failure behavior of granular materials, synchronized with the loading history. Research Approach: To achieve the goal of this proposed research project, the proposed experiments will consist of three major portions: (1) The dynamic compression experiments on a string of granular particles will be conducted using a Kolsky bar and a gas gun integrated with high-speed X-ray phase contrast imaging at Beamline 32 ID-B of the Advanced Photon Source (APS) at Argonne National Laboratory. (2) The moisture effects on the dynamic damage and failure behavior of the granular material will be experimentally determined. (3) The mechanisms of impact energy dissipation through force chain interruption will be identified from the high-speed X-ray images and the associated loading histories. Significance of the Proposed Effort: A better scientific understanding of the dynamic energy dissipating behavior of granular materials will be developed through analyzing and understanding the high-speed real-time visualization obtained from the proposed dynamic experiments. The expected results of this proposed research program will significantly contribute to optimized design of strategically important structures. Physical insights learned in this research will lead to the development of innovative shock-mitigating materials.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 11, 2018
- Source ID
- W911NF1710146
Entities
People
- Weinong Chen
Organizations
- Army Contracting Command
- United States Army
- University of Virginia