Accession Number:

ADA439875

Title:

Ordered and Highly Scalable Granular Media for Shock Mitigation

Descriptive Note:

Final rept. Jun 2004-Apr 2005

Corporate Author:

ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE

Personal Author(s):

Report Date:

2005-09-01

Pagination or Media Count:

67.0

Abstract:

We provide an update to our current efforts in studying shock mitigation using one-dimensional arrays of adjacent metal spheres that may progressively shrink in size. These tapered chains are characterized by the number of spheres, N, the amount of tapering, q, and restitutive losses, . Spheres are assumed to interact via the nonlinear Hertz potential, V 52, where is the amount of overlap of adjacent grains and the constant of proportionality varies with the material. To gauge the ability of such chains to absorb transient pulses, we look at the normalized kinetic energy, KEN, as a function of N, q, . A hard-sphere approximation and numerical analysis is therefore performed for 3 d N d 20 and 0 d q, d 0.1 for two tapered chain architectures. Intended experimental studies are outlined as those that have already been performed and focus on solitary wave propagation in monodisperse q 0 chains. Results are quite encouraging and independent of system size consequently, we propose a tapered chain armor panel design consisting of many tapered chains working in tandem. The specific and gravimmetric absorbed energies are calculated for an example prototype. Intended work and further discussion are provided in the conclusion.

Subject Categories:

  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE