Introduction:

A class of energetic materials known as reactive metal mixture (RMP) contain metal as the fuel and metal oxide as the oxidant (like Al/Fe2O3).

If RMP is synthesized with reduced grain size approaching 10 to 100 nanometers, we can bring the fuel and oxidant into close proximity. This will enhance energetic characteristics like burn rates and energy release rate. At the same time, nano grain size will also improve structural strength and result in a dual functional material with both structural strength and explosive power.

Objectives:

• To develop analytical, experimental, computational, and tools for the optimal design and synthesis of nano-structured multifunctional, reactive materials that simultaneously provide enhanced explosive power and structural strength.

A Potential DOD Application: Efficient and Small Size Target Penetration Missiles

B: High explosive material

A

B

A: Steel casing to be replaced by MESMsB: High explosive material

• Target Penetration Devices or Missiles (TPM) can destroy underground facilities by penetration through rock or concrete and then explode. Usually, high explosives (HE) are enclosed in a steel kinetic energy penetrator whose weight is usually many times HE.

• To increase the payload and thus increase explosive power, we can replace the steel casing by multifunctional energetic structural materials that has strength to penetrate through the target, and then react both HE and metal/metal oxide energetic composites.

• The additional strength is achieved through nanostructuring the energetic material and adding strength reinforcement.

Active Control of Buffet-Induced VibrationsHanagud 1

1. Develop a framework of oxidants and fuels to synthesize multifunctional energetic structural materials (MESM). Synthesize reactive metal/oxide particle (RMP) mixtures by two different novel sol-gel processes and a traditional mixing process.

Approach to the Proposed Basic ResearchHanagud 2

Sol Gel

NH4ClO4

CHx

Sol Gel

NH4ClO4

CHxoxidizer

fuel

1. Develop constitutive equations, reaction characteristics, stress-induced reaction criteria by using (a) ab initio procedures and molecular dynamics, (b) thermodynamic constitutive equation modeling procedure and (c) novel method of bridging length and time scales.

2. Establish failure theories and explosive reaction initiation criteria.

3. Tests to quantitatively characterize MESMs: parameters of constitutive equations, mechanical failure criteria, reaction initiation criteria, reaction kinetics/process and reaction products.

4. Design model target penetrating missiles (TPMs) with varying amounts of energetic structural materials or reinforced energetic structural materials.

5. Evaluate the design, and perform mechanical test on coupon samples (with and without fuel). Computational evaluation of the performance of designed TPM.

6. Impact and penetration tests of designed TPMs.

7. Post-test analysis of TPM without the fuel component (inert): microscopic analysis of sections of post-test penetrators.

8. Prediction of the performance of MESMs for other DOD applications.

1. Add additional strength reinforcement (RRMP) as found necessary at nano, micro and macro levels. Develop functionally graded materials for transition between RRMP and conventional structural materials.Develop methods to produce desired structural shapes of RMP and RRMP.

Research TeamMURI Participants: Georgia Tech: S. Hanagud (PI), D. McDowell, N. Thadhani, R. Tannenbaum, F. Mistree, A. Sexana, M. Zhou, M. Li, and J. Allen; VPI: R. Batra; Univ of Florida: L. Vu-Qouc; Florida State Univ: A. Stiegman; Univ of Maryland: W. Fourney and J. Cardenas-Garcia

Matching Fund Participants: MURI participants will work in cooperation with AFRL scientists: W. Wilson, M. Hughes, O. Toness, M. Dilmore, R.Armstrong and Krammer; and Lawrence Livermore Laboratory scientists: J. Satcher,A. Gash.

Interactions: through a secure website & video conferences

Task InteractionsCritical experiments for Strength,

Constitutive Equations, Reaction Initiation, and Reaction Process on RMP and RRMP

Reinforcement Concepts

Ab Initio and Molecular Dynamics Modeling, Constitutive Equations,

Bridging Scales for Multifunctional ESMs

Material Tests and

Model Validation Tests Synthesis of Multifunctional Energetic Structural Materials

Design of Model TPM& Numerical Simulations of

Designed TPMs

Optimization for Multifunctionality & Reactivity

in RMP & RRMPFracture Characteristics and Improvement of Fracture Toughness

Tests of TPMs without Fuels Tests of TPMs

with Fuels

Analysis of Recovered Penetrators

Predictive Equations, Procedures for Munition Designs,

& Procedure of ESMs

Hanagud 3

1. A framework for the selection/design of reactive metal/metal oxide mixture (RMPs) that can facilitate manufacturing different multi-functional energetic structural materials

2. Synthesis procedures of selected RMP

3. Methods of reinforcing RMP to produce multifunctional energetic structural material (MESM) for strength and energetic characteristics

4. Strength and energetic characteristics of MESM

5. Establishment of the link between MESM and their use in DOD applications, including missiles

6. Method of design of a model target penetrating missile (TPM) using MESM to increase the energy released from the current levels

7. Procedure for the analysis of the model TPM, test article, testing and validation for impact/penetration

8. Discussion of other potential DOD applications

9. Training of graduate students, including doctoral students

10.Training of minority students

11.Building an infrastructure for future research.

Expected ResultsHanagud 4