# Presentation: 657312

## Thermophysical Properties of PBX-9501 from Multiscale Modeling

**Thermophysical Properties of PBX-9501 from Multiscale Modeling**
*** ***
***Grant D. Smith***
***Tommy Sewell***
***Department of Materials Science & Engineering***
***Department of Chemical Engineering***
***University of Utah***
***Los Alamos National Laboratory***

## Collaborators: 

**Collaborators:**** **
_***University of Utah***_
***Dmitry Bedrov ***
***Oleg Borodin ***
***Chakravarthy Ayyagari ***
***Hemali Devande ***
***Ben Hanson***
***Liping Xu***
_***LANL***_
***Thomas D. Sewell***** **
***Kim Rasmussen***** **
***Scott Bardenhagen***
***Ed Kober***
** **

## PBX-9501 

**PBX-9501**** **

**PBX-9501 is a granular composite  material**

## Importance of PBX Thermophysical Properties 

**Importance of PBX Thermophysical Properties**** **

**Ignition and violence of thermal explosions are determined by thermal transport and PBX/product EOS**
**Ignition is determined largely by heat flux, pressure and temperature**
**Violence is determined by a balance between heat release from exothermic deflagration reactions, heat dissipation by thermal diffusion and HE/product volume and pressure**
**	**

## Important Properties 

**Important Properties**_** **_

**Heat capacity**
**Thermal conductivity**
**Thermal expansion coefficient**
**Compressibility and other mechanical properties**
**Phase changes and associated volumes and heats of transition**
**These properties of the PBX all depend (some strongly) upon thermodynamic condtions (T, P)**
**	**

## Properties of PBX-9501 from Simulation

**Properties of PBX-9501 from Simulation**

## MD simulations of HMX         

**MD simulations of HMX**_**         **_

******-HMX**

******-HMX**

******-HMX**

******liquid**

**	****A high-quality quantum chemistry based potential was developed and validated for these simulations**

## MD simulations of HMX         

**Calculations of thermophysical and mechanical properties of **
******-,********-,and ********-HMX over a wide range of P and T.**

**MD simulations of HMX**_**         **_

|  |  Exp. |  |  |  |
| --- | --- | --- | --- | --- |
| C11 | 20.8 | 22.2 | 30.6 | 14.5(C11=C22) |
| C22 | 26.9 | 23.9 | 23.3 | 14.0 (C22=C11) |
| C33 | 18.5 | 23.4 | 31.4 | 18.0 |
| C44 | 4.2 | 9.2 | 0.80 | 4.4 (C44=C55) |
| C55 | 6.1 | 11.1 | 3.3 | 4.4 (C55=C44) |
| C66 | 2.5 | 10.1 | 3.3 | 2.3 (C66=C11-C12) |
| C12 | 4.8 | 9.6 | 5.7 | 10.0 |
| C13 | 12.5 | 13.2 | 13.8 | 10.6 (C13=C23) |
| C23 | 5.8 | 13.0 | 6.0 | 10.3 (C23=C13) |
| C15 | -0.5 | -0.1 |  |  |
| C25 | -1.9 | 4.7 |  |  |
| C35 | 1.9 | 1.6 |  |  |
| C46 | 2.9 | 2.5 |  |  |
| G
K  | 
      10-17 | 7.0 
15.5 | 2.4
14.3 | 2.9
12 |

## MD simulations of liquid HMX         

**MD simulations of liquid HMX**_**         **_

## Prediction of Binder Properties

**Prediction of Binder Properties**

**Properties of high-molecular weight polymers can be calculated using previously developed link between MD simulations and well-established theories**
_**MD input (low MW Binder):**_
**Characteristic ratio**
**Monomer friction**
**Density**

## MPM simulations

**Currently we represent PBX-9501 as composite of spheres or cubes with experimental size distribution**

**PBX-9501 property homogenization**

**Dirty binder**

**Large grains**

**Dirty binder**
**(64% volume fraction)**

**Large grains**
**(83% volume fraction)**

**2 mm**

**0.05 mm**

## MPM simulations

**PBX-9501 property homogenization**

## Input from MD to MPM

**Dynamic mechanical properties, EOS, thermal transport, phase behavior **