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VALIDATION OF THE ARMY BURN TO VIOLENT REACTION (ABVR) TEST AS A
TOOL TO PREDICT FULL-SCALE MOTOR RESPONSE TO FRAGMENT IMPACT
#20136
J. B. Neidert, M. A. Pfeil and J. A. Stanfield
Aviation and Missile Research, Development and Engineering Center
Redstone Arsenal, AL
ABSTRACT
While the ABVR experiment has been used rather extensively to investigate the
reaction mechanisms of rocket motors subjected to fragment impact, no efforts have
been made to validate that it truly represents how a full scale motor, with nitramine-
based propellants, would behave under similar circumstances. Thus, efforts are made
herein to validate the ABVR experiment by comparing the detonative response it
produces to those obtained in cylindrical experiments and analog motors. Results
indicate that the ABVR experiment is a valid sub-scale to predict the detonative
response of full-scale motors. The insight gained from the ABVR experiments has
resulted in a possible new screening tool during the development of new, insensitive
compositions.
INTRODUCTION
Since 1989, the Burn to Violent Reaction (BVR) and Army Burn to Violent
Reaction (ABVR) experiments have been implemented as a sub-scale experiment that
could potentially represent the response of a full scale rocket motor subjected to
fragment impact
1-5
Both nitramine and ammonium perchlorate (AP) based propellants
have been investigated, and multiple parameters, including case material, propellant
thickness, fragment type, fragment velocity, confinement, air gap (spacing between
propellant slabs), and backing material, have been found to affect the outcome. In the
case of nitramine based propellants, significant insight has been gained into the different
detonation mechanisms that could occur inside a rocket motor and what critical
parameters control those responses. For AP based propellants, the BVR/ABVR
experiments have allowed for mapping of the severity of the reaction, based on a variety
of parameters. These findings have been quite useful in understanding the issues and
hazards associated with fragment impact.
Given the understanding, the significant reduction in testing costs, and reduction
in hazards associated with testing that the BVR/ABVR experiment has provided, it would
be very beneficial to validate their accuracy in predicting the actual response of a full
scale motor. Some efforts have been made to accomplish this, but they have been
limited in scope and have focused on AP based propellants. While those efforts showed
promise in validating the BVR/ABVR experiment for AP based propellants, no efforts
have been made to validate them for detonable, nitramine-based, propellants.
As such, the focus of the current effort is to address this lack of subscale model
validation for nitramine-based propellants. To accomplish this, multiple experiments
were conducted using the ABVR setup, and parameters such as fragment velocity,
propellant thickness, and air gap were investigated. These experiments were then
repeated, but cylindrical sections of simulated rocket motors were used. The ABVR
