Influence of storage environment upon crack opening and growth in composite solid rocket propellant

Defects formed in solid rocket propellant during manufacturing, transportation, storage, and assembly can lead to alterations in the thrust time profiles and possibly catastrophic failure of the entire rocket. In order to determine the effects of temperature, loading rate, and thickness on this particulate composite, tests were conducted at three temperatures and two loading rates. Both uncracked and edge cracked "biaxial" specimens were produced from solid rocket propellant. The stress relaxation modulus and stress-strain data were obtained from load curves formed during "biaxial" tension tests. Near crack tip displacements and strains were calculated from photographs taken of a surface grating on the pre-cracked specimens during crack propagation. The effect of thickness, temperature, and loading rate on the stress intensity factor was also studied. Finally, by applying continuum theory the displacement singularity was determined at different stages of crack growth. From the stress strain data, it was found that temperature had a greater influence on behavior than loading rate over the ranges studied. The crack growth in the composite material consists of a series of crack opening, crack blunting, and crack growth/resharpening stages which are highly nonlinear. However, the thick specimen at low temperature did not follow this crack growth mechanism. At -65°F the thick specimen developed transverse constraints which caused a brittle fracture to occur when the specimen was loaded. Determination of the displacement singularity order for the sharp cracks was found to be consistent with the theoretical results predicted by Benthem.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Engineering Mechanics

Department dc:contributor.department

Engineering Mechanics

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1993

Author dc:creator

• Tanaka, Martin Lyn

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-01242009-063016

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/40723