Comparison of Hand and Mechanically Mixed AP/HTPB Solid Composite Propellants

Stephens, Matthew; Sammet, Thomas; LePage, Alexander; Carro, Rodolphe; Moslehy, Kareem; Petersen, Eric L.

doi:10.2514/6.2007-5765

Cited by 30 publications

(7 citation statements)

References 3 publications

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“…Hand-mixing techniques provide qualitative insight on viscosity and extrusion [15]. Due to potential exposure and ignition dangers, mixing occurs under a Labonoco fume hood, and personnel use protective clothing while standing on a floor coated with Electrostatic Discharge paint.…”

Section: Methodsmentioning

confidence: 99%

Aging Effects of Composite AP/HTPB Propellants Containing Nano-Sized Additives

Sammet¹,

Demko²,

Dillier³

et al. 2015

51st AIAA/SAE/ASEE Joint Propulsion Conference

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The aging behavior of a composite propellant is a key indicator in the service life of a practical rocket motor. Advancements in the development of nano-particle additives and their burning rate enhancing characteristics give rise to examining the long-term impacts on the service life of the motor. Recent research at Texas A&M has focused on tailoring ballistic characteristics through the addition of nano-additives specifically synthesized for composite propellants. This paper focuses on an AP/HTPB propellant with a dry-powder nano-titania additive to influence ballistic characteristics and fluorescing Lumidots to assess morphological changes associated with accelerated aging. Sample sets were aged at 85 o C in ambient humidity conditions for six and twelve days, simulating four and eight years of aging, respectively. Data were correlated to a set of naturally aged samples. Acceleratedaged monomodal AP formulations with 80% solids loading and nano-additive demonstrated an approximate 7% decrease in burning rate, with accompanying morophological changes. Accelerated-aged bimodal AP forumlations with 85% solids loading and nano-additive demonstrated an approximate 12% increase in burning rates, with accompanying morphological changes. Nomenclature a = burning rate constant (also called temperature coefficient) n = pressure coefficient in burning rate relation P = pressure r = burning rate

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Section: Methodsmentioning

confidence: 99%

Aging Effects of Composite AP/HTPB Propellants Containing Nano-Sized Additives

Sammet¹,

Demko²,

Dillier³

et al. 2015

51st AIAA/SAE/ASEE Joint Propulsion Conference

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“…The continuous involvement of the teacher participant over several years has led to his direct and significant contributions toward several conference and journal papers. 6,[12][13][14][15][16] …”

Section: Research Experiences For Teachers Portionmentioning

confidence: 99%

Texas Center for Undergraduate Research in Energy and Propulsion: An NSF REU Site at Texas A&M University

Eric¹,

Thomas²,

Ranjan³

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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Since 2010, a Research Experiences for Undergraduates (REU) site focusing on energy-, propulsion-, and combustion-related research topics has been held at Texas A&M University (TAMU). A major focus of the site has been the recruitment of undergraduate participants from schools within the state of Texas that do not have major research programs in engineering. To this end, 85% of the 10-week, summer participants have fallen within this category. Four main summer sites have been held to date, involving 40 total participants. Of these students, at least 63% of them were also from underrepresented groups within the STEM fields (female, Hispanic, Black, and Native Americans). Other aspects of the REU site include the participation of one high school teacher each year and a year-round research program that involves 2 students from TAMU as well as 2 students from one of two different partner universities representing non-Tier-One research institutions in Texas, namely the University of North Texas and the University of Texas at Brownsville. Highlights on the overall program, a summary of the research projects and mentors, and details from the last four years of the REU site are provided in this paper.

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“…Over the pasts everal years, the authors have refined laboratory-scale propellant mixing procedures to improve propellant uniformity and mimicry of real-world propellants. Each propellant presented in this paper was manufactured according to these methods, which have been validated to produce consistent results thata re nearly identical to mechanical mixing byS tephens et al [56].T he general procedure that has been developed has been seen to maximize uniformity of the propellant matrixa nd repeatability in burning rate and mechanical property data.…”

Section: Propellant Mixing Proceduresmentioning

confidence: 99%

Mechanical Properties of Composite AP/HTPB Propellants Containing Novel Titania Nanoparticles

Thomas

Demko

Sammet

et al. 2016

Propellants Explo Pyrotec

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Modern chemical synthesis techniques have allowed for improved incorporation of nano‐scale additives into solid propellants. Various methods were implemented to incorporate titania nanoparticles into three representative ammonium perchlorate composite propellants (APCP), and the mechanical properties of each formulation were tested and compared to those of an analogous baseline. Advanced imaging techniques were applied to all particle synthesis methods to characterize particle size and particle network type and size. Uniaxial tensile testing was performed to measure propellant ultimate strength, ductility, and elastic modulus. In general, the addition of nano‐titania additives to the propellant decreased propellant strength and modulus, but improved ductility. Propellant formulations containing in‐situ titania exhibited an increase in ductility of 11 %, 286 %, and 186 % with a corresponding reduction in strength of 82 %, 52 %, and 17 % over analogous baselines. These trends corresponded to a simultaneous decrease in propellant density, indicating that when implementing nano‐sized additives, care must be taken to monitor the effect of the altered manufacturing techniques on propellant physical properties in addition to just monitoring burning rates. Tailoring of propellant manufacturing procedures and the addition of Tepanol bonding agent to an in‐situ APCP formulation fully recovered the propellant density and ultimate strength while retaining the enhanced ductility.

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Comparison of Hand and Mechanically Mixed AP/HTPB Solid Composite Propellants

Cited by 30 publications

References 3 publications

Aging Effects of Composite AP/HTPB Propellants Containing Nano-Sized Additives

Aging Effects of Composite AP/HTPB Propellants Containing Nano-Sized Additives

Texas Center for Undergraduate Research in Energy and Propulsion: An NSF REU Site at Texas A&M University

Mechanical Properties of Composite AP/HTPB Propellants Containing Novel Titania Nanoparticles

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