摘要 :
Ballistic testing was conducted on two composite materials: 8HS satin weave S-glass fiber and plain weave Aramid (Kevlar® KM2 600 Denier) fiber, both with a UAF-472 polyurethane thermoplastic matrix. The goals of the ballistic te...
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Ballistic testing was conducted on two composite materials: 8HS satin weave S-glass fiber and plain weave Aramid (Kevlar® KM2 600 Denier) fiber, both with a UAF-472 polyurethane thermoplastic matrix. The goals of the ballistic tests were to determine the effect of matrix material, shot dependency with regard to shot-to-shot distance, degree of penetration from previous shots, and delamination effects of previous shots on the ballistic limit of the material. The measure of performance for each ballistic limit was the projectile velocity with a 50% probability of completely penetrating the armor material, known as V_(50). The ballistic limit was determined by a three-phase optimal design test method, called 3-Pod. The delamination extent was determined by an audiovisual tap test. All plates were 0.25 inches thick and shots were conducted with no obliquity. This investigation was in response to previous research which showed mixed results in the ballistic limit with delamination overlap. The current research found a statistically significant increase in the ballistic limit for Aramid (but mixed results for S-glass) fiber materials in regard to secondary shots. For both materials, there were overall ballistic limit increases when compared to previous research using the same fiber, but with a different matrix.
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摘要 :
Ballistic testing was conducted on two composite materials: 8HS satin weave S-glass fiber and plain weave Aramid (Kevlar® KM2 600 Denier) fiber, both with a UAF-472 polyurethane thermoplastic matrix. The goals of the ballistic te...
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Ballistic testing was conducted on two composite materials: 8HS satin weave S-glass fiber and plain weave Aramid (Kevlar® KM2 600 Denier) fiber, both with a UAF-472 polyurethane thermoplastic matrix. The goals of the ballistic tests were to determine the effect of matrix material, shot dependency with regard to shot-to-shot distance, degree of penetration from previous shots, and delamination effects of previous shots on the ballistic limit of the material. The measure of performance for each ballistic limit was the projectile velocity with a 50% probability of completely penetrating the armor material, known as V_(50). The ballistic limit was determined by a three-phase optimal design test method, called 3-Pod. The delamination extent was determined by an audiovisual tap test. All plates were 0.25 inches thick and shots were conducted with no obliquity. This investigation was in response to previous research which showed mixed results in the ballistic limit with delamination overlap. The current research found a statistically significant increase in the ballistic limit for Aramid (but mixed results for S-glass) fiber materials in regard to secondary shots. For both materials, there were overall ballistic limit increases when compared to previous research using the same fiber, but with a different matrix.
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摘要 :
Ballistic testing was conducted on two composite materials: 8HS satin weave S-glass fiber and plain weave Aramid (Kevlar® KM2 600 Denier) fiber, both with a UAF-472 polyurethane thermoplastic matrix. The goals of the ballistic te...
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Ballistic testing was conducted on two composite materials: 8HS satin weave S-glass fiber and plain weave Aramid (Kevlar® KM2 600 Denier) fiber, both with a UAF-472 polyurethane thermoplastic matrix. The goals of the ballistic tests were to determine the effect of matrix material, shot dependency with regard to shot-to-shot distance, degree of penetration from previous shots, and delamination effects of previous shots on the ballistic limit of the material. The measure of performance for each ballistic limit was the projectile velocity with a 50% probability of completely penetrating the armor material, known as V_(50). The ballistic limit was determined by a three-phase optimal design test method, called 3-Pod. The delamination extent was determined by an audiovisual tap test. All plates were 0.25 inches thick and shots were conducted with no obliquity. This investigation was in response to previous research which showed mixed results in the ballistic limit with delamination overlap. The current research found a statistically significant increase in the ballistic limit for Aramid (but mixed results for S-glass) fiber materials in regard to secondary shots. For both materials, there were overall ballistic limit increases when compared to previous research using the same fiber, but with a different matrix.
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The stability and maneuverability analysis of a small scale subsonic reusable booster concept design was performed through wind tunnel testing, using the USAF Academy subsonic wind tunnel, of a model with various deflections on se...
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The stability and maneuverability analysis of a small scale subsonic reusable booster concept design was performed through wind tunnel testing, using the USAF Academy subsonic wind tunnel, of a model with various deflections on several control surfaces. Control surfaces included flaps, canards, rudders, and a combined elevon/aileron. Testing conducted at Mach 0.15 and Mach 0.3 simulated landing, while Mach 0.5 modeled the first seconds of take-off. Data acquired provided values for analysis of the pitch, yaw, and roll stability coefficients as well as several performance factors for the reusable booster concept. The results showed that for most configurations and Mach numbers, the model stalled past +10 to +12 degrees angle of attack (AoA). The model had strong roll stability, but poor yaw stability for most configurations. The model exhibited an average L/D ratio of 6 to 8. In general, the trim AoA for stability were low, suggesting the need to adjust the center of gravity of the model to trim at a higher AoA. As AoA increased for landing configurations, the model became unstable in yaw, suggesting the need for larger vertical surfaces. The canard effect of flow over the wing was examined. The canard was rotated azimuth ally about the center axis of the model at 0, 15, and 30 degrees. This data showed that the zero degree canard location experience wake interference with the wing. The 30 degree rotation caused unfavorable yaw stability, suggesting a 15 degree optimal rotation. The data reduced from this experimentation was tested for reliability through an uncertainty analysis.
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摘要 :
The stability and maneuverability analysis of a small scale subsonic reusable booster concept design was performed through wind tunnel testing, using the USAF Academy subsonic wind tunnel, of a model with various deflections on se...
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The stability and maneuverability analysis of a small scale subsonic reusable booster concept design was performed through wind tunnel testing, using the USAF Academy subsonic wind tunnel, of a model with various deflections on several control surfaces. Control surfaces included flaps, canards, rudders, and a combined elevon/aileron. Testing conducted at Mach 0.15 and Mach 0.3 simulated landing, while Mach 0.5 modeled the first seconds of take-off. Data acquired provided values for analysis of the pitch, yaw, and roll stability coefficients as well as several performance factors for the reusable booster concept. The results showed that for most configurations and Mach numbers, the model stalled past +10 to +12 degrees angle of attack (AoA). The model had strong roll stability, but poor yaw stability for most configurations. The model exhibited an average L/D ratio of 6 to 8. In general, the trim AoA for stability were low, suggesting the need to adjust the center of gravity of the model to trim at a higher AoA. As AoA increased for landing configurations, the model became unstable in yaw, suggesting the need for larger vertical surfaces. The canard effect of flow over the wing was examined. The canard was rotated azimuth ally about the center axis of the model at 0, 15, and 30 degrees. This data showed that the zero degree canard location experience wake interference with the wing. The 30 degree rotation caused unfavorable yaw stability, suggesting a 15 degree optimal rotation. The data reduced from this experimentation was tested for reliability through an uncertainty analysis.
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A six degree-of-freedom (6DOF) analysis of various conventional satellite bus configurations, and aeroelastic effects on the deployed solar panels during atmospheric reentry is presented. Accounting for demisability is an integral...
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A six degree-of-freedom (6DOF) analysis of various conventional satellite bus configurations, and aeroelastic effects on the deployed solar panels during atmospheric reentry is presented. Accounting for demisability is an integral step of designing and manufacturing satellites and with disposable equipment on board, the emphasis on structural strength and robust thermal protection system (TPS) pales for a conventional satellite in comparison to reentry capsules, which are specifically designed to withstand the intense aerothermodynamic effects experienced during reentry. However, if the satellite contained sensitive or critical systems/payloads on board, it may be essential to ascertain and quantify these environmental effects in order to ensure the spacecraft's survivability. This research examines the terminal reentry characteristics of common satellite bus geometry and solar panel array, including aerodynamic and thermal loading, and the deceleration imparted on the satellite body. This includes an analysis of structural dynamics as the solar panel array experiences loading due to these environmental effects, with focus on characterizing bending stress, vibrational mode shapes, and flutter if applicable.
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A liquid bipropellant rotating detonation rocket engine was successfully fired at Purdue University. The 6.5 inch diameter engine and operates on a mixture of rocket grade hydrogen peroxide and triglyme. Ignition is accomplished h...
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A liquid bipropellant rotating detonation rocket engine was successfully fired at Purdue University. The 6.5 inch diameter engine and operates on a mixture of rocket grade hydrogen peroxide and triglyme. Ignition is accomplished hypergolically, with the addition of a promoter to the fuel. Eight cases of spontaneously initiated, single wave, rotating detonations were observed. Detonation wave speeds were near or exceeding Chapman Jouget calculations. Evidence of condensed phase reactions was also seen, damaging hardware in short order. Both a rotating detonation and a bulk-slapping mode characterized the engine operation.
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A liquid bipropellant rotating detonation rocket engine was successfully fired at Purdue University. The 6.5 inch diameter engine and operates on a mixture of rocket grade hydrogen peroxide and triglyme. Ignition is accomplished h...
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A liquid bipropellant rotating detonation rocket engine was successfully fired at Purdue University. The 6.5 inch diameter engine and operates on a mixture of rocket grade hydrogen peroxide and triglyme. Ignition is accomplished hypergolically, with the addition of a promoter to the fuel. Eight cases of spontaneously initiated, single wave, rotating detonations were observed. Detonation wave speeds were near or exceeding Chapman Jouget calculations. Evidence of condensed phase reactions was also seen, damaging hardware in short order. Both a rotating detonation and a bulk-slapping mode characterized the engine operation.
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Reliability analysis using satellite failure data for satellites launched in the years 1991-2020 is presented. The analysis is conducted using nonparametric as well as parametric methods. In order to derive a nonparametric reliabi...
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Reliability analysis using satellite failure data for satellites launched in the years 1991-2020 is presented. The analysis is conducted using nonparametric as well as parametric methods. In order to derive a nonparametric reliability estimate from the raw failure data, the Kaplan-Meier estimator is utilized. The Weibull distribution is then utilized to attempt and parameterize the behaviors seen in the nonparametric results. To better interpret the data, data is split into groups with respect to launch dates. Results from this analysis show a general increase in overall satellite reliability over the previous 30 years.
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The concept of spacecraft fractionation has provided an enhanced potential for mission utility, cost, and performance with respect to traditional, monolithic spacecraft architectures. By dividing a spacecraft into separate functio...
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The concept of spacecraft fractionation has provided an enhanced potential for mission utility, cost, and performance with respect to traditional, monolithic spacecraft architectures. By dividing a spacecraft into separate functional modules within a close-proximity formation, fractionation permits the incremental replacement of individual modules rather than the entire space system. However, a formation of fractionated spacecraft modules still features many of the same risks as traditional, such as the possibility of an onboard catastrophic mishap. This research looks at the mission survivability of a fractionated formation in a variety of orbital regimes assuming a battery explosion aboard one of the constituent spacecraft modules. Specifically, the probability of debris impact arising from the explosion will be determined for the formation based on relative formation distance, formation configuration, and orbital altitude. Also, the magnitude of the explosion and the resultant fragmentation debris will seed vulnerability analysis to determine the likelihood of survivability for the remaining fractionated spacecraft.
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