| On the Swerve Response of Projectiles to Control Input |
APR 2008 |
30 pages |
| Authors:
Douglas Ollerenshaw; Mark Costello; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
|
 | The swerve response of fin- and spin-stabilized projectiles to control mechanism input is sometimes not intuitive and often surprises smart weapon designers. This report seeks to explain the basic parameters that govern swerve of projectiles excited by control input. By modeling the overall effect of any control mechanism as a non-rolling reference frame force or moment applied to the projectile, we obtain general expressions for swerve in terms of basic ... |
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| Model of Predictive Control of a Direct-Fire Projectile Equipped With Canards |
MAR 2005 |
39 pages |
| Authors:
Douglas Ollerenshaw; Mark Costello; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
|
| Launch uncertainties in uncontrolled direct-fire projectiles can lead to significant impact point dispersion, even at relatively short range. A model predictive control scheme for direct-fire projectiles is investigated to reduce impact point dispersion. The control law depends on projectile linear theory to create an approximate linear model of the projectile and quickly predict states into the future. Control inputs are based on minimization of the error between predicted projectile states ... |
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| Linear Theory of a Projectile With a Rotating Internal Part in Atmospheric Flight |
JUL 2003 |
52 pages |
| Authors:
Geoffrey Frost; Mark Costello; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
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| Dynamic modeling of the atmospheric flight mechanics of a projectile equipped with an internal rotating disk is investigated and a modified projectile linear theory is established for this configuration. To model this type of projectile requires alteration of several of the coefficients of the epicyclic dynamics leading to changes in the fast and slow epicyclic modes. A study of the frequency and damping properties of the epicyclic modes is conducted ... |
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| A Comparison of Different Guidance Schemes for a Direct Fire Rocket with a Pulse Jet Control Mechanism |
APR 2002 |
38 pages |
| Authors:
Thanat Jitpraphai; Bradley Burchett; Mark Costello; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
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| Compared to gun launch ammunition, uncontrolled direct fire atmospheric rockets are terribly inaccurate, to the point where they are used most effectively on the battlefield as area weapons. Dispersion characteristics can be dramatically improved by outfitting the rocket with a suitable control mechanism and sensor suite. In the work reported here, a lateral pulse jet control mechanism is considered. The lateral pulse jet mechanism consists of a finite number of ... |
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| Improved Dispersion of a Fin-Stabilized Projectile Using a Passive Moveable Nose |
APR 2001 |
44 pages |
| Authors:
Mark Costello; Raditya Agarwalla; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
|
| A key and often quoted metric associated with gun systems is impact point accuracy. The extent of impact dispersion is a complex function of a battery of parameters, including gun geometry and tolerances, the fire control system, projectile manufacturing tolerances, etc. The work reported here investigates potential impact point accuracy improvement for a penetrator-type projectile realized by replacing the rigid nose cone wind screen with a passive gimballed nose. By ... |
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| Linear Theory of a Dual-Spin Projectile in Atmospheric Flight |
FEB 2000 |
62 pages |
| Authors:
Mark F. Costello; Allen A. Peterson; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
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| The equations of motion for a dual-spin projectile in atmospheric flight are developed and subsequently utilized to solve for angle of attack and swerving dynamics. A combination hydrodynamic and roller bearing couples forward and aft body roll motions. Using a modified projectile linear theory developed for this configuration, it is shown that the dynamic stability factor, S(g), and the gyroscopic stability factor, S(g) are altered compared to ... |
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| Partial Melting and Segregation Behavior in a Superplastic Si3N4/Al-Mg Alloy Composite. |
1995 |
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| Authors:
J. Koike; M. Mabuchi; K. Higashi; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
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 | Al-mg alloy (5052) composite reinforced with si3n4 particulates was investigated by transmission electron microscopy and electron energy loss spectroscopy. partial melting was observed at matrix/reinforcement interfaces and matrix grain boundaries at a temperature near an optimum superplastic temperature. segregation of solute elements (mg and si) was observed at the interfaces and grain boundaries. both partial melting and solute segregation were found to depend on grain boundaries. the obtained results were ... |
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| Restoration Mechanisms in Large-Strain Deformation of High Purity Aluminum at Ambient Temperature |
1994 |
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| Authors:
M. E. Kassner; H. J. McQueen; J. Pollard; E. Evangelista; E. Cerri; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
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| Dynamic restoration on mechanisms associated with 1.5 - 3.0 compression strain deformation of high purity aluminum at room temperature have been studied. stress versus strain behavior, tem, and optical microscopy suggest that the softening due to recrystallization during deformation. |
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| Dynamic Analysis of Cracks in Micropolar Elastic Materials |
93 |
|
| Authors:
T. C. Kennedy; J. B. Kim; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
|
| Finite element analysis was used to analyze the dynamic response of a crack in micropolar elastic materials. This theory is superior to the classical elasticity theory because it can take into account microstructural properties within a continuum framework. Two cases were studied: a stationary crack subjected to a dynamic load, and a constant velocity crack propagation under a constant load. In each case the materials with strong micropolar properties had ... |
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| Mechanical Behavior of Fine Filament Nb-Ti as a Function of Processing |
93 |
|
| Authors:
Z. Guo; W. H. Warnes; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
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| From first heat treatment size to final wire size this paper represents experimental data on the mechanical properties of nb-ti filaments during standard wire processing. fiber geometry, hardness, young's modulus and ultimate strength are fiber characteristics examined in this experiment. the mechanical behavior of fine filament nb-ti was studied under two different processing treatments. in the mechanical modeling of the composite system of cu/ nb-ti, this research is needed. ... |
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| Geometric Dynamic Recrystallization in Aluminium and Aluminium Alloys Above 0.6Tm. |
1993 |
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| Authors:
M. E. Kassner; H. J. McQueen; E. Evangelista; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
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| The relatively new concept of geometric dynamic recrystallization (GRX) is described. It was originally used to explain the observation of the formation of "crystallites" in pure aluminum deformed to relatively large strains at elevated temperature. It has very recently been confirmed to occur in aluminum-magnesium alloys at conditions where classic discontinuous dynamic recrystallization was originally believed to occur. GRX may also occur in a variety of higher stacking fault energy ... |
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| The Effect of Homogenization and Precipitation Treatments on the Extrudability and Ambient- Temperature Mechanical Properties of Aluminum Alloy AA2024. |
1993 |
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| Authors:
M. E. Kassner; X. Li; H. J. McQueen; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
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| This study determined the independent effects of various homogenization cycles and precipitation treatments on the elevated temperature workability and the final ambient temperature mechanical properties for aluminum alloy AA2024. The elevated-temperature tensile and extrusion tests indicate that the workability of AA2024 improves with elevated-temperature precipitation treatments as suggested by earlier investigations. The precipitation treatments do not appear to degrade the ambient-temperature T3 and T8 tensile properties. The time at the ... |
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| The Mechanical Behaviour of U-6Nb Alloy and AISI 1045 and 1215 Steels at High Strain Rates |
92 |
|
| Authors:
R. S. Rosen; M. E. Kassner; K. E. Thiehsen; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
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| Mechanical properties of U-6Nb alloy, AISI 1215, and AISI 1045 steels were determined at conventional and high strain rates; properties included yield stress, ultimate tensile strength, ductility strain-rate sensitivity, and toughness; it was found that AISI 1045 was a comparable substitute for U-6Nb, while AISI 1215 was unacceptable. |
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| Room Temperature Mechanical Properties of Nb-Ti/Cu Superconducting Composites. |
1992 |
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| Authors:
He Liu; William H. Warnes; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
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| This paper concerned mmc in some important way and contained information about, utilized, or discussed these subjects: basic topics:, data, mmc, mmc data materials and material types:, cu matrix, fibers, nb fibers, nb-ti alloys, nbti/cu material characteristics and data fields:, annealing data, elongation data, flow stress data, mechanical properties, strain data, true strain data, uts data, vicker microhardness testing and test conditions:, astm-e-8-87, tensile tests miscellaneous and special technical terms:, ... |
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| The Effect of Grain Size on the Elevated Temperature Yield Strength of Polycrystalline Aluminum |
91 |
|
| Authors:
M. E. Kassner; X. Li; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
|
| Grain-size strengthening in high-purity annealed Al at high temperature was described by the Hall-Petch relation; the Hall-Petch constant varied inversely with temperature, which could be attributed to dynamic recovery processes; the high-temperature strengthening by grain boundaries in annealed polycrystalline Al of a given grain size is less than that of steady-state creep substructures with an identical subgrain size. |
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| Surface and Corrosion Study of Laser-Processed Zirconium Alloys |
91 |
|
| Authors:
J. Rawers; W. Reitz; S. Bullard; E. K. Roub; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
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| Reactor Grade Zirconium (Zircaloy-2) was laser-glazed and laser- alloyed with nickel (Ni) or chromium (Cr) powders; laser alloying produced a surface that was macroscopically, chemically homogeneous; however, at the microscopic level the melt zone was a mixture of microcrystalline pure zirconium (Zr) and extremely fine grain, or possibly amorphous, solid solution regions of Zr and alloying elements; corrosion tests (potentiodynamic and long-term immersion) were conducted in 10% FeCl3 solution; the ... |
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| The Ductility and Microstructure of Aluminum and Aluminum-Magnesium Alloys Deformed to Large Strains at Elevated Temperature |
91 |
|
| Authors:
M. E. Kassner; G. A. Henshall; H. J. McQueen; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
|
| The ductility and microstructure of aluminum and aluminum-magnesium alloys deformed to large strains at elevated temperatures have been studied. Torsional ductility was measured at 110-601 C at strain rates 5.1 x 10-4 - 1.3 x 10-2/s. The ductility, at each strain rate, increases with increasing temperature to a "peak ductility" beyond which it decreases. Al-5.8 at % Mg was deformed to strains up to about 11 at 425 C (epsilon ... |
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| The Effects of Temperature and Strain Rate on Extended Ductility of Aluminum. |
1991 |
|
| Authors:
M. E. Kassner; N. Q. Nguyen; G. A. Henshall; H. J. McQueen; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
|
| The torsional ductility of high purity aluminum was measured over a wide range of temperature and strain rate and several trends were observed; at each strain rate the ductility first increases with increasing temperature to a "peak ductility", beyond which it decreases; dramatic ductilities, of over 90 in some cases, are observed in the vicinity of the peaks; the peak ductility appears to increase with increasing strain rate; contrary to ... |
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| Prediction of Non-Mechanical Transient Strains in Polymer Matrix Composites. |
1991 |
|
| Authors:
Ernest G. Wolff; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
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| A model was developed to predict the transient strains which occur when a carbon fiber reinforced polymer (CFRP) composite is subjected to a new thermal or chemical environment. It is used here to determine the coefficient of in-plane moisture expansion (CME or delta L/L per % moisture content) during transverse (Fickian) diffusion. Moisture induced weight changes follow straight line relationships when plotted against the theoretical fractional weight change G, which ... |
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| (DURIP) Spontaneous Raman System for the Study of Enhanced Combustion and Non-Thermal Plasmas |
26 FEB 90 |
6 pages |
| Authors:
Richard B. Peterson; OREGON STATE UNIV CORVALLIS DEPT OF MECHANICAL ENGINEERING
|
| This report describes the instrumentation purchased on the DURIP grant AFOSR-89-0093 and the research work that this instrumentation will support. The objective of the grant was to acquire elements of a spontaneous Raman system for gas phase diagnostic work on currently funded combustion studies. Toward this end, we have acquired a neodymium: YAG pulsed laser with frequency doubling, an optical multichannel analyzer (OMA), a computer system required to operate the ... |
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