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In this paper, the squeezing effect, the bunching effect and the anti-bunching effect of the superposition light field state which involving q-deformation vacuum state and q-Glauber coherent state are studied, the controllable q-parameter of the squeezing effect, the bunching effect and the anti-bunching effect of q-deformed superposition light field state are obtained.
During the past decade, computational simulation of fluid flow around complex configurations has progressed significantly and many notable successes have been reported, however, unsteady time-dependent solutions are not easily obtainable. The present effort involves unsteady time dependent simulation of temporally deforming geometries. Grid generation for a complex configuration can be a time consuming process and temporally varying geometries necessitate the regeneration of such grids for every time step. Traditional grid generation techniques have been tried and demonstrated to be inadequate to such simulations. Non-Uniform Rational B-splines (NURBS) based techniques provide a compact and accurate representation of the geometry. This definition can be coupled with a distribution mesh for a user defined spacing. The present method greatly reduces cpu requirements for time dependent remeshing, facilitating the simulation of more complex unsteady problems. A thrust vectoring nozzle has been chosen to demonstrate the capability as it is of current interest in the aerospace industry for better maneuverability of fighter aircraft in close combat and in post stall regimes. This current effort is the first step towards multidisciplinary design optimization which involves coupling the aerodynamic heat transfer and structural analysis techniques. Applications include simulation of temporally deforming bodies and aeroelastic problems.
The cyclic, high-temperature deformation behavior of a wrought cobalt-base super-alloy, Haynes 188, is investigated under combined axial and torsional loads. This is accomplished through the examination of hysteresis loops generated from a biaxial fatigue test program. A high-temperature axial, torsional, and combined axial-torsional fatigue database has been generated on Haynes 188 at 760 C. Cyclic loading tests have been conducted on uniform gage section tubular specimens in a servohydraulic axial-torsional test rig. Test control and data acquisition were accomplished with a minicomputer. The fatigue behavior of Haynes 188 at 760 C under axial, torsional, and combined axial-torsional loads and the monotonic and cyclic deformation behaviors under axial and torsional loads have been previously reported. In this paper, the cyclic hardening characteristics and typical hysteresis loops in the axial stress versus axial strain, shear stress ,versus engineering shear strain, axial strain versus engineering shear strain. and axial stress versus shear stress spaces are presented for cyclic in-phase and out-of-phase axial-torsional tests. For in-phase tests, three different values of the proportionality constant lambda (the ratio of engineering shear strain amplitude to axial strain amplitude, are examined, viz. 0.86, 1.73, and 3.46. In the out-of-phase tests, three different values of the phase angle, phi (between the axial and engineering shear strain waveforms), are studied, viz., 30, 60, and 90 degrees with lambda equals 1.73. The cyclic hardening behaviors of all the tests conducted on Haynes 188 at 760 C are evaluated using the von Mises equivalent stress-strain and the maximum shear stress-maximum engineering shear strain (Tresca) curves. Comparisons are also made between the hardening behaviors of cyclic axial, torsional, and combined in-phase (lambda = 1.73 and phi = 0) and out-of-phase (lambda = 1.73 and phi = 90') axial-torsional fatigue tests. These comparisons are accomplished through simple Ramberg-Osgood type stress-strain functions for cyclic, axial stress-strain and shear stress-engineering shear strain curves.
The first International Symposium on Strain Gauge Balances was sponsored under the auspices of the NASA Langley Research Center (LaRC), Hampton, Virginia. Held at the LaRC Reid Conference Center, the Symposium provided an open international forum for presentation, discussion, and exchange of technical information among wind tunnel test technique specialists and strain gauge balance designers. The Symposium also served to initiate organized professional activities among the participating and relevant international technical communities. The program included a panel discussion, technical paper sessions, tours of local facilities, and vendor exhibits. Over 130 delegates were in attendance from 15 countries. A steering committee was formed to plan a second international balance symposium tentatively scheduled to be hosted in the United Kingdom in 1998 or 1999. The Balance Symposium was followed bv the half-day, Workshop on Angle of Attack and Model Deformation on the afternoon of October 25. The thrust of the Workshop was to assess the state of the art in angle of attack (AoA) and model deformation measurement techniques and to discuss future developments.
The damping capacity of several aluminum-copper alloys has been investigated during tensile elongation. This damping is shown to depend on strain rate, strain, temperature, alloy content, and heat treatment. A tentative hypothesis, based on the acceleration of solute atom diffusion by deformation-produced vacancies, is proposed to account for the observed behavior. Internal-friction maxima are observed in deformed aluminum and aluminum-copper alloys at -70 deg and -50 deg C. The peaks appear to be relatively insensitive to frequency and alloy content, but they disappear after annealing at temperatures nearing the recrystallization temperature.
An analysis is made of wing deflection and streamwise twist measurements in rough-air flight of a large flexible swept-wing bomber. Random-process techniques are employed in analyzing the data in order to describe the magnitude and characteristics of the wing deflection and twist responses to rough air. Power spectra and frequency-response functions for the wing deflection and twist responses at several spanwise stations are presented. The frequency-response functions describe direct and absolute response characteristics to turbulence and provide a convenient basis for assessing analytic calculation techniques. The wing deformations in rough air are compared with the expected deformations for quasi-static loadings of the same magnitude, and the amplifications are determined. The results obtained indicate that generally the deflections are amplified by a small amount, while the streamwise twists are amplified by factors of the order of 2.0. The magnitudes of both the deflection velocities and the twist angles are shown to have significant effects on the local angles of attack at the various stations and provide the main source of aerodynamic loading, particularly at frequencies in the vicinity of the first wing-vibration mode.
A research program is being undertaken to develop rate dependent deformation and failure models for the analysis of polymer matrix composite materials. In previous work in this program, strain-rate dependent inelastic constitutive equations used to analyze polymers have been implemented into a mechanics of materials based composite micromechanics method. In the current work, modifications to the micromechanics model have been implemented to improve the calculation of the effective inelastic strain. Additionally, modifications to the polymer constitutive model are discussed in which pressure dependence is incorporated into the equations in order to improve the calculation of constituent and composite shear stresses. The Hashin failure criterion is implemented into the analysis method to allow for the calculation of ply level failure stresses. The deformation response and failure stresses for two representative uniaxial polymer matrix composites, IM7/977-2 and AS4-PEEK, are predicted for varying strain rates and fiber orientations. The predicted results compare favorably to experimentally obtained values.
The first International Symposium on Strain Gauge Balances was sponsored under the auspices of the NASA Langley Research Center (LaRC), Hampton, Virginia during October 22-25, 1996. Held at the LaRC Reid Conference Center, the Symposium provided an open international forum for presentation, discussion, and exchange of technical information among wind tunnel test technique specialists and strain gauge balance designers. The Symposium also served to initiate organized professional activities among the participating and relevant international technical communities. The program included a panel discussion, technical paper sessions, tours of local facilities, and vendor exhibits. Over 130 delegates were in attendance from 15 countries. A steering committee was formed to plan a second international balance symposium tentatively scheduled to be hosted in the United Kingdom in 1998 or 1999. The Balance Symposium was followed by the half-day Workshop on Angle of Attack and Model Deformation on the afternoon of October 25. The thrust of the Workshop was to assess the state of the art in angle of attack (AoA) and model deformation measurement techniques and to discuss future developments.
The purpose of this project was to carry out GPS observations on the Kenai Peninsula, southern Alaska, in order to study the postseismic and contemporary deformation following the 1964 Alaska earthquake. All of the research supported in this grant was carried out in collaboration with Dr. Steven Cohen of Goddard Space Flight Center. The research funding from this grant primarily supported GPS fieldwork, along with the acquisition of computer equipment to allow analysis and modeling of the GPS data. A minor amount of salary support was provided by the PI, but the great majority of the salary support was provided by the Geophysical Institute. After the expiration of this grant, additional funding was obtained from the National Science Foundation to continue the work. This grant supported GPS field campaigns in August 1995, June 1996, May-June and September 1997, and May-June 1998. We initially began the work by surveying leveling benchmarks on the Kenai peninsula that had been surveyed after the 1964 earthquake. Changes in height from the 1964 leveling data to the 1995+ GPS data, corrected for the geoid-ellipsoid separation, give the total elevation change since the earthquake. Beginning in 1995, we also identified or established sites that were suitable for long-term surveying using GPS. In the subsequent annual GPS campaigns, we made regular measurements at these GPS marks, and steadily enhanced our set of points for which cumulative postseismic uplift data were available. From 4 years of Global Positioning System (GPS) measurements, we find significant spatial variations in present-day deformation between the eastern and western Kenai peninsula, Alaska. Sites in the eastern Kenai peninsula and Prince William Sound move to the NNW relative to North America, in the direction of Pacific-North America relative plate motion. Velocities decrease in magnitude from nearly the full plate rate in southern Prince William Sound to about 30 mm/yr at Seward and to about 5 mm/yr near Anchorage. In contrast, sites in the western Kenai peninsula move to the SW, in a nearly trenchward direction, with a velocity of about 20 mm/yr. The data are consistent with the shallow plate interface offshore and beneath the eastern Kenai and Prince William Sound being completely locked or nearly so, with elastic strain accumulation resulting in rapid motion in the direction of relative plate motion of sites in the overriding plate. The velocities of sites in the western Kenai, along strike to the southwest, are opposite in sign with those predicted from elastic strain accumulation. These data are incompatible with a significant locked region in this segment of the plate boundary. Trenchward velocities are found also for some sites in the Anchorage area. We interpret the trenchward velocities as being caused by a continuing postseismic transient from the 1964 great Alaska earthquake.
Pressure-sensitive paint (PSP) and video model deformation (VMD) systems have been installed in the Unitary Plan Wind Tunnel at the NASA Langley Research Center to support the supersonic wind tunnel testing requirements of the High Speed Research (HSR) program. The PSP and VMD systems have been operational since early 1996 and provide the capabilities of measuring global surface static pressures and wing local twist angles and deflections (bending). These techniques have been successfully applied to several HSR wind tunnel models for wide ranges of the Mach number, Reynolds number, and angle of attack. A review of the UPWT PSP and VMD systems is provided, and representative results obtained on selected HSR models are shown. A promising technique to streamline the wind tunnel testing process, Modern Experimental Design, is also discussed in conjunction with recently-completed wing deformation measurements at UPWT.
Pressure-sensitive paint (PSP) and video model deformation (VMD) systems have been installed in the Unitary Plan Wind Tunnel at the NASA Langley Research Center to support the supersonic wind tunnel testing requirements of the High Speed Research (HSR) program. The PSP and VMD systems have been operational since early 1996 and provide the capabilities of measuring global surface static pressures and wing local twist angles and deflections (bending). These techniques have been successfully applied to several HSR wind tunnel models for wide ranges of the Mach number, Reynolds number, and angle of attack. A review of the UPWT PSP and VMD systems is provided, and representative results obtained on selected HSR models are shown. A promising technique to streamline the wind tunnel testing process, Modern Experimental Design, is also discussed in conjunction with recently-completed wing deformation measurements at UPWT.
This paper describes a videogram metric technique for determining aerodynamic loads based on optical elastic deformation measurements. The data reduction methods are developed to extract the normal force and pitching moment from beam deformation data. The axial force is obtained by measuring the axial translational motion of a movable shaft in a spring/bearing device. Proof-of-concept calibration experiments are conducted to assess the accuracy of this optical technique.
This paper describes a videogrammetric technique for determining aerodynamic loads based on optical elastic deformation measurements. The data reduction methods are developed to extract the normal force and pitching moment from beam deformation data. The axial force is obtained by measuring the axial translational motion of a movable shaft in a spring/bearing device. Proof-of-concept calibration experiments are conducted to assess the accuracy of this optical technique.
The objective of the proposed research is to experimentally study the effect of strain rate on mechanical response (deformation and failure) of IM-7/977-2 carbon fiber/epoxy matrix composites. The experimental data will provide the information needed for the development of a nonlinear, rate dependent deformation and strength model for this material that can subsequently be used in design.
A {1,2}-order theory for laminated composite and sandwich plates is extended to include thermoelastic effects. The theory incorporates all three-dimensional strains and stresses. Mixed-field assumptions are introduced which include linear in-plane displacements, parabolic transverse displacement and shear strains, and a cubic distribution of the transverse normal stress. Least squares strain compatibility conditions and exact traction boundary conditions are enforced to yield higher polynomial degree distributions for the transverse shear strains and transverse normal stress through the plate thickness. The principle of virtual work is used to derive a 10th-order system of equilibrium equations and associated Poisson boundary conditions. The predictive capability of the theory is demonstrated using a closed-form analytic solution for a simply-supported rectangular plate subjected to a linearly varying temperature field across the thickness. Several thin and moderately thick laminated composite and sandwich plates are analyzed. Numerical comparisons are made with corresponding solutions of the first-order shear deformation theory and three-dimensional elasticity theory. These results, which closely approximate the three-dimensional elasticity solutions, demonstrate that through - the - thickness deformations even in relatively thin and, especially in thick. composite and sandwich laminates can be significant under severe thermal gradients. The {1,2}-order kinematic assumptions insure an overall accurate theory that is in general superior and, in some cases, equivalent to the first-order theory.
Deformation (constitutive relations) of free-standing, thick thermal barrier coatings of sprayed ZrO2-8Wt% Y2O3 was determined at ambient temperature in both pure tension and pure compression using cylindrical bar test specimens. The material exhibited both significant nonlinearity and hysteresis in its load-strain curves, The load-strain relations in four-point uniaxial flexure were determined from tension and compression sides and were compared with individual pure tension and compression constitutive data. Effect of sintering on deformation behavior was significant, resulting in a dramatic change in constitutive relation. Cyclic fatigue testing of the coating material in tension-tension at room temperature showed an insignificant susceptibility to fatigue, similar to the slow crack growth behavior of the material in flexure in 800 C air.
In reduced deformation experiments on an ordinary H6 chondrite, we observe niningerite and oldhamite, which are found only in enstatite chondrites. The association of the reduced metal in shear zones suggests that deformation can enhance reaction. Additional information is contained in the original extended abstract.
To investigate the role of deformation on the distribution of core-forming melt in a partially molten peridotite, samples of olivine-basalt-iron sulfide were sheared to large strains. Dramatic redistribution of sulfide and silicate melts occur during deformation. Additional information is contained in the original extended abstract.