Optimal redesign study of the harm wing

The purpose of this project was to investigate the use of optimization techniques to improve the flutter margins of the HARM AGM-88A wing. The missile has four cruciform wings, located near mid-fuselage, that are actuated in pairs symmetrically and antisymmetrically to provide pitch, yaw, and roll control. The wings have a solid stainless steel forward section and a stainless steel crushed-honeycomb aft section. The wing restraint stiffness is dependent upon wing pitch amplitude and varies from a low value near neutral pitch attitude to a much higher value at off-neutral pitch attitudes, where aerodynamic loads lock out any free play in the control system. The most critical condition for flutter is the low-stiffness condition in which the wings are moved symmetrically. Although a tendency toward limit-cycle flutter is controlled in the current design by controller logic, wing redesign to improve this situation is attractive because it can be accomplished as a retrofit. In view of the exploratory nature of the study, it was decided to apply the optimization to a wing-only model, validated by comparison with results obtained by Texas Instruments (TI). Any wing designs that looked promising were to be evaluated at TI with more complicated models, including body modes. The optimization work was performed by McIntosh Structural Dynamics, Inc. (MSD) under a contract from TI

Static aeroelastic analysis and tailoring of missile control fins

A concept for enhancing the design of control fins for supersonic tactical missiles is described. The concept makes use of aeroelastic tailoring to create fin designs (for given planforms) that limit the variations in hinge moments that can occur during maneuvers involving high load factors and high angles of attack. It combines supersonic nonlinear aerodynamic load calculations with finite-element structural modeling, static and dynamic structural analysis, and optimization. The problem definition is illustrated. The fin is at least partly made up of a composite material. The layup is fixed, and the orientations of the material principal axes are allowed to vary; these are the design variables. The objective is the magnitude of the difference between the chordwise location of the center of pressure and its desired location, calculated for a given flight condition. Three types of constraints can be imposed: upper bounds on static displacements for a given set of load conditions, lower bounds on specified natural frequencies, and upper bounds on the critical flutter damping parameter at a given set of flight speeds and altitudes. The idea is to seek designs that reduce variations in hinge moments that would otherwise occur. The block diagram describes the operation of the computer program that accomplishes these tasks. There is an option for a single analysis in addition to the optimization

RATIONAL EXPECTATIONS ESTIMATION OF GEORGIA SOYBEAN ACREAGE RESPONSE

The general method of moments procedure is used for estimating a soybean acreage response function assuming the producers hold rational expectations. Results indicate that soybean, corn, and wheat futures prices, lagged acreage, and government programs are significant factors for determining soybean plantings. Implications of the results are that crop acreage selection by Georgia producers is not very responsive to demand shocks. Thus, producers in other regions are more likely to absorb impacts from these shocks on crop acreage selection.Soybeans, GMM, Elasticities, Crop Production/Industries,

Real Property

Many cases were decided in the field of real property during the period covered by the survey, but very few of them were decided in the California Supreme Court. There is one case of special importance that was decided in the Appellate Department of the Superior Court. Only those cases thought to be of special significance are included in this survey, and legislation enacted during the period will not be discussed

The Relationship of Winning a Pulitzer Prize to Newspaper Circulation

The purpose of this study was to determine if there is a relationship between newspaper quality and newspaper success. Winning a Pulitzer Prize was the operational definition of quality, while success was operationalized as increased circulation. Twenty-two newspapers, all morning or all-day dailies, were studied in this project. Eleven of the papers which won Pulitzer Prizes in the period of 1979 to 1989 were compared to 11 similar newspapers which did not win Pulitzers. The winning papers over the 11-year period outdistanced the non-winning papers in circulation population ratio by 1.58 percent per year. A relationship was found in a variety of ways, including using a ratio of population increases to circulation increases and comparing average ratios over an 11-year period to ratios in the years when Pulitzer material appeared in the newspaper and in the years when the announcement of the award was made. Data show that the ratio was highest in announcement years, indicating there is a relationship between winning and Pulitzer Prize and increased circulation

Real Property

Many cases were decided in the field of real property during the period covered by the survey, but very few of them were decided in the California Supreme Court. There is one case of special importance that was decided in the Appellate Department of the Superior Court. Only those cases thought to be of special significance are included in this survey, and legislation enacted during the period will not be discussed