NORTH AMERICAN ROCKWELL CORP LOS ANGELES CALIF LOS ANGELES DIV

Boron-Epoxy Wing Skins F-100D Aircraft Structural Design and Analysis( Book )
3 editions published in 1971 in English and held by 1 library worldwide
This document constitutes the final report on the structural analysis and design of boron-epoxy wing skins. The design and fabrication of boron composite laminate skins are intended to replace the upper and lower structural covers of the F-100D wing. This report presents the final design of these boron-epoxy wing skins and the material properties and structural analysis. Structural optimization and analysis are presented. (P.S.-PL).

The Early Detection of Fatigue Damage( Book )
2 editions published between 1970 and 1971 in English and held by 1 library worldwide
The report describes the continuing effort to develop nondestructive test methods capable of determining the extent of fatigue damage and providing a means of predicting the future safe life of aerospace materials and structures. During the report period, the fatigue process in 1100-O aluminum was studied by means of exoelectron emission and acoustic emission measurements. The exoelectron observations were by means of measuring the current produced by fatigue damage in air; the acoustic emission measurement was based on the number of acoustic events occurring in selected time intervals during fatigue. It appears that there is a trend indicative of a stress-independent relationship between the change of exoelectron emission current and the percentage of the spent fatigue life based on the current after a selected number of cycles. The intensity of acoustic emission was shown to increase or decrease by orders of magnitude during the fatigue life. The first significant change of acoustic emission was apparently correlatable to 8 to 20 percent of the specimen fatigue life. The continuing metallographic examination confirmed that surface slip striations appear very early in the fatigue process and appear to directly correlate with the exoelectron emission phenomenon. (Author).

Effects of Thermomechanical Treatments on Aluminum Alloys( Book )
1 edition published in 1972 in English and held by 1 library worldwide
The effects produced by thermomechanical treatments on the mechanical, microstructural, and stress corrosion resistance properties of 2024, 7049, and 7075 aluminum alloys were investigated. These properties are compared with those obtained in the standard commercial tempers. The optimum benefits of thermomechanical processing are obtained when the material has previously been heattreated to its maximum age-hardenable condition. A thermomechanical response is developed with as little as 5 percent mechanical deformation. The uniformity of this plastic strain throughout the entire mass of the material is a critical factor. This mechanical deformation is carried out at a temperature high enough to develop a homogeneous random distribution of dislocations and to stabilize this configuration by precipitation along a portion of their lengths. The optimum temperature for a postdeformation heat treatment to produce the necessary resistance to stress corrosion cracking is just above the Guinier-Preston zone solvus for the hardening phase. (Author).

Propulsion System Flow Stability Program (Dynamic). Part XX. Computer Programs for the Root Locus Analysis of Linearized Turbojet and Turbofan Control Systems( Book )
1 edition published in 1968 in English and held by 1 library worldwide
Computer programs developed to handle the computational tasks for the linear stability analysis of propulsion controls by root locus techniques are described. The descriptions, flowcharts, and Fortran program listings of two main programs TJET and TFAN developed for the analysis of turbojet and turbofan engine control systems are presented. Also presented are the descriptions of three subroutines specially developed to facilitate data handling for this study. Examples are given to illustrate the application of computer programs TJET and TFAN. (Author).

Life Support Systems Requirements. Volume III. Section III. Environment Description( Book )
1 edition published in 1970 in English and held by 1 library worldwide
The volume identifies pertinent characteristics of the operational environment, the natural world-wide environment and the induced environment. Data are presented in a manner to clearly define areas having life support systems design implications. (Author).

Relaxation Processes in Metastable Beta Titanium Alloys( Book )
1 edition published in 1971 in English and held by 1 library worldwide
Extensive observations have been made on an internal friction peak in a series of metastable beta Ti-Mo and -V alloys. The peak was observed at two frequencies (10 to the 4th c/s and 10 to the 7th c/s) in temperature ranges of 120K to 140K and 153K to 210+K respectively depending on alloy compositions as well as frequency. In both alloy systems, the peak strength passed through a maximum with increasing alloy content at or near the upper compositional bound for athermal omega formation. In both alloy systems, the peak persisted at compositions well above the upper compositional bound for athermal omega formation although it was greatly diminished in height. The peak's strength was severely reduced by annealing in the thermal omega precipitation temperature range. The results of the work will be compared to the properties of a similar internal friction peak reported earlier in Zr base alloys. (Author).

Mechanical Behavior of High-Strength Beta-Titanium Alloys( Book )
1 edition published in 1971 in English and held by 1 library worldwide
Thermomechanical treatments of Beta-III (11.5 Mo-6 Zr-4.5 Sn-Ti) and 18 Mo-Ti were performed in order to study microstructure-mechanical property relationships. Transmission electron microscopy was employed to delineate the effects that prior cold work and multiple aging steps produce in microstructure. The optimum combination of strength (230 ksi) and good ductility/toughness is obtained by cold work of the Beta-phase followed by preaging in the omega + Beta region and final aging in the alpha + Beta region to produce an extremely fine distribution of alpha-particles in the Beta-matrix. Results of an internal friction study on a series of Beta-Ti alloys containing various amounts of Mo and V with and without plastic deformation are also presented in order to describe the fundamental nature of the Beta-omega transformation. These results indicate the transformation to be of the 'atom shuttle' or displasive type. (Author).

Unsteady aerodynamics for advanced configurations. part vii. velocity potentials in non-uniform transonic flow over a thin wing( Book )
1 edition published in 1968 in English and held by 1 library worldwide
Two methods were outlined in detail, and one of them was mechanized, for calculating acoustic ray paths emanating from any point in a non-uniform transonic flow field surrounding a wing. It gives the ray path, and the time, for the minimum time of travel from the acoustic source point to the field point. The resulting velocity potential is also computed. It was necessary to establish an accurate representation of the flow characteristics in the field surrounding the wing. Some ray lines travel over the planform and into the surrounding flow field. It was established that once off the planform they do not return. Available methods predict phase lags based on the assumption that acoustic rays travel in straight lines. The results of the study show this to be a very poor approximation at transonic speeds. Therefore, it is recommended that the method presented in the report be fully developed for the purpose of calculating generalized forces on wings in harmonic motion at transonic speeds. A computer program that would predict these phase lags with reasonable accuracy, and the corresponding flutter characteristics and unsteady aerodynamic loads on a wing responding to externally applied forces, such as gusts, would fill an important gap in the available technology. (Author).

A critical examination of discrete lattice and dispersed barrier hardening( Book )
1 edition published in 1968 in English and held by 1 library worldwide
The paper examines two theories of thermally activated deformation of metals; i.e., the lattice (Peierls-Nabarro) and dispersed barrier hardening. The predictions of two hardening theories show considerable similarities. Only forecasts with respect to the impurity content dependence of the yield stress and activation volume are significantly different. Available data on low temperature deformation in alpha-Ti and body centered cubic metals have been considered. The presently available theories of lattice hardening cannot explain strong dependence of the yield stress of alpha-Ti and Mo on the interstitial content. In the case of other bcc metals, it is not possible to distinguish between these two types of hardening on an experimental basis. In fact, except in extremely pure materials, it is suggested that the two types of hardening may cooperate to control plastic flow. (Author).

Effect of Hydrogen on Internal Friction of Several Ti Alloys( Book )
1 edition published in 1975 in English and held by 1 library worldwide
A resonant bar apparatus employing a three-component piezoelectric composite oscillator system was used to make internal friction and modulus measurements in several titanium alloys in the range of 80 to 400K. Emphasis was placed on the alpha plus beta alloy, Ti-6Al-4V, but the study also included pure Ti, Ti-Al alloys (1, 3 and 10 at.%), Ti-6Al-6V-2Sn, Ti-8Al-1Mo-1V and Ti-17.5Mo alloys. The effect of hydrogen impurities on internal friction was investigated, and a Snoek-type relaxation peak was observed in beta-containing alloys. In the case of Ti-6Al-4V, the peak was found at 144K in the kilohertz frequency range with a relaxation strength of 0.0035/at.% hydrogen. The peak was absent in pure Ti, Ti-Al alloys or quenched Ti-6Al-4V alloy, indicating the need of bcc lattice. The peak was also observed using 10MHz pulse-echo internal friction measurements at 195K.