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Factors That Affect Operational Reliability of Turbojet Engines

Description: The problem of improving operational reliability of turbojet engines is studied in a series of papers. Failure statistics for this engine are presented, the theory and experimental evidence on how engine failures occur are described, and the methods available for avoiding failure in operation are discussed. The individual papers of the series are Objectives, Failure Statistics, Foreign-Object Damage, Compressor Blades, Combustor Assembly, Nozzle Diaphrams, Turbine Buckets, Turbine Disks, Rolling Contact Bearings, Engine Fuel Controls, and Summary Discussion.
Date: January 31, 1956
Creator: Lewis Laboratory Staff
Partner: UNT Libraries Government Documents Department

Handbook of Structural Stability Part 4: Failure of Plates and Composite Elements

Description: Available theories on failure of flat plates are reviewed, and test data on the postbuckling behavior, effective width, and failure of flat curved plates are correlated. Test data on the crippling strength of various formed and extruded shapes are reviewed, from which a generalized method of crippling analysis is formulated. This analysis is then applied to a variety of sections and materials in common use.
Date: August 1957
Creator: Gerard, George
Partner: UNT Libraries Government Documents Department

Designation of Global 'Too Big To Fail' Firms

Description: This report provides background on the the Financial Stability Board's (FSB) designation process for systemically significant financial institutions, but takes no position on any potential benefits or shortcomings of that process.
Date: October 29, 2015
Creator: Miller, Rena S. & Jackson, James K.
Partner: UNT Libraries Government Documents Department

The Federal Deposit Insurance Corporation (FDIC): Summary of Actions in Support of Housing and Financial Markets

Description: This report discusses recent actions taken by the Federal Deposit Insurance Corporation (FDIC) in support of housing and financial markets, including: a temporary increase in deposit insurance as required by the Emergency Economic Stabilization Act of 2008 (P.L. 110-343), the resolution of bank failures, the development of the Temporary Liquidity Guarantee Program (TLGP), and efforts to reduce foreclosures.
Date: March 5, 2009
Creator: Gonzales, Oscar R. & Getter, Darryl E.
Partner: UNT Libraries Government Documents Department

Application of Statistical Methods to Study of Gas-Turbine Blade Failures

Description: Note presenting an investigation conducted to determine the applicability of statistical methods as an approach to the evaluation of materials for use in gas turbines by determining the frequency distribution of time until failure of gas-turbine blades. Two wheels, each incorporating 142 inserted blades of a cast cobalt-base heat-resistant alloy, were tested. The results indicated that the time for first failure may not generally be taken as an accurate indication of the performance of the average blade.
Date: June 1948
Creator: Hoffman, Charles A. & Ault, G. Mervin
Partner: UNT Libraries Government Documents Department

A Theory for Primary Failure of Straight Centrally Loaded Columns

Description: "A theory of primary failure of straight centrally loaded columns is presented. It is assumed that the column cross section and the load are constant throughout the length. Primary failure is defined as any type of failure in which the cross sections are translated, rotated, or translated and rotated but not distorted in their own planes" (p. 141).
Date: August 17, 1936
Creator: Lundquist, Eugene E. & Fligg, Claude M.
Partner: UNT Libraries Government Documents Department

Experimental Study of Torsional Column Failure

Description: "Thirty-three 24ST aluminum-alloy 2- by 2- by 0.10-inch channels, with lengths ranging from 10 to 90 inches were tested at Stanford University in compression to obtain an experimental verification of the theoretical formulas for torsional failure developed by Eugene E. Lundquist of the N.A.C.A. The observed critical loads and twist-axis locations were sufficiently close to the values obtained from the formulas to establish the substantial validity of the latter. The differences between observed and computed results were small enough to be accounted for by small and mostly unavoidable differences between actual test conditions and those assumed in deriving the formulas" (p. 1).
Date: October 1939
Creator: Niles, Alfred S.
Partner: UNT Libraries Government Documents Department

Tests of Aerodynamically Heated Multiweb Wing Structures in a Free Jet at Mach Number 2: An Aluminum-Alloy Model of 40-Inch Chord With 0.125-Inch-Thick Skin

Description: Report presenting testing of a 5-percent-thick 2024-T3 aluminum-alloy multiweb wing (MW-1-(2)) at a Mach number of 2 under simulated supersonic flight conditions. The wing experienced dynamic failure as a result of catastrophic flag-waving flutter due to the combined action of aerodynamic heating and loading. Results regarding model temperatures, experimental pressures, strain results, accelerometer, and model failure are provided.
Date: June 23, 1958
Creator: Griffith, George E. & Miltonberger, Georgene H.
Partner: UNT Libraries Government Documents Department

Susceptibility to Welding Cracking, Welding Sensitivity, Susceptibility to Welding Seam Cracking, and Test Methods for These Failures

Description: "In the years after the First World war a very rapid development, which even today has by no means come to an end, took place in the field of welding; here also, as in most technical innovations, failures made their appearance. Thereupon comprehensive Investigations were undertaken by steel manufacturers and consumers with cooperation of the authorities. In most cases the reasons for failure could be determined and eliminated and further occurrences avoided by the use of new test methods" (p. 1).
Date: June 1949
Creator: Zeyen, K. L.
Partner: UNT Libraries Government Documents Department

Investigation of the Kansas City Hyatt Regency Walkways Collapse

Description: Report issued by the National Bureau of Standards over investigations conducted on construction failures of two suspended walkways in a Kansas City hotel. Details of the investigation are presented. This report includes tables, illustrations, and photographs.
Date: May 1982
Creator: Marhsall, Richard D.; Pfrang, E. O.; Leyendecker, Edgar V.; Woodward, K. A.; Reed, R. P.; Kasen, M. B. et al.
Partner: UNT Libraries Government Documents Department

Twisting of Thin Walled Columns Perfectly Restrained at One End

Description: "Proceeding from the basic assumptions of the Batho-Bredt theory on twisting failure of thin-walled columns, the discrepancies most frequently encountered are analyzed. A generalized approximate method is suggested for the determination of the disturbances in the stress condition of the column, induced by the constrained warping in one of the end sections" (p. 1).
Date: March 1938
Creator: Lazzarino, Lucio
Partner: UNT Libraries Government Documents Department

Effectiveness of Ceramic Coatings in Reducing Corrosion of Five Heat-Resistant Alloys by Lead-Bromide Vapors

Description: Note presenting testing to determine whether lead compounds in the combustion products of high-octane fuel are a contributing factor in causing failures of the heat-resistant alloy parts in aircraft exhaust systems. To obtain answers for five heat-resistant alloys, a test was devised in which the alloy specimens in an uncoated condition, in a preoxidized condition, and with three different ceramic coatings were exposed for 6 hours to lead-containing vapors in an air atmosphere at 3 different temperatures.
Date: June 1951
Creator: Moore, Dwight G. & Mason, Mary A.
Partner: UNT Libraries Government Documents Department

Wind-tunnel investigation of a 1/6-scale model of the Bumblebee XPM missile at high subsonic speeds

Description: Report presenting the results of an investigation of a model of the Bumblebee XPM missile to determine the causes of booster-fin failures on full-scale missiles. Results indicated that failures of the fins were due to launching shoes which caused the missile to try at increasingly negative angles of attack as the Mach number increased.
Date: December 11, 1950
Creator: Nelson, Warren H.
Partner: UNT Libraries Government Documents Department

Three Essays in Business Failure

Description: This dissertation consists of three essays exploring market reactions to business failure. In the first essay, the filing strategies are divided into three basic types, voluntary, involuntary and prepackaged. The second essay provides insight into industry wide factors impacting assimilation of information by the market. The third essay provides a view of the GARCH-M model in measuring a risk premium as a firm approaches bankruptcy.
Date: May 1997
Creator: Theis, John D. (John Dennis)
Partner: UNT Libraries

Investigation of mechanisms of blade failure of forged Hastelloy B and cast Stellite 21 turbine blades in turbojet engine

Description: An investigation was conducted to study the mechanisms of blade failure of forged Hastelloy B and cast Stellite 21. The blades were mounted in a 16-25-6 alloy rotor and subjected to 20-minute cycles consisting of 15 minutes at rated speed and approximately 5 minutes at idle. The first failures of the Hastelloy B and Stellite 21 blades were probably the result of excessive vibratory stresses and occurred after 14.25 and 16.75 hours, respectively. After 28.75 hours of operation, all but 3 of the original 25 Hastelloy B blades had either failed or contained stress-rupture-type cracks and four of the original 27 Stellite 21 blades contained stress-rupture-type cracks.
Date: August 22, 1951
Creator: Yaker, C.; Robards, C. F. & Garrett, F. B.
Partner: UNT Libraries Government Documents Department

The Comparison and Evaluation of Three Fiber Composite Failure Criteria

Description: Three specific failure criteria for the transversely isotropic fiber composite case will be discussed. All three use the polynomial expansion method. The three criteria are the Tsai-Wu criterion, the Hashin criterion and the Christensen criterion. All three criteria will be given in forms that admit direct and easy comparison, which has not usually been done. The central differences between these three criteria will be discussed, and steps will be taken toward the evaluation of them.
Date: February 8, 2005
Creator: Christensen, R M
Partner: UNT Libraries Government Documents Department