518 Matching Results

Search Results

Advanced search parameters have been applied.

Effects of Environment on the Low-Cycle Fatigue Behavior of Type 304 Stainless Steel

Description: The low-cycle fatigue behavior of Type 304 stainless steel has been investigated at 593 degrees C in a dynamic vacuum of better than 1.3 x 10⁻⁶ Pa (10⁻⁸ torr). The results concerning the effects of strain range, strain rate and tensile hold time on fatigue life are presented and compared with results of similar tests performed in air and sodium environments. Under continuous symmetrical cycling, fatigue life is significantly longer in vacuum than in air; in the low strain range regime, the effect of sodium on fatigue life appears to be similar to that of vacuum. Strain rate (or frequency) strongly influences fatigue life in both air and vacuum. In compressive hold-time tests, the effect of environment on life is similar to that in a continuous-cycling test. However, tensile hold times are nearly as damaging in vacuum as in air. Thus, at least for austenitic stainless steels, the influence of the environment of fatigue life appears to depend on the loading waveshape.
Date: December 1979
Creator: Argonne National Laboratory. Materials Science Division.
Partner: UNT Libraries Government Documents Department

Fatigue and Recuperation Curves under Varying Lengths of Intertrial Recovery Periods

Description: The purposes of this study were to investigate the effect that strength level had upon fatigue and recuperation under the two conditions of five- and thirty-second interval duration periods. Another purpose was to compare the results of this study to similar studies using male subjects in order to determine if women's response patterns to tests of strength were similar to those of men.
Date: August 1968
Creator: Osborne, Jacquelyn
Partner: UNT Libraries

Low-Frequency Fatigue-Crack Propagation in Type 304 Stainless Steel at 482 and 593°C

Description: This report presents results from an investigation on the low-frequency fatigue-crack growth behavior of Type 304 stainless steel at 482 and 593 C. Included were continuous-cycling tests with a triangular loading waveform, waveshape-effects tests employing slow-fast, fast-slow and square waveforms, creep-crack growth rate tests, and a block-loading test. The results are compared with similar test data from the literature, and the block-loading test results are compared with results predicted by integrating the relations for da/dN obtained under constant conditions.
Date: June 1980
Creator: Raske, D. T.
Partner: UNT Libraries Government Documents Department

Early detection of cracks resulting from fatigue stressing

Description: Report discusses an apparatus that may be used for indicating the formation of fatigue cracks or for following the progress of cracks. Details of the experiment and discussion of the way in which the deflection-crack area relationship may be used to monitor fatigue cracks are included.
Date: September 1944
Creator: Bennett, John A.
Partner: UNT Libraries Government Documents Department

An analysis of the fatigue life of an airplane wing structure under overload conditions

Description: From Introduction: "Fatigue life expectancy in normal transport operations was investigated in reference 1 and was found to be of equal importance with single-gust life. The effect of overload operation of transport airplanes on the probability of encountering single critical gusts was investigated in reference 2 and the frequency of critical gusts was found to increase rapidly with overload. The effect of overload operation on fatigue strength, however, has not heretofore been evaluated, hence the investigations of references 1 and 2 are combined herein to permit such evaluation and to determine the relative importance of fatigue and single-gust failures under conditions of overload operation."
Date: February 1946
Creator: Reisert, Thomas D
Partner: UNT Libraries Government Documents Department

Bending Fatigue Tests on Flattened Strand Wire Rope at High Working Loads

Description: Abstract: The U.S. Bureau of Mines established a wire rope research laboratory to examine the factors that affect the safety and the useful life of wire rope. In the most recent work, two 32-mm 6x27H flattened strand ropes were degraded on a bending fatigue machine. The two tests were run at constant loads of 285 and 347 kN or safety factors of 2.5 and 2. Nondestructive and tensile strength tests were performed on samples of the ropes to determine the relationship between rope deterioration and rope breaking strength. Neither the area loss nor the number of broken wires measured from nondestructive tests could be used as clear indicators of the loss of strength. However, it was found from the tensile tests for both rope specimens that the strength loss was associated with the reduction of breaking strain. This suggests that measuring the strain of many short sections of a rope in the elastic region may locate the high stress sections and thus determine the condition of the rope.
Date: 1995
Creator: Wang, Richard C. & Shapiro, David E.
Partner: UNT Libraries Government Documents Department

Bilinear Cyclic Stress-Strain Parameters for Types 304 and 316 Stainless Steel

Description: The bilinear cyclic stress-strain parameters for Types 304 and 316 stainless steel are described. The bilinear properties of solution-annealed and aged Type 304 stainless steel (heat 9T2796) and solution-annealed Type 3l6 stainless steel (heat 8092297) under cyclic-loading conditions at a strain rate of 8.6 x 10⁵ s⁻¹, total strain range between 0.2 and 0.8 percent, and temperatures from 22 to 593 degrees C were determined. The dependence of bilinear parameters on maximum strain epsilon and temperature is discussed.
Date: July 1978
Creator: Maiya, P. S.
Partner: UNT Libraries Government Documents Department

Mechanism of fatigue in micron-scale films of polycrystalline silicon for microelectromechanical applications

Description: Reported nearly a decade ago, cyclic fatigue failure in silicon thin films has remained a mystery. Silicon does not display the room temperature plasticity or extrinsic toughening mechanisms necessary to cause fatigue in either ductile (e.g., metals) or brittle (e.g., ceramics and ordered mintermetallic) materials.
Date: August 2, 2001
Creator: Muhlstein, C.L.; Stach, E.A. & Ritchie, R.O.
Partner: UNT Libraries Government Documents Department

Determining worst-case fatigue thresholds for grain-bridging ceramics

Description: A method for determining worst-case cyclic fatigue thresholds in grain-bridging ceramics by quantifying the role of bridging is demonstrated for a model alumina. Crack-growth properties for both long and short (< 2 mm) cracks emanating from machined notches (root radii, (rho) {approx}; 15 - 150 (mu)m) were investigated. When compared as a function of the applied stress-intensity range (delta K), growth rates (da/dN) were far higher and fatigue thresholds (Delta)KTH were markedly lower with short cracks, with growth being observable at the lowest driving forces for short cracks emanating from razor micronotches ((rho)is approximately equal to 15 (mu)m). For growth rates < 10-8 m/cycle, da/dN vs. (delta)K data for short cracks merged with the steady-state data for long cracks after {approx}2 mm of extension.
Date: October 7, 2002
Creator: Kruzic, J.J.; Yuan, R.; Canon, R.M. & Ritchie, R.O.
Partner: UNT Libraries Government Documents Department

Comparison of 43Sn/43Pb/14Bi Solder and Standard 60Sn/40Pb Solder by Thermocyclic Fatigue Analysis

Description: The thermocyclic fatigue behavior of the low-melting solder 43Sn/43Pb/14Bi has been investigated and compared to that of standard 60Sn/4OPb solder via metallographic analysis (using scanning electron microscopy) and evaluation of the degree of fatigue development (using a fatigue scale as a function of thermocycles). Specimens were subjected to shearing strains imposed by several hundred fatigue thermocycles. Both solder types fatigue by the same microstructural failure mechanism as described by other workers. The mechanism is characterized by a preferential coarsening of the solder joint microstructure at the region of maximum stress concentration where cracks originate.
Date: August 1991
Creator: Calderon, Jose Guadalupe
Partner: UNT Libraries

Fatigue case study and reliability analyses for wind turbines

Description: Modern wind turbines are fatigue critical machines used to produce electrical power. To insure long term, reliable operation, their structure must be optimized if they are to be economically viable. The fatigue and reliability projects in Sandia`s Wind Energy Program are developing the analysis tools required to accomplish these design requirements. The first section of the paper formulates the fatigue analysis of a wind turbine using a cumulative damage technique. The second section uses reliability analysis for quantifying the uncertainties and the inherent randomness associated with turbine performance and the prediction of service lifetimes. Both research areas are highlighted with typical results.
Date: December 31, 1994
Creator: Sutherland, H.J. & Veers, P.S.
Partner: UNT Libraries Government Documents Department

Biaxial Creep-Fatigue Behavior of Type 316H Stainless Steel Tube

Description: Biaxial creep-fatigue test data for Type 316 stainless steel tubes at 1100*Y are presented. The specimens were subjected to constant internal pressure and fluctuating axial strain with and without hold times in tension as well as compress ion. The results show that internal pressure significantly affects diametral ratchetting and axial stress range. Axial tensile hold is found to he more damaging than axial compressive hold even cinder a biaxial state of stress.
Date: April 1979
Creator: Majumdar, S.
Partner: UNT Libraries Government Documents Department

Comparative fatigue tests of riveted joints of Alclad 24S-T, Alclad 24S-T81, Alclad 24S-RT, Alclad 24S-T86 and Alclad 75S-T sheet

Description: Report discusses testing performed to determine the fatigue strength of various types of riveted and spot-welded joints in the following aluminum alloys: Alclad 24S-T, 24S-RT, 758-T, 24S-T81, and 24S-T86. Details of the experiment, tensile properties, and information about failure are provided.
Date: August 1945
Creator: Moore, R. L. & Hill, H. N.
Partner: UNT Libraries Government Documents Department

Piston-ring vibration and breakage

Description: Report presenting testing to determine the stresses and bending moments required to break pieces 1 inch or less in length from the ends of cast-iron, keystone, compression piston rings. Strain gages were used to determine the stress pattern for various modes of vibration. The maximum-stress points of vibrating piston rings were at the antinodes or points of maximum deflection.
Date: August 1945
Creator: Nettles, J. C. & Meyer, André J., Jr.
Partner: UNT Libraries Government Documents Department

Vibration survey of blades in 10-stage axial-flow compressor: 1: static investigation

Description: From Summary: "An investigation was conducted to determine the cause of failures in the seventh- and tenth-stage blades of an axial-flow compressor. The natural frequencies of all rotor blades were measured and critical-speed diagrams were plotted. These data show that the failures were possibly caused by resonance of a first bending-mode vibration excited by a fourth order of the rotor speed in the seventh stage and a sixth order in the tenth stage."
Date: January 31, 1949
Creator: Meyer, André J., Jr. & Calvert, Howard F.
Partner: UNT Libraries Government Documents Department

Investigation of the effect of impact damage on fatigue strength of jet-engine compressor rotor blades

Description: Report presenting an investigation to determine the effect of type and location of impact damage on the fatigue strength of jet-engine compressor blades. The most serious damage was found in the nicks at the leading and trailing edges in the vicinity of the maximum-vibratory-stress section of the airfoil. Results regarding stress distribution in the blades, fatigue of the damaged blades, the fatigue test results, the correlation of reduction in strength, an analysis of the results, and testing using reworked blades are provided.
Date: June 1956
Creator: Kaufman, Albert & Meyer, André J., Jr.
Partner: UNT Libraries Government Documents Department

Effect of crystal orientation on fatigue-crack initiation in polycrystalline aluminum alloys

Description: Report presenting testing demonstrating that fatigue cracks initiate in preexisting slip bands on planes parallel to planes from tests on large-grained specimens of 1100 and 5052 aluminum alloys. The resolved shear stress on the planes in crystal where fatigue cracks had developed were compared to uncracked crystals. Results regarding the location fatigue cracks, number of stress cycles observed, and differences of the crystals observed in the two types of aluminum alloys are provided.
Date: August 1957
Creator: Weinberg, J. G. & Bennett, J. A.
Partner: UNT Libraries Government Documents Department

Correlation of vibratory root failures and stress distribution in J65 compressor blades

Description: Report presenting an investigation of the stress distribution in the roots of the first three stages of the J6S axial-flow compressor in order to explain root failures experienced in service. Root failures were producible in the lab when high vibratory stresses were combined with simulated centrifugal loads. Results regarding fatigue tests on the original J6S blade roots and on two redesigned blade roots as well as a comparison of the different root designs are provided.
Date: September 8, 1955
Creator: Meyer, André J., Jr. & Kaufman, Albert
Partner: UNT Libraries Government Documents Department

Effect of variables in welding technique on the strength of direct-current metal-arc-welded joints in aircraft steel I: static tension and bending fatigue tests of joints in SAE 4130 steel sheet

Description: Report presenting testing of arc-welded butt joints in a 1/8-inch SAE 4130 steel sheet of aircraft quality under various conditions of welding and heat treatment in order to evaluate the effects of specific welding-technique factors on the strength of the joints. Results regarding static tension tests and fatigue tests are provided.
Date: July 1947
Creator: Voldrich, C. B. & Armstrong, E. T.
Partner: UNT Libraries Government Documents Department