John Ruschau - Profile on Academia.edu (original) (raw)

Papers by John Ruschau

Complete Fatigue Crack Growth Rate Curves for Aluminum Alloy 2124-T851 Including Typical Crack Growth Models

Determination of Test Technique Influence on K sub ISCC Values for Aluminum 7075-T651

Fatigue Crack Growth Rate Data for Aluminum Alloy 6061-T651 Plate

... to August 1983. The author, Mr. John J. Ruschau, would like to extend special recognition to ... more ... to August 1983. The author, Mr. John J. Ruschau, would like to extend special recognition to Messrs. Richard Marton and John Eblin of the University of Dayton for performing all mechanical testing. ... Results shown in both the fi(tjnreý and t., il,,:; in'ic,,tit( no ...

Mechanical Property Evaluation of P/M (Powder-Metallurgy) Aluminum 7090-T7E71 Plate

Spectrum Fatigue Crack Growth Rate Characteristics of PM (Powder Metallurgy) Aluminums 7090 and 7091

Mechanical Property Data for Aluminum Alloy 2419-T851 Plate

The public reporting burden for this collection of information is estimated to average 1 hour per... more The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS.

Mechanical Property Data on P/M Aluminum X7091-T7E69 Extrusion

A mechanical property investigation was performed on aluminum X7091-T7E69 extrusion, a recently d... more A mechanical property investigation was performed on aluminum X7091-T7E69 extrusion, a recently developed alloy produced using powder-metallurgy technology. Properties examined were tensile and compression, smooth and notched fatigue, fracture, fatigue crack growth, and ...

The stress-level effect on fatigue-crack growth under constant-amplitude loading

International Journal of Fatigue, Sep 1, 2007

The fatigue-crack-closure concept has been successfully used with stress-intensity factors to pre... more The fatigue-crack-closure concept has been successfully used with stress-intensity factors to predict the growth of cracks under a wide variety of load histories and in complex crack configurations. Both test and crack-closure analyses have shown that the stress-intensity-factor-range-against-rate curves are affected by the stress ratio (R), the applied stress or load level (Smax or Pmax), and the crack-front constraint (plane-stress or plane-strain behavior). However, most life-prediction codes use only linear-elastic fracture mechanics (LEFM) concepts, which neglect stress-level effects, to make life predictions. Thus, under some loading conditions, such as negative R ratios or high-applied stress levels, non-conservative life predictions are made using only LEFM procedures.Fatigue-crack-growth tests have been conducted on middle-crack tension M(T) specimens made of 2024-T3 thin-sheet (B = 2.3 mm) aluminum alloy over a wide range in applied stress levels (0.1–0.5 times the flow stress of the material) and for two stress ratios (R = 0.05 and −1). The FASTRAN life-prediction code, using either the crack-closure model or LEFM procedures, and the AFGROW code, which uses only LEFM procedures, were used to make crack-growth predictions from an initial crack size to failure in the M(T) specimens. The results from AFGROW and FASTRAN, using LEFM procedures, agreed very well with each other. The crack-closure model predicted all results with ±20%, whereas, the codes using LEFM procedures (neglecting stress-level effects) resulted in non-conservative life predictions as large as a factor-of-3 from the test results.

An Investigation into Impacting Techniques for Simulating Foreign Object Damage and Their Influence on the Fatigue Limit Strength of Ti-6Al-4V

... Steven R. Thompson United States Air Force Research Laboratory Materials and Manufacturing Di... more ... Steven R. Thompson United States Air Force Research Laboratory Materials and Manufacturing Directorate AFRL/MLSC steven.thompson@wpafb.af.mil TheodoreNicholas United States Air Force Institute of Technology AFIT/ENY ...

An Assessment of Laboratory Techniques for Simulating Foreign Object Damage on a Leading Edge Geometry

... Dayton, Dayton, OH, August, 2002. [4] Mall, S., Hamrick, JL, II and Nicholas, T., &am... more ... Dayton, Dayton, OH, August, 2002. [4] Mall, S., Hamrick, JL, II and Nicholas, T., &amp;quot;High Cycle Fatigue Behavior of Ti-6A1-4V with Simulated Foreign Object Damage,&amp;quot; Mech. of Mat., 33, 2001, pp. 679-692. [5] Martinez, CM, Birkbeck ...

Int J Impact Eng, 2001

The fatigue behavior of Ti-6Al-4 V samples that have undergone foreign object damage (FOD) was in... more The fatigue behavior of Ti-6Al-4 V samples that have undergone foreign object damage (FOD) was investigated. A unique test specimen configuration that replicates the leading edge of a typical fan blade was ballistically shot with 1.0 mm diameter glass spheres to simulate actual FOD. Samples were shot at various incident angles to investigate the influence of impact angle on fatigue strength. Two stress ratios were examined: R=0.1 and 0.5. Attempts were made to correlate the measured damage (macro-/microscopic) to the debit in fatigue strength. The FOD impact sites of fatigue samples were examined prior to testing via a scanning electron microscope (SEM); post-test examinations of the fatigue initiation sites were also performed on selected test samples. Subsurface or internal damage resulting from the FOD was also investigated from precision micro-sectioning of selected samples. Off-angle impacts were found to be more detrimental than head-on (0°) impacts. Fatigue strength losses, some as high as 50%, showed little or no correlation with leading edge thickness or depth of notch.

Weldalite (trademark) 049 (Al 2095-T8): Anisotropy Effects at Cryogenic Conditions

... John J. Ruschau University of Dayton Research Institute 300 College Park Dayton OH 45469-0136... more ... John J. Ruschau University of Dayton Research Institute 300 College Park Dayton OH 45469-0136 S Kumar V. Jata Materials Integrity Branch Systems Support Division August 1993 ... THEODORE J. INHART , Chief Engineering and Design Dama Materials Engineering Branch ...

$Research paper thumbnail of Role of delamination toughening and fracture mode transition on the cryogenic fracture toughness of 2091 AlLi alloy$

Scripta Metallurgica et Materialia, 1990

~Dtroductlon Aluminum-lithlum alloys have of=an been associated with higher strength and fracture... more ~Dtroductlon Aluminum-lithlum alloys have of=an been associated with higher strength and fracture toughness at cryogenic temperatures as compared to those at ambient temperatures. Enhancements in toughness and ductility, most often no=ed in the cross-graln orlencacions (i.e., L-T and T-L), are in the range of five to 90 percent, while improvements in strength, reported for all A1-LI alloys, are typically on the order of 25 percent. Combined with the fact that AI-LI alloys can provide substantial reductions in struc=ural weight, this interesting cryogenic behavior has generated a =remendous interest for use in liquid fuel (i.e., liquid hydrogen and oxygen) storage applications.

Quick Reaction Evaluation of Materials and Processes (QRE). Task Order 0008: Titanium Billet Characterization and Materials Properties Development (Nonconforming Titanium) - Executive Summary

Fracture Toughness and Failure Mechanisms in Commercial 2091 A1-Li Sheet at Cryogenic Temperatures

Metallurgical and Materials Transactions A, 2000

Aluminum alloy 7050 was friction-stir welded (FSW) in a T7451 temper to investigate the effects o... more Aluminum alloy 7050 was friction-stir welded (FSW) in a T7451 temper to investigate the effects on the microstructure and mechanical properties. Results are discussed for the as-welded condition (as-FSW) and for a postweld heat-treated condition consisting of 121 ЊC for 24 hours (as-FSW ϩ T6). Optical microscopy and transmission electron microscopy (TEM) examination of the weld-nugget region show that the FS welding process transforms the initial millimeter-sized pancake-shaped grains in the parent material to fine 1 to 5 m dynamically recrystallized grains; also, the FS welding process redissolves the strengthening precipitates in the weld-nugget region. In the heat-affected zone (HAZ), the initial grain size is retained, while the size of the strengthening precipitates and of the precipitatefree zone (PFZ) is coarsened by a factor of 5. Tensile specimens tested transverse to the weld show that there is a 25 to 30 pct reduction in the strength level, a 60 pct reduction in the elongation in the as-FSW condition, and that the fracture path is in the HAZ. The postweld heat treatment of 121 ЊC for 24 hours did not result in an improvement either in the strength or the ductility of the welded material. Comparison of fatigue-crack growth rates (FCGRs) between the parent T7451 material and the as-FSW ϩ T6 condition, at a stress ratio of R ϭ 0.33, shows that the FCG resistance of the weldnugget region is decreased, while the FCG resistance of the HAZ is increased. Differences in FCGRs, however, are substantially reduced at a stress ratio of R ϭ 0.70. Analysis of residual stresses, fatiguecrack closure, and fatigue fracture surfaces suggests that decrease in fatigue crack growth resistance in the weld-nugget region is due to an intergranular failure mechanism; in the HAZ region, residual stresses are more dominant than the microstructure improving the fatigue crack growth resistance.