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

Papers by John Ruschau

... 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 ...

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 ...

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.

... 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 ...

... 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., "High Cycle Fatigue Behavior of Ti-6A1-4V with Simulated Foreign Object Damage," 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.

... 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 ...

Scripta Metallurgica et Materialia, 1990

Metallurgical and Materials Transactions A, 2000

... 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 ...

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 ...

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.

... 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 ...

... 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., "High Cycle Fatigue Behavior of Ti-6A1-4V with Simulated Foreign Object Damage," 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.

... 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 ...

Scripta Metallurgica et Materialia, 1990

Metallurgical and Materials Transactions A, 2000