Simulating Fatigue Cracks Growth in Spiral Bevel Gears Part 10 docx

... give insight into the sensitivity of the crack trajectories to loading location. The predictions in Section 5.5 did not consider changes in the original contact locations during propagation. The increasing ... surfaceshowingassumedshapeof largecrack(dashedline). A few cyclesof crack growth arecarriedout using the methoddescribedin Section 3.2.3. Thismethod assumesmodeI dominantfatigue c...

Ngày tải lên: 11/08/2014, 20:21

... die of spiral bevel gears. The progression of research related to computer analysis of gears has led to the investigation of crack growth in spiral bevel gears. FEM models of spiral bevel gears can ... mating gears are mounted are a few of the distinguishing characteristics between the gear types. Gears with intersecting shafts are called bevel gears. The most co...

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... pictures. NASA/CR 2000- 2100 62 78 CHAPTER SEVEN: DISCUSSION AND SENSITIVITY STUDIES 7.1 Introduction In Chapter 5, fatigue crack growth in the OH-58 spiral bevel pinion under moving, non-proportional ... presenting data from an OH-58 spiral bevel pinion test. The test was conducted by NASA/GRC. EDM notches were introduced into the root of nine of the pinion teeth to serve as...

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... crack front is now NASAJCR 2000- 2100 62 2 NASA / CRm2000- 2100 62 Simulating Fatigue Crack Growth in Spiral Bevel Gears Lisa E. Spievak, Paul A. Wawrzynek, and Anthony R. Ingraffea Cornell University, ... tremendous increase in computing power. Section 1.2 summarizes recent research related to modeling gears numerically. Limited work has focused on predicting crack trajecto...

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... a variety of failures from tooth bending fatigue to spalling to rolling contact fatigue in both spur and spiral bevel gears, The effective case depth is defined as the depth to reach 50 RC. x[Coy ... row two. In the final row, or time step,tooth 1losescontactand tooth2 advancesinto thestageof singletoothcontact. It is seenin Figures2.8 and 2.9 that the contactareabetweenmating...

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... l, log(_l) ntrinsic Ul'Ve Figure 3.5: Schematic of fatigue crack growth rate data in Paris regime at different stress ratios collapsing into a single "intrinsic" curve. Using Paris' ... focus on crack growth in regime II. Crack initiationl smallcrack effects, and unstable Crack growth (regime III) Will be ignored. A seminal development in predicting fatigue...

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... scatter in fatigue crack growth rates at different stress ratios in AISI 9 310 steel. Table 4.2 contains the slopes and vertical intercepts from the lines in the figures. In addition, a linear least ... 33 1.00E-03 1.00E-04 1.00E-05 1.00E-06 1.00E-07 1.00E-08 1 10 100 AK [ksi *in °5] Figure 4.4: Fatigue crack growth rate data for AISI 9 310 steel in room temperature air...

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... 1.000 s,,°xloo 0 .100 10. 000 0 .100 10. 000 0 .100 10. 000 0 .100 10. 000 0 .100 10. 000 0 .100 10. 000 0 .100 10. 000 0 .100 10. 000 0 .100 10. 000 0 .100 10. 000 0 .100 0 .100 10. 000 0 .100 10. 000 0 .100 10. 000 0 .100 10. 000 0 .100 ... growth rate for AISI 9 310 in 250 ° oil; I¢ = 1. Table 4.2: Intrinsic and non-intrinsic fatigue crack growth rate parameters. C...

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... results in a constant kink angle for the load cycle. Since the ratio is changing in the spiral- bevel gear tooth, the predicted angle of propagation during the load cycle changes. A method to determine ... Non-Proportional Loading As shown in Section 5.3, a crack in a spiral bevel pinion tooth is subjected to non-proportional loading. As a result, conventional methods to predic...

Ngày tải lên: 11/08/2014, 20:21

... is concludedthatthemovingloadmethod'strajectoriesaremoreaccurate. In summary,insightsinto the intricaciesof modelingfatiguecrack growth in threedimensionsweregained. Preliminary stepstoward accuratelymodelingcrack growth ... trajectories in a spiral bevel pinion required expanding the state-of-the-art capabilities and theories for predicting fatigue crack growth rates a...

Ngày tải lên: 11/08/2014, 20:21