Simulating Fatigue Cracks Growth in Spiral Bevel Gears Part 11 pdf

... 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

... tremendous increase in computing power. Section 1.2 summarizes recent research related to modeling gears numerically. Limited work has focused on predicting crack trajectories in spiral bevel gears. This ... CRm2000-210062 Simulating Fatigue Crack Growth in Spiral Bevel Gears Lisa E. Spievak, Paul A. Wawrzynek, and Anthony R. Ingraffea Cornell University, Ithaca, New...

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... 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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... 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 9310 steel. Table 4.2 contains the slopes and vertical intercepts from the lines in the figures. In addition, a linear least ... work in [FRANC3D 1999c], thegainin accuracydoesnotjustify thesignificantincreasein computationaltime. 3.4Chapter Summary This chapter covered theories of LEFM and fatigue pertin...

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... R=0.5 _Linear Curve Fit , , , i d , i , , i 10 100 AKef: [ksi *in °'5] Figure 4.7: Intrinsic fatigue crack growth rate for AISI 9310 in 250 ° oil; I¢ = 1. Table 4.2: Intrinsic and non-intrinsic fatigue ... intrinsic growth rate data for the AISI 9310 steel tests conducted in heated oil. da/dN as a function of R is plotted in Figure 4.8. The curve in Figure 4.8 shows that...

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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 ... also indicates which loading mode is driving the crack growth. Mode I dominant fatigue crack growth is associated with smaller ratios. Qian et al. [ 1996] studied mixed mode I a...

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... STUDIES 7.1 Introduction In Chapter 5, fatigue crack growth in the OH-58 spiral bevel pinion under moving, non-proportional loads was predicted. Chapter 6 presented experimental fatigue crack ... 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 starter...

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... 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