Simulating Fatigue Cracks Growth in Spiral Bevel Gears Part 7 potx

... 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...

Ngày tải lên: 11/08/2014, 20:21

... 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...

Ngày tải lên: 11/08/2014, 20:21

... FIVE: PREDICTING FATIGUE CRACK GROWTH TRAJECTORIES IN THREE DIMENSIONS UNDER MOVING, NON- PROPORTIONAL LOADS 47 5.1 Introduction 47 5.2 BEM Model 47 5.2.1 Loading Simplifications 49 5.2.2 Influence ... 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...

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...

Ngày tải lên: 11/08/2014, 20:21

... 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 ... OH-58 Spiral Bevel Gear Design Objectives In rotorcrafl applications, a primary source of vibration of the gear box is produced by the spiral bevel gears [Coy et al. 19 87...

Ngày tải lên: 11/08/2014, 20:21

... 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...

Ngày tải lên: 11/08/2014, 20:21

... crack growth rate for AISI 9310 in 250 ° oil; I¢ = 1. Table 4.2: Intrinsic and non-intrinsic fatigue crack growth rate parameters. C C* Test n [ (in/ cycle)/(ksi,ino.5).] [ (in/ cycle)/(ksi,inO :).] R ... 40.000 U 0.825 0.822 0 .71 6 0 .71 3 0.589 0.5 87 0. 474 0. 472 0.3 27 0.326 0.254 0.253 0.180 0.180 0.144 0.144 AKe£f 2.434 2.4 67 3.542 3.565 4.388 4.399 4 .71 4 4 .71 6 4.886...

Ngày tải lên: 11/08/2014, 20:21

... pictures. NASA/CR 2000-210062 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 ... at location C in Figure 6.9 (1 670 x). NAS A/CR 2000-210062 77 polishing might have resulted from rubbing of the crack faces while the gear was in operation or rubbing ag...

Ngày tải lên: 11/08/2014, 20:21

... crack growth rate C [ (in/ cycle)/(psi *in 5)]" 1.08e-13 2 .72 e- 17 5.49e-21 1.54e-5 6.19e-20 1.23e-5 model parameters. da/dN l° [in/ cycle] 9.30e-6 2.03e-6 Cycles /inch I Fatigue Life 1 1 07, 5 27 675 ,838 492,611 ... 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 contac...

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