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 Posted: Tue 2:51, 11 Jan 2011 Post subject: stivali ugg Engine Failure analysis of fuel supply |
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Engine Failure analysis of fuel supply conduit
, Fatigue crack initiation in the U-shaped surface of the inner tube or outer surface to the opposite side of the expansion, especially # 2, respectively, in the U-shaped tube lateral and medial side of a symmetrical distribution of the two large and one small fatigue zone, that lead to fatigue crack initiation and propagation of stress parallel to the U-shaped surface of the bending stress. U-shaped according to the fuel oil supply mains and the installation of conduit structure (Figure 1), this ring l2 Tong dry tube surface scuff marks zoom FgI2Magnifieati ~ mofab ~ ionmarkpipesurface¡¿ 4 nuts from the local indentation F14I internal regret '} nmarksinsidethe ¢ø the first port 1 Fu Kuo eg, Chen, Lv Fengjun, etc.: Engine Failure analysis of fuel supply conduit 33, the bending stress comes mainly from two aspects, one high pressure fuel oil from the hose the flow of the main ring, the ring will have an impact on oil stress so that oil ring movement, the roots of the u-shaped tube bending stress generated; fuel pulse, with a corresponding catheter in the u-shaped root produces alternating bending stress. Second, the catheter is U-structure, one end connected to the main oil ring, the other end connected to the nozzle # 12, installed on the ring main oil supply conduit 12 will inevitably exist in individual catheter assembly stress so u-tube open at the open end of the outward or inward compression, resulting in catheter fracture medial or lateral parts are subject to greater bending stress. Catheter fracture, the fracture location was misplaced on both sides (Figure 2), tighten the nut indentation also shows that there locally exists a large assembly of stress. Clearly the impact of fuel is relatively small due to bending stress, the fatigue crack growth,[link widoczny dla zalogowanych], although the main source of stress, but the impact of crack initiation Dl ~ d,[link widoczny dla zalogowanych],. The large number of assembly stress, a greater impact on the crack initiation is the cause of great stress catheter main reason for fatigue crack initiation. U-tube in the engine installed on the structure of the equivalent cantilever, the vibration should be along the direction perpendicular to the plane with the catheter, the engine car check also proved this point,[link widoczny dla zalogowanych], indicating that the vibration caused by tube vibration stress on the crack initiation and propagation of the stress direction inconsistent, and therefore contribute little to fault. Although the Explorer and fracture conduit between the fuel and sometimes there is interference, but because there are 3 oil explorer and other parts of touch, is vibration, therefore, work in the engine, fuel Explorer vibration is very small, almost imperceptible, and interference The gap between the formation of mainly small, fuel supply and the catheter tube along the direction perpendicular to the plane caused by vibration, so the interference between the two had no significant effect on fracture. In addition, the catheter does not exist weld welding, defects such as loose,[link widoczny dla zalogowanych], damaged the structural integrity, but also have a greater stress concentration on the crack initiation has a facilitating role. 4 Conclusions 1) The two engines the air the same as the direct cause of oil leakage are the main oil due to the nozzle ring 12 # fuel supply tube connected to the connection at the break caused. 2) The nature of the fault fuel supply conduit for the larger initial stress high cycle fatigue fracture, fatigue crack initiation in the u-shaped ducts inside or outside of the weld site. 3) The catheter tube assembly stress in fatigue crack big early lead to initiation of the main reasons; high pressure fuel pulse caused by impact and bending stress on the crack initiation also has some influence; tube weld welding defects exist on the crack initiation has a role in promoting . References [1] Fu Kuo such as. Zhang Zheng. Failure analysis techniques [J]. TESTING A physical volumes, 2005,4 l (4) :212-216. [2] Zhang Dong. Signs of mechanical failure analysis [M]. Beijing: National Defence Industry Press, 1996. [3] Shi Changxu, Chung Kwan Peng, Li successful. Dictionary of engineering materials in China (Volume 1) Materials Engineering Foundation [M]. Beijing: Chemical Industry Press, 2006. [4] Fu Kuo example, Zhang Zheng. Failure analysis (continued) [J]. TESTING A physical volumes, 2005.41 (6) :318-323. [5] Wang Hongying, Xiaxiang Tai, Wang Zhihong and so on. A certain type of machine analysis for cracked fuel oil [A]. Zhang Dong. National Aerospace Equipment Failure Analysis fifth conference proceedings [C]. Beijing: National Defence Industry Press ,2006.315-317. [6] Li Quan, Fu Kuo example, Xu Zhigang and so on. Aircraft Engine Failure Analysis of Stainless steel tube [J]. Materials Engineering, 2003,[link widoczny dla zalogowanych], (Suppl) :137-138. [7] Liu Changkui, Liu Hua. TAI5 titanium alloy welded joint properties and fracture behavior [J]. Failure Analysis and Prevention. 2006.1 (2) :45-48. Copyright Notice All contributors in this-t: 1 article, are considered to agree with the-t: 1 co-authorized use of the media. Publication royalties paid licensing fees are included. \
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