Torsion fatigue failure of bus drive shafts
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The mystery surrounding high failure rates in the drive shafts of a large municipal transit agency's fleet of 40 newly acquired articulated buses is investigated. The drive shafts were fabricated from a low-carbon (0.45%) steel such as AISI 5046. An examination of the drive shafts on all 40 buses is conducted, and 6 different drive shaft designs are identified among the fleet, but all of the failures, 14 in all, are limited to just one of the identified designs. Microscopic examination of the fracture surface of one of the failed drive shafts under a scanning electron microscope is conducted to determine the failure mode. Evidence of high-cycle fatigue is found, and a finite-element analysis is conducted to compare the maximum stress of the design exhibiting failures with the most common of the other designs that exhibits no failures. A fatigue life prediction is performed to determine just how much longer the expected fatigue life of the surviving design is compared to the design that suffered the early failures.
Keywordsfailure analysis fatigue analysis fatigue failure fatigue life variation fractography SEM
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- 1.Fractography and Atlas of Fractographs, vol. 9,Metals Handbook, 8th ed., American Society for Metals, Metals Park, OH, 1974, pp. 322–23.Google Scholar
- 2.J.E. Shigley:Theory of Machines and Mechanisms, McGraw-Hill Book Company, New York, NY, 1980, pp. 376–80.Google Scholar
- 3.“Technical Report on Low Cycle Fatigue Properties Ferrous and Non-Ferrous Materials—SAE J1099 Jun98”, SAE Information Report,Materials, Fuels, Emissions, and Noise, vol 1,Society of Automotive Engineers' Handbook, Society of Automotive Engineers, Warrendale, PA, 1999.Google Scholar
- 4.H.O. Fuchs:Metal Fatigue in Engineering, John Wiley & Sons, New York, NY, 1980.Google Scholar
- 5.Worldwide Guide to Equivalent Irons and Steels, 4th ed.,ASM Materials Data Series, ASM International, Materials Park, OH, 2000.Google Scholar
- 6.C. Boller:Materials Data for Cyclic Loading, Part B: Low-Alloy Steels, Materials Science Monographs, 42B, Elsevier, 1987.Google Scholar