| Summary: | 碩士 === 崑山科技大學 === 企業管理研究所 === 104 === Most military helicopters in Taiwan have been serviced for several years; however, parts or accessories of helicopter have likely been used for more than two or three decades since production and shipping to Taiwan. It is afraid that the crack of metals parts or accessories will unexpectedly occur at any time. Therefore, it is the subject of the study to analyze the potential reasons of the crack of metal accessories in helicopters by using fishbone diagram and Fault Tree Analysis techniques.
By literature review and soliciting experts opinions, a fishbone diagram shows there are six categories or 12 factors which cause the crack of metal: 1)machine-2 factors,2)human-2 factors,3)management-2 factors,4)methods-1 factors,5)material-3 factors, and the last 6)others-2 factors. In addition, by relating these factors, an FTA diagram is constructed and further, Boolean algebra is employed to get several important points. The most probable factor of causing cracks is “material,” which takes most frequency of occurrences of cracks. That means, if the factor “material” is controlled, the probability of occurrence of crack will significantly be reduced. Further, if the second factor, machine and human, can be solved simultaneously, no crack will occur. Besides, the study also focuses on the problems of nut brackets and glare shields. The study proposes suggestions so that problems can be improved. On the aspect of nut brackets, when jacking lever, the study recommends that a leader had better orders to make both technicians be able to slowly put pressure on jack, which could protect nut brackets from the crack causing stress concentration or uneven pressure on the wake of suddenly going up and down. On the other hand, the study also suggests that adding rubber packing between washer and glare shield. Because rubber packing is soft, it enables to absorb the shake of helicopter and reduce the friction between glare shield and washer. This way will decrease the probability of crack. It is expected that the conclusions will be helpful in preventing the helicopter from occurrence of crack in advance.
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