英语翻译Shafts with circular cross section are invariably used f

英语翻译
Shafts with circular cross section are invariably used for transmission of power.The most common cause
of failure of these shafts is fatigue.In order for fatigue to occur,a cyclic tensile stress and a crack initiation
site are necessary.In general,the shafts in power plant systems run with a steady torsion combined with
cyclic bending stress due to the self-weight bending during rotation or possible misalignment between
journal bearings [1].
Thus,these rotating components are susceptible to fatigue by the nature of their operation and the fatigue
failures are generally of the rotating-bending type [2].The sites on shafts where fatigue cracks may
initiate are at the stress concentrations occurring at the keyway root radius and sharp changes in crosssectional
area of the shaft.In spite of the preventive measures taken during the design itself to minimise
stress concentrations at these geometrical irregularities,fatigue failures can still occur due to degradation
of shafts due to various other reasons [3].In this paper,a case study on the fatigue fracture of a crankshaft
of an aircraft engine is described.
An aircraft engine was withdrawn from service because of unusual noise during climb.The aircraft was
powered by twin piston engines and,therefore,could land safely with the help of the other engine.Strip
examination of the failed engine disclosed that the crankshaft had fractured into three pieces.The fracture
had occurred along the webs at the No.2 and No.3 journals (Fig.1).The crankshaft had completed a total
of 1460 h in service and 262 h since last overhaul.The magnetic particle inspection of the shaft during
overhaul did not reveal any defects in the critical areas either in the longitudinal or transverse direction.
The complex shaped crankshaft was machined from an alloy steel forging of SAE 4340 grade and case
hardened.The incident was reported to have occurred for the third time.In the earlier two cases also,the
fracturing was exactly similar and at identical locations [4].

轴以圆横断面为力量传输不变地使用.这些轴的失败的同道会是疲劳.为了疲劳发生,循环张应力和裂缝启蒙.一般来说,轴在能源厂系统奔跑以平稳的扭力与循环弯曲应力结合了由于弯曲在自转或可能的不同心度期间的自已重量之间.因此,这些转动的组分是易受疲劳由他们的操作和疲劳的本质.站点在轴,疲劳裂纹也许创始以发生在键槽根部半径和锐利的应力集中改变在在轴的crosssectional区域.竟管在设计采取的预防措施期间使应力集中减到最小在这些几何不规则性,疲劳失效可能仍然发生由于轴的退化由于各种各样的原因.在本文,关于飞机发动机的曲轴的疲劳断口的一个专题研究被描述.
飞机发动机从服务被撤出了由于异常的噪声在攀登期间.航空器由双胞胎活塞引擎供给动力,并且,因此,能在另一个引擎帮助下安全地登陆.剥离考试不合格的引擎透露曲轴破碎了入三个片断.破裂沿网发生了在没有.2和没有.3本学报.
因为前翻修,曲轴在使用中完成了共计1460 h和262 h.轴的磁性粒子检查在检修期间在临界面积没有显露任何瑕疵在纵向或横向方向.复杂形状的曲轴从SAE 4340等级和案件合金钢锻件被硬化的用了机器制造.事件报告第三次发生了.在也更加早期的二个案件,破碎确切地是相似和在相同地点.