英语翻译Failure analysis,dimensional And Analysis,Applications O

英语翻译
Failure analysis,dimensional And Analysis,Applications Of Cams
Introduction
It is absolutely essential that a design engineer know how and why parts fail so that reliable
machines that require minimum maintenance can be designed.sometimes a failure can be
seriously,such as when a tire blows out on an automobile traveling at high speed.on the other
hands,a failure may be no more than a nuisance.an example is the loosening of the radiator hose
in an automobile cooling system.The consequence of this latter failure is usually the loss of some
radiator coolant,a condition that is readily detected and corrected.
The type of load a part.absorbs is just,as significant as the magnitude.generally speaking,
dynamic loads with direction reversals cause greater difficulty than static loads,and therefore,
fatigue strength must be considered.Another concern is whether the material is ductile or
brittle.for example,brittle materials are considered to be unacceptable where fatigue is involved.
Many people mistakenly interpret the word failure to mean the actual breakage of a
part.however,a design engineer must consider a broader understanding of what appreciable
deformation occur.A ductile material ,however will deform a large amount prior to
rupture .excessive deformation,without fracture,may cause a machine to fail because the
deformed part interfere with a moving second part .therefore,a part fails(even if it has not
physically broken)whenever it no longer fulfills its required function.Sometimes failure may be
due to abnormal friction or vibration between two mating parts.Failure also may be due to a
phenomenon called creep ,which is the plastic flow of a material under load at elevated
temperature.In addition ,the actual shape of a part may be responsible for failure.For example,
stress concentration due to sudden changes in contour must be taken into account.Evaluation of
stress considerations is especially important when there are dynamic loads with direction reversals
and the material is not very ductile.
In general,the design engineer must consider all possible modes of failure,which include the
following.
---------stress
---------deformation
---------wear
---------corrosion
---------vibration
---------environmental damage
---------loosening of fastening devices
The part sizes and shapes selected also must take into account many dimensional factors that
produce external load effects,such as geometric discontinuities,residual stresses due to forming
of desired contour,and the application of interference fit joint.
Cams are among the most versatile mechanisms available.An cam is simple two-member device-dependent.The input member is the cam itself,while the output member is called the follower .through the use of cams,a simple input motion can be modified into almost any
conceivable output motion that is desired.Some of the common applications of cams are
-------camshaft and distributor shaft of automotive engine
-------production machine tools
-------automatic record players
-------printing machines
-------automatic washing machines
-------automatic dishwashers

失败分析,尺寸和分析,凸轮的应用
介绍
它是绝对必要的设计工程师知道怎么并且为什么零件失灵以便可靠
要求极小的维护的机器可能有时被设计失败可能是
严重,譬如当轮胎力量消失在汽车旅行在高速.在另一边
手,失败也许是没有比讨厌.例子是松懈幅射器水喉
在汽车冷却系统.这后者失败的后果通常是一些的损失
幅射器蓄冷剂,被查出和欣然被改正的情况.
part.吸收的类型装载象巨大是正义的,一样重大一般讲话,
动态装载以方向逆转导致更加巨大的困难比静态负载,和因此,
疲劳力量必须被考虑.其它关心是是否材料柔软或
易碎例如,易碎的材料认为是不能接受的疲劳是包含的地方.
许多人错误地解释词疏忽意味a 实际破损
part.然而,设计工程师必须考虑更加宽广的理解对什么看得出
变形发生.柔软材料,然而将扭屈一笔巨额在之前
爆裂excessive 变形,没有破裂,可以导致机器失败因为
被扭屈的部份干涉一行动的第二部份therefore,零件fails(even 如果它没有
broken)whenever 它不再完全履行它必需的作用.有时失败也许是
由于反常摩擦或振动在二个配件之间.失败也许还归结于a
现象叫蠕动,是材料塑料流程在装载之下在举起
温度.另外,零件的实际形状也许负责对失败.例如,
重音集中由于突然的变化在等高上必须被考虑到.评估
重音考虑特别重要当有动态装载以方向逆转
并且材料不非常柔软.
总之,设计工程师必须考虑所有可能的失效状态,包括
随后而来.
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