英语翻译In any engineering the individual components or members

英语翻译
In any engineering the individual components or members will be subjected to external forces arising from the service conditions or environment in which the component works.
There are a number of different ways in which load can be applied to a member .loads may be classified which respect to time.
(1)A static load is a gradually applied load for which equilibrium is reached in a relatively short time.
(2)A sustained load is a load that is constant over a long period of time,such as the weight of a structure (called dead load).This type of load is treated in the same manner as a static load; however,for some materials and conditions of temperature and stress,the resistance to failure may be different under short time loading and under sustained loading.
(3)An impact load is a rapidly applied load (an energy load).Vibration normally results from an impact load,an impact load,and equilibrium is not established until the vibration is eliminated,usually by natural damping forces.
(4)A repeated load is a load that is applied and removed many thousands of times.
(5)A fatigue or alternating load is a load whose magnitude and sign are changed which time.
It has been noted above that external force applied to a body in equilibrium is reacted by internal forces set up within the material.
Stress(δ)=load/area=P/A (1)
Stressδmay thus be compressive or tensile depending on the nature of the load and will be measured in units of newtons per square meter(N/m²)or multiples of this.
If a bar is subjected to an axial load,and hence a stress,the bar will change in length.If the bar has an original length L and changes in length by an amount δL,the strain produced is defined as follows:
Strain(ε)=change in length/original length=δL/L (2)
Since,in practice,the extensions of materials under load are very small,it is often convenient to measure the strains in the form of stainⅹ 10 -6,i.e.microstrain,when the symbol used becomes με.
Tensile stresses and strains are considered positive in sense.Compressive stresses and stains are considered negative in sense.Thus a negative strain produces a decrease in length.
这是关于材料力学应力与应变的文章，我只会翻译单词，不要用金山快译，这里牵扯到专业用语，

在任何工程上,单独的部件和零件,都受到由运行条件或部件工作的环境而产生的外力.荷载作用到零件上有许多不同的途径.就作用时间而论,荷载可被分为:
(1)静荷载.它是定量作用的,在相对短的时间内达到的均衡荷载;
(2)持续荷载.它是长时间作用的不变荷载;诸如,构件的重量(称作自重).这种形式的荷载,通常作为静荷载一样来处理.但是,对于某些材料和温度及应力条件,在短时间荷载和持续荷载下,其耐破断性是不同的.
(3)冲击荷载.它是快速作用的荷载(动荷载).通常,振动是由冲击荷载引起的.一般在自然阻尼力的作用下,振动消失后,冲击荷载才变成均衡荷载.
(4)重复荷载.它是一种动作千万次地作用的荷载.
(5)疲劳或交替作用的荷载.这种荷载的大小和方向是随时改变的.上面指出的外力,均衡地作用到物体上,由于材料内力的影响,均衡地作用到物体的外力产生反作用力.(下面,都译了;为什么不见了).应力(sigma)=荷载/面积=P/A (1).根据材料的性质,应力(sigma)有压缩和拉伸;以每平方米作用的牛顿力(N/m2)为单位或者乘上该数来量度.如果,一杆件受轴向力,从而产生应力;该杆件的长度将改变.若杆件的原长为 L ,长度变化为 (读:delta )L ;产生的应变定义如下:应变(epsilon)=长度变化/原长=(delta L) /L (2).
实际上,由于在荷载下材料的延伸很小,为方便常常以应变 X 10 9 即:微应变的形式来量度应变;这时,所用符号变为:(读:Mu-epsilon).
在意义上,拉应力和应变被认作是正的;压应力和应变是负的;因此,压应变是长度减小.