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在蠕变试验中,当前普遍采用的测量伸长的手段是将引伸杆卡在试样工作部分以外的头部或凸台上.用这种卡持方法测出的变形量还包括圆角过渡区的变形量.目前不少试验室对这部分附加的变形量是不考虑的.这就造成了不同试验机上得出的数据有差异.这些附加变形引进的是系统误差.对于系统误差,只要可能,都应消除.据英美的标准认为应对计算长度进行一定的修正.但不同材料、不同温度、应力、时间下附加变形量是不同的.因此对一种尺寸的试样不能得到一个单一的修正系数.现分几种情况计算:
In creep tests, the most commonly used measure of elongation at the present time is to place the extension rod in the head or boss beyond the working portion of the specimen, and the amount of deformation measured using this holding method also includes fillet transition Area of the deformation. At present, many laboratories on this part of the additional deformation is not taken into account.This led to different test machine data differences are derived.These additional deformation is the introduction of system error.For the system error, as long as May be eliminated.According to British and American standards that should be calculated length correction, but the different materials, different temperature, stress, additional deformation under different time.Therefore, a sample size can not get a single Correction factor. Now divided into several cases: