应变切换点对材料屈服强度测量的影响

Effect of Strain Switching Point on Measurement of Material Yield Strength

屈服强度是金属材料重要的力学性能指标,它是工程上从静强度角度选择韧性材料的基本依据。不同的材料有着不同的弹性模量,表现在拉伸曲线图上就是拉伸曲线直线部分的斜率会各不相同。在进行屈服实验时,为了测得更准确的直线部分,采用在试样上捆绑引伸计的方法进行测量,但是试样最终会断裂。引伸计一直放在试样上会发生损坏,所以必须提前取下进行应变的过渡,取下引伸计时所对应的拉伸应变就是应变切换点。

Yield strength is an important mechanical properties index of metallic materials.It is the basic basis for selecting ductile materials from the angle of static strength in engineering.Different materials have different elastic modulus,the slope of straight part of the stretch curve is different.During the yield strength test,in order to measure the straight line more accurately,the method of binding the extensometer on the specimen is used,but the specimen eventually fractures.If the extensometer has been placed on the specimen all the time,it will be damaged,so it must be removed in advance for strain transition,the tensile strain corresponding to the removal of the extensometer is the strain switching point.