金属材料割线模量峰值与其弹性极限的相关性

Correlation between peak secant modulus value and elastic limit of metallic materials

为了快速确定金属材料单轴应力状态下的弹性极限或屈服应力,对高碳钢与低碳钢进行了拉伸和压缩试验,绘制了割线模量-应变曲线,分析了割线模量峰值与弹塑性变形的相关性.结果表明,在应力-应变全过程中割线模量存在明显峰值,且达到峰值后呈现衰减特征.峰值所在的位置与其弹性极限具有较为稳定的对应关系,因而通过确定该峰值所在位置可以间接确定弹性极限.割线模量峰值与弹性极限均可能受到加载速度、边界条件或应力状态等因素的影响,还可能存在尺寸或形状效应.

In order to rapidly determine the elastic limit or yield stress of metallic materials under uniaxial stress state,the tensile and compressive tests for both high carbon steel and low carbon steel were conducted,the secant modulus-strain curves were plotted,and the correlation between the peak secant modulus value and elastic-plastic deformation was analyzed. The results indicate that in the whole stress-strain process,the secant modulus has an obvious peak value,and the peak value shows attenuation characteristics. There is a stable corresponding relationship between the location of peak value and its elastic limit. Thus,the elastic limit can be indirectly determined through determining the location of peak value. The peak value and elastic limit may be affected by such factors as loading speed,boundary condition or stress state,and they may also have size effect or shape effect.