巴西圆盘劈裂应变解

Strain Solutions of Brazilian Splitting Test

巴西圆盘试验(劈裂试验)只有平面问题的应力解,应变须经由本构方程计算,模量的取值则对计算应变有较大影响。针对该问题,假设劈裂过程中,试件为椭圆,根据几何关系推导了由竖向位移、试件直径和Poisson比表达的劈裂应变(水平向直径平面内的总应变)位移解,探讨了位移解的合理性,并与弯曲拉伸应变进行试验对比。研究表明:由于水平向直径平面内三向应力不为0,劈裂应变随Poisson比递减;圆盘直径越大,劈裂应变越小;竖向压缩使沥青混合料的劈裂极限应变远大于其弯拉极限应变。相较现有计算方法,文中推导的劈裂应变变化规律更符合实际情况。

Brazilian disk test(splitting test)only had the stress solution of the plane problem,and its strain could only be obtained from the constitutive equation,but the value of modulus must had a greater impact on the strain.In response to this problem,assuming that the specimen was elliptical during the splitting process,an displacement solution for the splitting strain(total strain in the horizontal diameter plane)expressed by vertical displacement,specimen diameter,and Poisson's ratio was derived based on geometric relationships.The rationality of displacement solutions was discussed and compared experimentally with bending tensile strain.Research showed that due to the non zero three-dimensional stress in the horizontal diameter plane,the splitting strain decreased with Poisson's ratio;The larger the diameter of the disc,the smaller the splitting strain;Vertical compression caused the splitting ultimate strain of asphalt mixture to be much greater than its bending tensile ultimate strain.Compared to existing calculation methods,the variation law of splitting strain derived in this article was more in line with the actual situation.