基于三次样条插值法的光弹性巴西劈裂试验

Photoelastic Brazilian Splitting Test Based on Cubic Spline Interpolation

巴西劈裂试验过程中,应力场的变化规律难以准确分析。光弹性实验可以直观地反映出应力场的实时变化规律。通过光弹实验模拟巴西劈裂试验的过程,依据等差线图像可分析出应力的变化规律。采用三次样条插值法来获取等差值与等倾度的全场数据,结合剪应力差法实现全场应力的自动化计算。同时,采用PFC3D对试验过程进行模拟,计算出岩石的抗拉强度为0.87 MPa,通过最大载荷公式验证其准确性。对比350 N压力下的光弹计算结果与数值模拟计算结果,两者的误差不超过3%。

It is difficult to accurately analyze the variation of stress field in Brazilian splitting test.Photoelasticity experiment can directly reflect the real-time variation of stress field.The process of Brazilian splitting test is simulated by photoelastic experiment,and the stress variation law can be analyzed according to the isochromatic image.The cubic spline interpolation method is used to obtain the full field data of the isoclinic angle and the isochromatic fringe order.Combined with the shear stress difference method,the automatic calculation of full-field stress is realized.At the same time,PFC2 D is used to simulate the test process,and the tensile strength of rock is calculated to be 0.87 MPa,through the maximum load formula to verify the accuracy of numerical calculation.By comparing the results of photoelastic calculation and numerical simulation under 350 N force,it is found that the error between them is less than 3%.