基于回归分析法的改进Duncan-Chang模型研究

改进了Duncan-Chang模型的切线模量,并证明改进模型能克服传统模型应力应变曲线的数学缺陷。在获得多组三轴试验参数的基础上,利用Matlab中的lsqcurvefit函数对Duncan-Chang切线模量和改进切线模量进行回归分析。结果表明:改进切线模量的残差平方和比Duncan-Chang模型切线模量的残差平方和小,因而改进模型能更好地模拟实际情况;试验参数取平均值时改进切线模量的残差平方和比其利用回归分析所得的残差平方和大,说明利用回归分析法拟合试验参数是一种很好的途径,其结果更符合材料客观平均状态。

Use Regression Analysis to Study the Improved Duncan-Chang Model

The tangent modulus of Duncan-Chang was improved.The improved model was proved to be able to overcome the mathematic defects of stress-strain curve from the traditional model.Regression analysis of the Duncan-Chang modules and the improved tangent modulus were carried out using the lsqcurvefit function of Matlab based on triaxial test parameters.The results show that: the residual sum of squares of improved tangent modulus is smaller than that of the Duncan-Chang model,which makes the improved tangent modulus better on simulating the real situation.For the improved tangent modulus,the residual sum of squares based on the average test parameters is bigger than that based on test parameters obtained by the regression analysis.So it is a good approach to use the regression analysis to fit test parameters,as the result agrees better with the normal state of the material.