混合算法在04公桥规徐变系数曲线拟合中应用

采用混合算法将04公桥规附录F中给出的混凝土徐变系数幂函数表达式拟合为指数函数表达式,从而得到了徐变计算的递推式.即首先用遗传模拟退火算法对徐变系数曲线进行初步拟合,估计传统非线性迭代计算中参数的初值;再通过基于Levenberg-Marquardt法和Gauss-Newton法的非线性最小二乘法对徐变系数进行精确的拟合;最后通过结果分析确定了指数函数表达式的最终形式.混合算法解决了应用单一算法在拟合徐变系数曲线上的局限性,有着良好的通用性、鲁棒性和精度,拟合结果可直接应用于采用递推法计算混凝土徐变的有限元程序中.

Application of hybrid algorithm to fitting of creep coefficient curve introduced in China Standard of 2004 Highway PC Bridge

A hybrid algorithm is adopted to fit the creep coefficient power function introduced in China Standard of 2004 Highway PC Bridge appendix F into exponential function, from which the successive expression of the creep can be obtained. The curve of creep coefficient is firstly fitted by the genetic simulated annealing algorithm to estimate the initial data. And then, based on the Levenberg-Marquardt method and Gauss-Newton method, the curve is exactly fitted by the nonlinear least square method. Finally, the exponential function is determined by the result analysis. The hybrid algorithm avoids the limit of a single algorithm in the curve fitting of creep coefficient, which takes good characters of universality, robustness and precision. The curve fitting results can be directly applied to the concrete creep program of FEM by recursive method.