混凝土结构材料非线性本构参数识别算法研究

针对混凝土材料特性离散性较大、本构参数不确定性较强的问题,本研究提出了基于RSM-CMA的钢筋混凝土结构材料非线性本构参数的识别算法。首先,讨论分析了ABAQUS混凝土损伤塑性模型与规范提供的混凝土本构模型的统一方法,开发了混凝土材料子程序,获取了影响混凝土单轴应力-应变关系的敏感待识别参数,给出了损伤塑性模型屈服面函数与塑性势函数等非识别参数的建议取值。其次,基于响应面法(RSM),实现了结构宏观响应与细观本构参数间隐性关系的显式表达,基于带约束的最小二乘原理,构建目标函数,利用混沌猴群算法(CMA),实现本构参数的优化识别。最后,以钢筋混凝土拱构件的数值仿真为算例,验证了本研究所提算法的准确性。结果表明:抗压强度、峰值压应变是混凝土本构敏感性参数;抗压强度为影响结构极限承载力的最显著本构参数,弹性模量次之,峰值压应变影响最小;本研究所提算法能够较为准确地识别材料的本构参数,有助于获取精确的结构层次宏观响应,可为有限信息下材料本构参数的辨识、获取提供参考。

Research on Parameters Identification Algorithm for Concrete Nonlinearity Constitutive Model

In view of the large dispersion of concrete materials and the uncertainty of constitutive parameters, a nonlinear constitutive parameter identification method for reinforced concrete structures based on RSM-CMA was proposed. First, the uniform way between the concrete damage plasticity model with constitutive model provided by the specification was discussed, concrete material subroutine was developed, and the sensitive parameters influencing uniaxial stress-strain curve was obtained, the suggested values of parameters such as yield surface function and plastic potential function in the CDP were given. Secondly, the explicit expression of the implicit relation between the structural macro response and the mesoscopic constitutive parameters was realized on the basis of RSM, and the objective function constructed by the least square principle with constraints was realized by CMA. Finally, a numerical example of a reinforced concrete arch member was given to illustrate the accuracy of the proposed method. Result shows that compressive strength and peak compressive strain are the constitutive sensitivity parameters of concrete. The effects of constitutive parameter on the ultimate bearing capacity decreased in order of compressive strength, the modulus of elasticity and the peak compressive strain. The algorithm presented can accurately identify the constitutive parameters of the material, and is helpful for the accurate acquisition of the macro response at the structural level. It can provide a reference for the identification and acquisition of the constitutive parameters of materials under limited information.