疲劳载荷下钢管混凝土强度预测模型仿真分析

Strength of Concrete Filled Steel Tube under Fatigue Load Prediction Model Simulation Analysis

对疲劳载荷下钢管混凝土强度进行准确预测,可提高建筑用混凝土结构的安全性,改善建筑的质量。进行凝土强度预测时,应对钢管混凝土的位移延性进行准确分析,计算钢管混凝土最大载荷强度,采集疲劳载荷下钢管混凝土最强度预测样本进行训练完成预测,而传统方法通过获取钢管混凝土强度荷载-应变曲线,通过建立钢管超高强混凝土本构关系进行强度预测,不能计算位移延性和最大载荷强度,降低了预测的精度。提出一种改进延性破坏准则的疲劳载荷下钢管混凝土强度预测建模方法。上述方法先建立钢管混凝土圆柱的低周疲劳寿命拟合曲线模型,计算出钢管混凝土的位移延性,得出钢管混凝土最大载荷强度,采集疲劳载荷下钢管混凝土最强度预测样本,并组建BP网络模型组建钢管混凝土轴心受压强度承载力预测模型。仿真结果证明,强度计算值和本构关系预测结果与实测值吻合良好。

It can enhance building concrete structural safety and improve building quality to accurately predict concrete filled steel tube （CFST） strength under fatigue load.It needs to analyze CFST displacement ductility exactly and calculate CFST maximum load strength during predicting concrete strength.Traditional method predicts strength via obtaining CFST strength load-strain curve and building steel tube ultrahigh strength concrete constitutive relation,it cannot calculate displacement ductility and maximum load strength and reduces prediction accuracy.This paper proposes a modeling method of CFST strength prediction under modified ductility failure criterion fatigue load.Firstly,the CFST columnar low cycle fatigue life fitted curve model is built.Then the CFST displacement ductility is calculated,and its maximum load strength is obtained.Finally,the CFST maximum prediction sample is collected,and BP network is used to build axial compression strength bearing capacity prediction model.Simulation results show that prediction result of strength calculation and constitutive relation is identical with measured value.