基于损伤塑性模型的超高性能混凝土双肢墩数值模拟研究

Numerical Simulation of UHPC Double Pier Based on Damage Plastic Model

为了准确模拟和预测超高性能混凝土(UHPC)构件在外部作用下的的非线性力学行为,基于塑性损伤模型研究了超高性能混凝土CDP本构参数的取值方法,包括损伤因子和单轴应力-应变关系的确定,并分析了考虑材料损伤和不考虑材料损伤对模拟结果的影响.通过对超高强度混凝土墩进行单调加载试验,得到了试验墩的破坏形态、荷载-位移曲线和位移延性.并建立了数值模型,对试验结果进行了对比分析.结果表明:不考虑材料损伤的CDP模型计算得出的结构承载力与延性,和试验值相比有较大误差,并且荷载-位移曲线在峰值点后的发展趋势与试验结果相去甚远.然而考虑材料损伤演化下的CDP模型能够准确预测UHPC结构的力学性能,最终模拟结果与试验结果之间的误差可以控制在5%以内,运用该方法能够为对UHPC进行更准确的非线性有限元分析提供参考.

In order to accurately simulate and predict the nonlinear mechanical behavior of ultra-high performance concrete(UHPC)members under the external action,based on the plastic damage model,the method of determining the constitutive parameters of CDP for ultra-high performance concrete was studied,including the determination of damage factor and uniaxial stress-strain relationship,and the influence of considering material damage and not considering material damage on the simulation results was analyzed.Through the monotonic loading test of the super high strength concrete pier,the failure mode,load displacement curve and displacement ductility of the test pier were obtained.The numerical model was established and the experimental results were compared.The results show that the results of bearing capacity and ductility obtained by CDP model without considering material damage are quite different from the test values,and the development trend of load displacement curve after the peak point is quite different.However,CDP model considering material damage evolution can accurately predict the mechanical properties of UHPC structure,and the final simulation results can be controlled within 5%of the error.This method can provide reference for more accurate nonlinear finite element analysis of UHPC.