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为研究再生混凝土本构模型的特点及适用性,基于三种不同核心再生混凝土本构模型对钢管再生混凝土轴压短柱受力全过程进行非线性有限元分析,从极限承载力、轴压刚度、耗能因子等方面对数值模拟结果与93组试验数据进行对比分析.结果表明:在极限承载力方面,未考虑约束作用对峰值应力影响的本构模型计算结果偏安全;基于统一理论的本构模型计算结果对套箍系数较大的试件符合较好,而套箍系数较小时结果偏保守;考虑取代率、含钢率、钢材屈服强度对核心再生混凝土强度及弹性模量影响的约束再生混凝土本构模型,计算结果与试验结果符合程度较高.轴压刚度方面的分析表明,按照弹性叠加原理计算的构件轴压刚度相对于试验值偏低,而考虑再生混凝土取代率的组合轴压刚度计算方法及本构得到的计算刚度值与试验结果符合良好,另外两种本构的计算值偏于不安全.此外,三种本构模型计算的耗能因子均高于试验值,表现为模拟的荷载-位移下降段比试验曲线平缓.
In order to study the characteristics and applicability of recycled concrete constitutive model, nonlinear finite element analysis of the whole process of axial compression stub columns of recycled concrete filled steel tubular was carried out based on three different models of core recycled concrete constitutive model. The ultimate bearing capacity, axial compression stiffness , Energy dissipation factor and so on, the results of numerical simulation are compared with those of the 93 experimental data.The results show that in the ultimate bearing capacity, the constitutive model which does not consider the effect of restraint on the peak stress is biased, The calculated results of the model agree well with the specimens with large hoop coefficient, while the results are conservative when the hoop coefficient is small. The influence of the substitution rate, the steel ratio and the yield strength of the steel on the strength and elastic modulus of the core recycled concrete is considered The calculated results agree well with the experimental results.The analysis of axial compression stiffness shows that the axial compressive rigidity of members calculated according to the principle of elastic superposition is lower than that of the experimental values and that the composite shaft considering the replacement ratio of recycled concrete Compression stiffness calculation method and the constitutive calculated stiffness values are in good agreement with the experimental results. The other two constitutive calculations Further unsafe three constitutive model factor calculated energy values are higher than the test, expressed as a simulated load - displacement curve test gentler than the falling section.