轻集料混凝土局部受压试验及动力本构分析

为探究轻集料混凝土单轴局部受压动力特性,采用试验机对轻集料混凝土单轴局部受压本构关系进行相关试验研究.考虑了5种不同加载应变率和4种不同加载面积,在位移控制下,得到轻集料混凝土单轴局部受压应力-应变曲线.根据应力-应变曲线特征点的峰值应力、峰值应变和弹性模量,分析不同加载应变率与加载面积对特征点的影响.同时根据混凝土黏弹塑性损伤本构模型,考虑不同加载应变率和加载面积的影响修正模型参数,并通过试验数据验证理论模型的合理性.研究结果表明:加载应变率和加载面积对轻集料混凝土应力-应变曲线影响明显;不同加载面积对轻集料混凝土弹性模量、峰值应力及峰值应变有较大影响;所提出的理论模型能够准确描述轻集料混凝土材料局部动力荷载作用下的应变率效应和非线性行为.

Experiment and dynamic constitutive analysis of lightweight aggregate concrete under local compression

To investigate the dynamic behavior of lightweight aggregate concrete under uniaxial compression, the displacement controlled uniaxial compression experiments were carried out together by considering five loading rates and four loading areas, and the stress-strain curves of lightweight aggregate concrete were obtained. The effects of loading rates and loading areas on the peak stress, peak strain and elastic modulus were analyzed and discussed. The constitutive model of viscoelastic and plastic damage of concrete was developed by correcting the model parameters, and the rationality of proposed model was verified through experimental data. Results show that loading rates and loading areas have a significant effect on stress-strain curves of the concrete. Loading areas exhibit greater effects on elastic modulus, peak stress and peak strain of the lightweight aggregate concrete. The proposed model can accurately describe the strain rate effect and nonlinear behavior of the lightweight aggregate concrete under dynamic loading.