钢-混凝土混合结构振动台试验的弹塑性损伤分析

通过LS-DYNA程序，二次开发了钢材和混凝土单轴弹塑性损伤本构模型，其中钢材损伤模型采用混合强化准则，可考虑材料的Bauschinger效应；混凝土损伤模型定义了拉、压两个损伤指数，能较为准确地模拟混凝土单边效应、箍筋约束效应等。结合程序中基于显示算法的纤维单元，建立了结构整体数值分析模型，并通过一个缩尺比例为1∶4的3层钢-混凝土混合结构模型振动台试验，验证了数值分析模型的分析精度，数值模拟得到了模型结构的损伤发展过程。此外提出一种通过实测应变反演应变测试部位材料的应力和损伤发展的方法，研究表明，应变反演能充分利用应变测试数据，获得材料应力和损伤发展过程，并对结构的性能退化进行评估。

Elasto-plastic damage analysis of shaking table test results of steel-concrete composite structure

Through the secondary development of LS-DYNA program, the uniaxial elasto-plastic damage constitutive models of steel and concrete were developed respectively. The mixed-hardening criterion was used and the Bauschinger effect was considered in the steel damage model. Two damage indices were defined in the concrete damage model so that both the unilateral effect and the confinement effect of concrete can be accurately simulated. Combined with the explicit algorithm based fiber element model, the method of building integral structure model for numerical analysis was proposed. The precision of this method was validated by the shaking table test of a 1/4-scaled model of a 3-story steel-concrete composite structure. Then, the damage evolution process of the test structure model was reproduced using the proposed numerical analysis model. Furthermore, an inverse calculation method for obtaining the stress and damage evolution process at a local area of the structure from the strain data measured at the same location was developed. The results show that this inversion method fully uses the measured strain data to get the structural stress and damage evolution process, and can make more accurate estimate for the performance degeneration process of structures.