Evaluation of failure mechanism and size effect of confined concrete under axial compression using mesoscopic mechanical modeling

建立了单轴压缩约束混凝土破坏机理的刚体-弹簧-有限元耦合模型。在本文提出的模型中，RBSM采用细观尺度本构模型，钢筋侧约束材料采用一系列梁和壳单元来模拟。通过与经验公式或试验结果的比较，验证了所建模型能够合理地评价承压混凝土试件的压缩响应。此外，利用所建立的模型对试件尺寸的影响进行了参数化研究，探讨了尺寸依赖的机理。

A coupled RBSM(Rigid-Body-Spring Model)-FEM model has been developed for evaluation of failure mechanism of confined concrete under uniaxial compression. In the proposed model, the RBSM is applied meso-scale constitutive models, and the steel reinforcing material for lateral confinement is modeled by a series of beam and shell elements. By comparing numerical results with the empirical formulas or the experimental results, it is confirmed that the proposed model can reasonably evaluate the compression response of confined concrete specimens. In addition, a parametric study of the influence of specimen size was conducted with the proposed model in order to discuss the mechanism of the size dependence.