受侧向约束混凝土的内时损伤本构模型

ENDOCHRONIC DAMAGE CONSTITUTIVE MODEL FOR CONFINED CONCRETE

受侧向约束混凝土结构由于其核心混凝土处于三向受压应力状态,其强度和变形能力有了很大的提高,因此在土木工程得到了广泛的应用。为了更好的描述这一结构形式的强度和变形特征,该文结合Valanis所提出的内时理论和Mazars的损伤理论,建立了一种全新的适用于侧向约束混凝土结构分析的内时损伤本构模型。该模型考虑弹塑性与损伤的耦合,用内时理论来描述混凝土的弹塑性特性,用各向同性损伤理论描述混凝土微裂缝扩展引起的刚度退化,通过与试验结果以及与其他模型的比较证实了模型的正确性和必要性。最后将该本构模型用于对常见的约束混凝土结构,如钢管混凝土和CFRP约束混凝土结构的应力-应变全过程分析中。

The confined concrete structures are frequently used in civil engineering structures since the confinement will improve the strength and the deformability of the core concrete. In order to describe the strength and deformation characteristics of the confined concrete, a new endochronic damage constitutive model suitable for the analysis of the confined concrete is proposed in terms of endochronic theory developed by Valanis with the damage theory initiated by Mazars. In this model, the elasto-plasticity of the core concrete is described by endochronic theory, and the behavior of stiffness degeneration and strain softening due to microcrack propagation is described by isotropic damage theory. The comparison of numerical and experimental results shows the model＇s validation and the comparison with other models can illustrate the model＇s improvements. Finally, two structural applications are also considered： columns confined with CFRP composites and steel are analyzed.