爆炸荷载作用下钢筋混凝土结构的动态响应与破坏模式的数值分析

NUMERICAL INVESTIGATION FOR DYNAMIC RESPONSE AND FAILURE MODES OF RC STRUCTURES DUE TO BLAST LOADING

在爆炸荷载(尤其是脉冲荷载)作用下,除了常见的弯曲破坏形态之外,钢筋混凝土结构还可能发生直剪破坏和弯剪破坏。如何准确地预测爆炸荷载作用下的钢筋混凝土结构动态响应和破坏特征是当前抗爆结构领域十分关注的课题之一。该文介绍作者近年来在这方面的一些研究成果,主要有:将三参数形式的应变速率型材料模型推广应用于二维状态下的混凝土本构关系,建立了弹粘塑性混凝土结构有限元分析方法;基于Timoshenko梁理论和弹粘塑性理论,分别采用有限差分法和有限元法,建立了土中浅埋钢筋混凝土结构动力响应和破坏模式的有限差分和有限元分析方法。对爆炸荷载作用下的典型钢筋混凝土结构计算结果表明:基于Timoshenko梁理论的有限差分分析方法和有限元分析方法能较好地模拟梁的动态响应和弯曲、弯剪以及直剪的破坏模式,而二维弹粘塑性混凝土结构有限元分析方法只能较好地模拟梁的弯曲破坏模式。

The flexure-shear and direct shear failure modes of RC structures due to blast loading are possibly observed experimentally apart from the frequently observed flexural failure mode. Much attention has been paid to this aspect, especially the exact prediction of the dynamic response and failure modes of RC structures due to blast loading. Some recent progress relevant to the following aspects is presented: (1) a 2D elasto-viscoplastic finite element method for concrete structures is developed by extending the proposed strain rate-sensitive material model to the constitutive relationship of concrete under two-dimensional state; (2) based on the theory of Timoshenko beam and theory of elasto-viscoplasticity, a finite element method and a finite differential method are proposed respectively to predict the dynamic response and failure modes of shallow-buried RC structures. It is demonstrated that the proposed 2D elasto-viscoplastic finite element method can predict the flexural failure modes of blast-loaded RC structures, and the proposed Timoshenko beam finite element method and finite differential method can determine the flexural, flexure-shear and direct shear failure modes of blast-loaded RC structures.