混凝土抹裂纹模型动态分析的局限性Limitations of Smeared Crack Models for Dynamic Analysis of Concrete.pdf

12th International LS-DYNA® Users Conference Constitutive Modeling(3) Limitations of smeared crack models for dynamic analysis of concrete Yoeng Sin Khoe and Jaap Weerheijm TNO PO Box 4, 2280AA Rijswijk The Netherlands Summary Performance prediction of concrete structures under explosive loadings or impact is an essential part of the research that is being performed within TNO. One of the current research topics is the explosive safety of tunnel structures. In the context of this research we evaluate the capabilities and limitations of concrete material models in LS-DYNA. The evaluation focuses on the CSCM concrete model and in particular the damage and failure characteristics of the model under single and sequential compression and tensile loading. Like many existing concrete models, the CSCM uses a smeared crack approach to model the reduction in strength of damaged concrete. It will be shown that the smeared crack approach has an intrinsic limit that places a restriction on the minimum size of an element. Furthermore, it is predicted that the built-in fracture energy regularization further aggravates the situation. The regularization algorithm tries to maintain a constant fracture energy. When elements have a size that is smaller than the limit size, the fracture energy of the total structure is increased which causes non-physical behavior. The predictions are confirmed by analyses on a tunnel structure as well as analyses on concrete cylinders under tension and compression. In contrast to the established minimum width, high dynamic loads or very local