非均质混凝土破坏过程的细观数值试验

MESOSCOPIC NUMERICAL TESTS ON FAILURE PROCESS OF HETEROGENEOUS CONCRETE

结合细观单元的弹塑性各向异性损伤本构模型,建立了研究非均质混凝土破坏过程及其非线性力学行为的细观数值试验模型。该模型基于混凝土材料细观层次的结构特征,采用Weibull随机分布函数引入材料的非均匀性;同时,为反映加载边界条件如端部约束等的影响,采用Bathe提出的接触问题约束函数法处理不同物体之间的相互作用。运用该模型,对压缩和拉伸加载方式下混凝土的渐进性破坏过程进行了系统性的数值试验,其结果与他人的研究结果基本一致,从而验证了该模型的合理性。该模型为从细观层次研究复杂加载方式下混凝土的渐进破坏过程,进一步揭示混凝土的破坏机理及其非线性力学行为本质提供了一种新的数值试验手段。

A mesoscopic numerical model to study the progressive failure process and the nonlinear mechanical behavior of heterogeneous concrete is established in combination with an elastoplastic anisotropic damage constitutive for concrete mesoscopic element. The proposed model is based on the mesoscopic structure characteristic of concrete, in which the Weibull distribution function is adopted to introduce the material heterogeneity, and the constraint function method for contact problems proposed by Bathe in 1997 to treat with the interaction between different objects such as the end constraint between specimen and end platens. By using the established numerical model, numerical tests about the progressive failure process and the nonlinear mechanics behavior of concrete specimen under compression and tension loading are then serially carried out. The obtained numerical results are basically corresponding with those of other researchers, thus further verifying the validity of this proposed mesoscopic numerical model. The proposed numerical model provides a new method to study the progressive failure process and the nonlinear mechanical behavior of heterogeneous concrete under complex loading.