用非连续介质力学模型研究混凝土的Ⅰ型断裂

为进行连续介质到非连续介质转化的数值模拟,实现结构破坏过程的仿真分析,将固定和旋转的弥散裂缝模型与变形体离散元方法结合应用于混凝土、岩石等准脆性材料的受拉开裂过程分析。通过对比三点弯梁试验的数值模拟结果与试验结果,验证了模型能够定量预测裂缝的发生及开裂过程中的变形,获得了合理的结构荷载位移响应曲线,同时旋转裂缝模型同固定裂缝模型相比可以一定程度上避免剪切锁死现象。方法为连续非连续介质统一力学模型的进一步研究奠定了一定的理论基础。

Mode Ⅰ-concrete fracture analysis using a discontinuous medium mechanics model

Numerical simulations of the transition from continuous to discontinuous media and of structural collapse are inherentally difficult.Fixed and rotating smeared-crack models based on a deformable distinct element method were developed to analyze the fracture of quasi-brittle materials such as concrete and rock under tension.The model was compared with data from a three-point bending beam test.The model quantitatively predicts the initiation of fracture and the fracture process associated with the deformation.The load-displacement curves for the beam agree with the experimental data.The rotating crack model partially avoids the shear lock phenomena that occurs with the fixed crack model.The method lays a theoretical foundation for further research on mechanical models of continuous-discontinuous media.