基于格构模型理论的单纤维拉拔试验建模及仿真

Establishment and Simulation of Single Fiber Pull-Out Test Based on Lattice Model Theory

水泥基材料的单纤维拉拔试验对测试仪器要求较高,试验操作难度大,很多实验室不具备测试能力。针对该问题,采用格构模型理论建立模型,基于分段步进式方法,对单纤维拔出过程进行数值仿真,得到纤维拉拔荷载-位移响应曲线。通过文献中的试验数据对模型进行验证,发现该模拟方法可以模拟单纤维拉拔过程及荷载-位移曲线。进一步,通过模型研究纤维方向、弹性模量和水泥-纤维界面黏结强度对于拉拔荷载-位移响应曲线的影响。模拟结果可用于研究不同边界条件下各种因素对试验结果的影响,计算工程水泥基复合材料单裂缝桥接关系,为高韧性工程水泥基材料设计提供参考。

The single fiber pull-out test of cement-based materials requires mechanical loading instruments with high precise,but the test operation is complicated,thus many laboratories do not have the ability to test.In order to slove this question,the discrete lattice model was adopted to simulate the pull-out process of single fiber from cementitious matrix using the stepwise method,and the fiber pull-out load-displacement response curve was obtained.The model was verified by the experimental data in the literature,and it is found that the simulation method can simulate the single fiber pull-out process and load-displacement curve.The influences of fiber direction,elastic modulus of fiber and interfacial bond strength on the pull-out load-displacement response curve were investigated using the model.The simulation results can be further used to study the influences of various factors on test results under different boundary conditions.The simulated results can be used to calculate the single-crack fiber bridging relationship of engineered cement-based composite,providing theoretical support for design of high toughness engineering cement-based composites.