Preliminary Study of Indentation Fracture Behavior by Using Two-Dimensional Distinct Element Method

• Main Authors: Hsiu-hua Chang, 張琇華
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/p9rhpr

碩士 === 國立臺灣科技大學 === 營建工程系 === 95 === This research applied numerical analysis by using a discrete element code, PFC2D , to simulate the indentation tests of the cement mortarspecimens indented by a single blade to investigate the evolution of crackdevelopment. Laboratory results of indentation tests with measurementsof acoustic emission were compared with the numerical results. It isshown that the numerical method could simulate quite well thedistribution of shear cracks and the propagation of tensile cracks.According to the preliminary parametric study, the ratio of maximumparticle size to minimum particle size would have better results when it is1.4. The loading speed has great influence on the simulation results,lowering the loading speed would have much better results. When thecoefficient of friction is 1.0, there is more prominent distribution of shearcracks. Parallel-bond model was used in this research to define the way ofbonding between particle contacts. The influence of the ratio between thetensile strength and the shear strength of the bonds on the simulation wasstudied. For smaller ratio of tensile/shear strength, the number of shearcracks would be smaller and the tensile cracks would propagatedownwards vertically. For larger ratio of tensile/shear strength, thenumber of shear cracks would be larger and the tensile cracks wouldpropagate downwards with higher angle of deviation from the center line.