Investigating the effect of initial cracks on the mudstone mechanical behavior under uniaxial compression using FDEM

• Published in: Acta mechanica Sinica Vol. 39; no. 10
• Main Authors: Li, Dejian, Qi, Hao, Li, Chunxiao, Li, Changqi
• Format: Journal Article
• Language: English
• Published: Beijing The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of Sciences 01.10.2023; Springer Nature B.V
• Edition: English ed.
• Subjects: Classical and Continuum Physics; Compression tests; Compressive strength; Computational Intelligence; Cracking (fracturing); Cracks; Damage assessment; Density; Discrete element method; Engineering; Engineering Fluid Dynamics; Evolution; Laboratory tests; Mechanical properties; Modulus of elasticity; Mudstone; Nonlinearity; Numerical models; Research Paper; Stress-strain curves; Stress-strain relationships; Theoretical and Applied Mechanics; Uniaxial compression test; Damage model; Mudstone; Initial cracks; FDEM
• ISSN: 0567-7718; 1614-3116
• DOI: 10.1007/s10409-023-22421-x

For investigating the effect of the initial cracks on the mechanical characteristics of mudstone specimens under uniaxial compression, firstly, uniaxial compression tests on mudstone specimens treated by different temperatures (20 °C, 30 °C, 60 °C and 80 °C, respectively) were carried out. Then, some uniaxial compression numerical models containing the certain number of initial elliptical cracks were built using finite-discrete element method (FDEM) to simulate laboratory tests. Lastly, a piecewise damage model was established to reveal the damage evolution process. It is found that the modelling results present a well agreement with laboratory tests in the aspect of stress-strain response. The test and simulation results reveal that initial crack density has a significant influence on the uniaxial compression mechanical characteristics. Specifically, with the increasing initial crack density, the initial nonlinearity is more obvious, but the elastic modulus and uniaxial compression strength are in decrease. And the cracking event counts are in decrease as increasing the initial crack density while the open fracturing mode is more dominant. Furthermore, the piecewise damage model can reproduce the stress-strain curves finely. If the initial nonlinearity is obvious, it is feasible to divide the damage evolution process into initial damage, damage decrease, and damage increase stages.