Article
Engineering, Mechanical
Shijie Xie, Zhenyu Han, Tao Zhou
Summary: A damage constitutive relationship is established based on the generalized equivalent strain principle and the initial tangent modulus to reflect the initial damage recovery. A Weibull distribution-based model is also established to represent the deformation after the compaction point. The combination of these two constitutive models yields a piecewise expression of the complete stress-strain curve of rocks under uniaxial compression.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Construction & Building Technology
Ze Xia, Qiangling Yao, Xuehua Li, Linli Yu, Changhao Shan, Yong Li, Yisong Hao
Summary: This study investigated the effect of carbon fiber-reinforced polymer (CFRP) jacketing on the mechanical properties, crack evolution, and energy dissipation mechanism of coal specimens. Experimental results showed that CFRP jackets had a significant influence on the core failure process of coal specimens, changing the crack classification mode and localization of acoustic emission events.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Engineering, Geological
Binwei Xia, Yang Li, Huarui Hu, Yafei Luo, Jiajun Peng
Summary: This study investigated the effects of fracture dip angle on sandstone mechanical properties, failure modes, energy characteristics, and damage progression. The results showed that the compressive strength and elastic modulus of sandstone exhibited an asymmetrical U-shaped change trend with increasing fracture angle. The failure mode was a mixed tension-shear failure. The acoustic emission signals and energy characteristics changed significantly as the sample approached failure, with an active-calm-reactive phase characteristic. Additionally, a coupling damage model considering macro cracks and micro defects was established, which agreed well with the experimental results.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Engineering, Mechanical
Dejian Li, Hao Qi, Chunxiao Li, Changqi Li
Summary: In order to investigate the effect of initial cracks on the mechanical characteristics of mudstone specimens under uniaxial compression, uniaxial compression tests were conducted on mudstone specimens treated at different temperatures. Numerical models were also created using the finite-discrete element method to simulate the laboratory tests. A piecewise damage model was established to analyze the damage evolution process. The results showed that the initial crack density significantly influenced the mechanical characteristics of the specimens, including the stress-strain response and the uniaxial compression strength.
ACTA MECHANICA SINICA
(2023)
Article
Geosciences, Multidisciplinary
Jian Yang, Kang Zhao, Yufeng Song, Qing Wang, Kangqi Zhao, Yongbo Ji
Summary: This study conducted uniaxial compression tests on low-strength molybdenum ores combined with acoustic emission technology to study the damage evolution laws and damage constitutive model. The results showed that the accumulative ringing count and accumulative energy significantly increased before the stress peak, indicating that the low-strength molybdenum ores were about to enter the failure stage. A modified damage constitutive model was proposed based on accumulative ringing counts, which could simulate the deformation process of the ores before the peak stress. These findings provide a reference for the stability evaluation and control of low-strength molybdenum mines.
NATURAL RESOURCES RESEARCH
(2022)
Article
Engineering, Geological
Zhi Zhao, Xiao-Ping Zhou, Jun-Wei Chen, Qi-Hu Qian
Summary: Understanding the spatial propagation of 3D cracks and their effects on the mechanical properties of rocks during the failure process is of great importance. This study used X-ray CT imaging and 3D reconstruction techniques to investigate the spatial propagations of 3D cracks in sandstone under uniaxial compression. The results identified five cracking stages and showed that the stress variations differed depending on the cracking direction.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Chemistry, Physical
De-Hang Liu, Yue Qin, Li Zhuo, Jian-Feng Liu, Zhao-Qiang Zheng, Jian-Liang Pei, Huai-Zhong Liu
Summary: The compaction behavior and damage evolution of porous cement mortar were studied through cyclic uniaxial compression tests. It was found that the secant modulus of the mortar increases with stress in the pre-peak deformation stage and the damage variable is defined based on the accumulated irreversible strain. An improved constitutive damage model was proposed and showed good agreement with experimental results, indicating its ability to predict the mechanical properties of porous cement mortar.
Article
Engineering, Geological
Fengqiang Gong, Peilei Zhang, Lei Xu
Summary: A method for characterizing damage in rocks is proposed in this study, which includes the compression energy dissipation coefficient to provide a more quantitative calculation of damage variables in brittle rocks. Additionally, a correction coefficient is introduced to modify the classical model and better describe the constitutive relation of rocks. Experimental results validate the accuracy of the proposed model, indicating its ability to accurately describe the compression and loading-unloading processes of rocks.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Engineering, Mechanical
Zenghui Zhao, Hao Liu, Qing Ma, Junlong Shang
Summary: This study conducted uniaxial compression tests on heterogeneous composite rock masses with non-penetrating cracks using discrete element numerical simulation experiments. The results revealed the stress-strain variation and acoustic emission characteristics of the rock masses. The research also investigated the instability, failure characteristics, and crack coalescence process of the rock masses, as well as the influence of crack numbers and positions on their mechanical behavior.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Chemistry, Physical
Gang Meng, Zhizhen Liu, Ping Cao, Ziyang Zhang, Zhi Fan, Hang Lin, Huijuan Deng
Summary: This study conducted compression tests to analyze the acoustic emission characteristics and damage model of yellow sandstone. It also proposed an initial damage model that better describes the initial damage characteristics of yellow sandstone materials. The results showed that the strength and elastic modulus of yellow sandstone depend on the loading rate.
Article
Construction & Building Technology
Weizhen Liu, Juntao Chen, Zhongping Guo, Hengze Yang, Wenwu Xie, Yandong Zhang
Summary: This study investigated the mechanical properties, damage evolution, elastic modulus, and peak strain of cemented coal gangue-fly ash backfill under different curing temperatures and curing ages. The results showed that the elastic modulus and peak strain increased with higher curing temperatures, and a piecewise damage constitutive model was found to be in good agreement with experimental results. Four damage stages were observed, with complete damage occurring in specimens cured at higher temperatures. The damage trend under uniaxial compression indicated a slow increase in damage value until complete failure occurred. This study lays a foundation for analyzing the stability of cemented coal gangue-fly ash backfill in a high geothermal environment.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Mathematics, Interdisciplinary Applications
Yafeng Li, Lei Wang, Hongfei Gao, Jing Zhang
Summary: An improved discrete element model (DEM) is developed in this study to understand the defect effect in ceramic cracking process. The model parameters are calibrated and the uniaxial compression of ceramics with different crack lengths and inclination angles are simulated. The results show that the predicted crack patterns are qualitatively in agreement with experimental observations. The study also reveals the influence of crack length and inclination angle on the mode of crack initiation and propagation.
COMPUTATIONAL PARTICLE MECHANICS
(2023)
Article
Green & Sustainable Science & Technology
Baolin Xiong, Jia Sun, Yunmeng Zhao, Zhuangzhuang Wang, Zhiyuan Wang, Bo Chen
Summary: This study used digital image correlation method and acoustic emission equipment to observe the crack growth process in composite rock strata. The results showed that the strain field dispersion can be quantified using the covariance matrix parameter V, and the crack types can be identified based on the growth rate of V.
Article
Construction & Building Technology
Yanlong Li, Hanyu Guo, Heng Zhou, Yang Li, Junhao Chen
Summary: This study investigates the damage evolution of concrete with different degrees of freeze-thaw (F-T) damage through F-T cycle and compression tests. The results show that the degree of F-T damage increases with the number of F-T cycles. During compression failure, the amplitude of acoustic emission (AE) exhibits a more significant and rapid increase, indicating a more brittle behavior of concrete after F-T damage. The damage constitutive model established in this study accurately reflects the damage evolution of concrete during the entire process of uniaxial compression after F-T cycles.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Chemistry, Physical
Xinming Chen, Haowen Zhang, Yuping Wu, Huazhe Jiao, Liuhua Yang, Qinting Wang, Wenxiang Zhang
Summary: This study investigates the effect of layering of filling body on its mechanical properties and failure modes through experiments and numerical simulations. The results show that the concentration of the filling body can enhance its compressive strength, while increasing the filling times weakens its strength. The study also finds that there is initial layered damage in the layered filling, and the overall damage shows a trend of fast initial growth followed by slower growth.