Article
Engineering, Mechanical
Lena Leicht, Tomas Fila, Petr Maca, Manfred Curbach
Summary: This paper presents an innovative technique for measuring the bond stress-slip relationships during dynamic pull-out using a tensile split Hopkinson bar and a near-to-full-scale beam-end specimen. The complex wave propagation behavior during impact is characterized and two methods for separating the longitudinal stress waves are employed. The method is considered suitable for evaluating the dynamic bond stress-slip relationship.
INTERNATIONAL JOURNAL OF IMPACT ENGINEERING
(2023)
Article
Engineering, Mechanical
Sudheer Prabhu, Tong Qiu
Summary: The discrete element method has been used to study the micro-mechanical behavior of sand with upscaled particle size distribution in order to reduce computational cost, but the impact of particle breakage at high stresses on dynamic sand response is still not well understood. Results show that well-calibrated parameters can provide similar dynamic stress-strain response with upscaled PSD specimens, emphasizing the importance of considering particle breakage in stress-strain response under high stresses.
INTERNATIONAL JOURNAL OF IMPACT ENGINEERING
(2021)
Article
Construction & Building Technology
Xing Chen, Changzhong Wang, Suwen Chen, Siyi Yi, Yong Lu
Summary: Low-iron ultra-clear float glass (LIFG) has become popular in landmark and large-scale buildings for its aesthetic characteristics. This paper investigates the dynamic mechanical properties of LIFG for blast resistance design by conducting quasi-static and dynamic tests. The results show that the dynamic compressive and tensile strengths of LIFG are strain-rate dependent, with the tensile strength being more sensitive to strain rate. The strain rate effect does not significantly affect the Young's modulus of LIFG.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
Baofeng Huang, Xiangfei Zhang, Xiaofeng Ma
Summary: The uniaxial compression behavior of building sandstone at high strain rates is investigated using dynamic and static compression tests. It is found that the static compression strength of flattened cylinders is 50% higher than that of standard cylinders. The study also explores the relationship between strain rate and fracture damage, and analyzes the correlations between dynamic strength, strain rate, and dynamic modulus based on experimental results.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Geosciences, Multidisciplinary
Zhoujie Gu, Rongxi Shen, Zhentang Liu, Enlai Zhao, Hailiang Chen, Zichen Yuan, Xiaomeng Chu, Jiawei Tian
Summary: Dynamic failure experiments were conducted on coal samples under dynamic load in a triaxial Split-Hopkinson pressure bar test system to study the dynamic characteristics of coal in a multi-axial pre-stress state. The experiments showed that the 3D pre-stress state significantly affects the dynamic failure of coal. The dynamic initial stress of coal increases linearly with strain, then grows at a reduced rate until the peak strength, and the mechanical curve rebounds notably. The dynamic strength factors of coal vary significantly with the increase of confining pressure.
NATURAL RESOURCES RESEARCH
(2023)
Article
Chemistry, Physical
Shumeng Pang, Weijun Tao, Yingjing Liang, Shi Huan, Yijie Liu, Jiangping Chen
Summary: A true biaxial split Hopkinson pressure bar device was developed to achieve biaxial synchronous impact loading of a specimen. The symmetrical wedge-shaped, dual-wave bar is designed to decompose a single stress wave into two independent and symmetric stress waves that eventually form an orthogonal system and load the specimen synchronously. This novel technique shows promise for material mechanics testing.
Article
Mechanics
S. Pant, S. Tamboli, S. N. Khaderi
Summary: This study investigates the distortion of incident signals in Split-Hopkinson bar experiments when using threaded collars to connect the anvil/collar and the incident bar. Finite element method is employed to analyze the effect of pitch and backlash between the mating threads on the incident wave. The results show that backlash leads to significant signal distortion, while the pitch has no influence. A one-dimensional analytical model is developed based on insights from the finite element analysis and is validated against experiments.
JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME
(2022)
Article
Engineering, Geological
Jin Huang, Xiaoli Liu, Danqing Song, Jian Zhao, Enzhi Wang, Jianmin Zhang
Summary: An auxiliary device for simulating the liquid-filled layer was developed to analyze the dynamic response characteristics of liquid-filled rock joints in the laboratory. The experimental results showed that the energy propagation coefficient and peak liquid pressure decreased with increasing joint inclination within the considered range, and smaller coefficient values were obtained for granite specimens compared with PMMA specimens. The peak pressure for granite specimens was slightly higher than that for PMMA specimens.
JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING
(2022)
Article
Engineering, Multidisciplinary
Xiaoyuan Sun, Tingxu Jin, Jihui Li, Jianlin Xie, Chuantian Li, Xiaoxia Li
Summary: This paper comprehensively explores the dynamic mechanical properties and crack evolution characteristics of coal and rock during impact failure. Experimental specimens from the same area are prepared to highlight the correlations between test pieces. The evolution laws of surface cracks and the distribution characteristics of sample fragments are studied, and simulation results are compared with experimental results.
MEASUREMENT SCIENCE AND TECHNOLOGY
(2023)
Article
Geochemistry & Geophysics
Qirui Wang, Qihu Zhang, Liyun Yang, Fuli Kong, Chenxi Ding, Junqi Fan
Summary: Experimental research was conducted on intact rock mass and jointed rock mass using numerical software LS-DYNA and indoor SHPB impact system to study the effects of confining pressure and joint material properties on stress evolution and fracture behavior. The study obtained the peak stress, reflection and transmission coefficient, and specimen failure state under different schemes. The research explained the propagation and attenuation law of explosive stress waves, considering the effects of confining pressure level and joint material properties. The results showed that the impact resistance of limestone specimen can be increased within a specific range of confining pressure, but it decreases if the confining pressure continues to increase after reaching the peak value. The dynamic strength of jointed rock mass and the impact damage resistance followed the same pattern, depending on the type of joint material.
Article
Engineering, Multidisciplinary
Yao-ke Wen, Liang Xu, Ai -jun Chen, Fang-dong Dong, Bin Qin
Summary: The dynamic compressive response of porcine muscle was investigated using a modified Split Hopkinson Pressure Bar (SHPB) in order to accurately measure the soft tissue. A circular cardboard disk pulse shaper was applied to generate a suitable incident pulse, and Polyvinylidene fluor (PVDF) transducers were used to measure forces and calculate stress. The results showed that the stress-strain curves are sensitive to strain rate and the compressive stress perpendicular to the fiber direction is stiffer. Additionally, a strain rate-dependent constitutive model was developed to describe the muscle's dynamic mechanical properties.
DEFENCE TECHNOLOGY
(2023)
Article
Engineering, Geological
Cong Zhang, Zhende Zhu, Shanyong Wang, Yonggang Zhang
Summary: The behavior and change laws of rock mass under dynamic loads were investigated in this study. The peak strength of rock samples showed a power function relationship with strain rate. The presence of a cemented interface attenuated stress waves and energy dissipation, and inhibited further crack development.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Mining & Mineral Processing
Zhenyu Han, Diyuan Li, Xibing Li
Summary: Filled inclusions in rock discontinuities have a significant impact on the mechanical characteristics and stability of rock engineering. Experimental results show that the interlayer strength influences wave propagation and fracture processes. Increasing interlayer stiffness leads to higher transmission coefficient, strength, closure, and stiffness. The cement mortar layer acts as a buffer, while a weaker interlayer causes slabbing near the rock-mortar interface.
INTERNATIONAL JOURNAL OF MINING SCIENCE AND TECHNOLOGY
(2022)
Article
Construction & Building Technology
Zhijie Huang, Wensu Chen, Hong Hao, Roland Aurelio, Zhixing Li, Thong M. Pham
Summary: This study investigates the dynamic compressive and splitting tensile properties of ambient-cured geopolymer concrete (GPC) using split Hopkinson pressure bar (SHPB). The results show that ambient-cured GPC exhibits strain rate sensitivity, with the dynamic increase factor (DIF) increasing with strain rate. The specific energy absorption of ambient-cured GPC under dynamic compression increases linearly with strain rate.
JOURNAL OF MATERIALS IN CIVIL ENGINEERING
(2022)
Article
Chemistry, Physical
Albin Wessling, Jorgen Kajberg
Summary: This paper presents a detailed study on the dynamic mechanical characterization of two rock materials (Kuru grey granite and Kuru black diorite) using a Split-Hopkinson Pressure Bar and high-speed imaging. The study provides information about the fracture initiation and propagation, as well as the indirect tensile strain and strain rates on the surface of the materials. The results show that a proper selection of the sensing region and high temporal resolution can reliably estimate crack formation and subsequent propagation.
Article
Engineering, Geological
Guowei Ma, Chen Huang, Junfei Zhang
Summary: In this study, a 3D printed underground tunnel model was fabricated to simulate its failure mode, and piezoelectric transducers were embedded in the surrounding rock for monitoring and evaluation. The results showed that as the load increased, cracks appeared above the tunnel roof and below the floor, and then coalesced into the tunnel boundary, ultimately leading to the model's failure. This research is significant for damage identification and residual strength estimation of other 3D printed structures in civil engineering.
JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING
(2023)
Article
Construction & Building Technology
Huidong Wang, Fengfeng Song, Yun Chen, Tuo Li, Guowei Ma
Summary: The extended key block theory proposed in this study considers the forces between blocks and block rotation, which improves the accuracy and efficiency of analyzing the stability of fractured rock masses. By incorporating a displacement constraint method and analyzing block rotatability, the extended method provides more accurate forces between blocks and considers the influence of block rotation on stability.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2023)
Article
Engineering, Geological
Xuefei Wang, Chi Cheng, Jianmin Zhang, Guowei Ma, Jiale Li, Jinzhao Jin
Summary: The quality control of subgrade compaction depends on post-evaluations. The potential bias is caused by the limited coverage of spot tests at the construction site. Intelligent compaction is developed by integrating the sensing system on the vibratory roller and used at the construction site of the Rongwu highway to monitor the compaction quality in real time. The compaction meter value (CMV) is recorded for three months. The sand cone tests are performed following the roller passes. The CMV is proven to be proportional to the roller pass, and it is feasible to represent the compactness of subgrade soils. The linear regression model is developed based on the in situ measured compactness first. An artificial neural network (ANN) model is proposed to correlate the CMV and the compactness by considering the influences of soil properties and control parameters. The prediction model demonstrates good correlations. This study aims to establish a reliable model to improve the feasibility of IC, filling the gap between the continuously recorded CMV and the compactness. This model is to be integrated into the IC system for real-time assessing the compaction quality of subgrade.
Article
Construction & Building Technology
Guowei Ma, Tingyu Hu, Fang Wang, Xiongfei Liu, Zhijian Li
Summary: This paper develops a systematic approach to evaluate and optimize the printability and printing quality of powder-based 3D magnesium phosphate cement (MPC) printing. The results show that mapping the proportions of ingredients and using specific modulators can improve printing accuracy and surface quality. The addition of 1,2-propylene glycol and Surfynol 465 to the binder, and quartz sand to the powder bed, significantly enhances the viscosity, reduces surface tension, and improves spreadability and surface flatness. The use of appropriate content of polyvinyl alcohol (PVA) controls the penetration and diffusion of the binder, leading to improved printing accuracy and reduced porosity.
CEMENT & CONCRETE COMPOSITES
(2023)
Article
Construction & Building Technology
Yushi Liu, Weichen Tian, Guowei Ma
Summary: In this study, electric activation (EA) curing was used to rapidly manufacture on-site reinforced concrete (RC) beams in severely-cold environment. The results showed that EA cured beams maintained a stable increasing trend in electrical resistance during the entire curing process, and the temperature field inside the structure remained uniform at around 45 degrees Celsius. Mechanical property tests demonstrated that EA curing could rapidly enhance the strength of RC beams under severely-cold conditions, reaching a compressive strength of 28.4 MPa, equivalent to C30 concrete grade. Furthermore, the structural performance of EA manufactured RC beams was found to be superior to beams manufactured through standard curing methods. This research provides a comprehensive investigation into the performance development of RC beams subjected to EA curing in extremely-harsh environments, facilitating the rapid fabrication of high-quality concrete structures in cold regions.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
Yang Liu, Zhihua Liu, Hui Rong, Guowei Ma
Summary: This paper investigates the effect of stirring and foaming of culture medium solution and microbial solution under the same incubation conditions, as well as the factors affecting microbial foaming. It also explores the mechanical properties of foam concrete prepared by different preparation processes using a microbial foaming agent. The results show that the foaming nature of microbial foaming agents is the result of the synergistic effect of microorganisms, nutrients, and microbial metabolites. The foam concrete prepared by the prefabricated foam method exhibits better performance compared to the direct mixing method, meeting industry standards and having a uniform pore size distribution.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Green & Sustainable Science & Technology
Guowei Ma, Yun Chen, Wei Dong, Man Xu, Tuo Li, Huidong Wang
Summary: This study develops a unified pipe-network method to investigate the mechanism of nuclide migration in rough-walled fractures with filling properties. Analytical results are used to verify the numerical reliability of the model. A case study is conducted at the Xinchang (Beishan) site to investigate the migration process of U-238 in a fracture-network system. A safety classifier based on numerical results is developed to effectively evaluate the avoidance distance between the repository and the water-conducting zone.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Green & Sustainable Science & Technology
Ruo-Chen Zhang, Li Wang, Xuan Xue, Guo-Wei Ma
Summary: Three-dimensional concrete printing (3DCP) is an advantageous construction method in harsh environments, such as deserts. This study conducted a life cycle assessment to determine the environmental impact profile of 3DCP in desert areas. The comparison results show that 3DCP is more sustainable with lower environmental impacts compared to conventional construction methods.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Green & Sustainable Science & Technology
Qiaoyan Li, Guowei Ma, Yulin Lu
Summary: This study investigates the friction performance and compression properties of geotextile bags under different degrees of consolidation using the slope sliding test, direct shear test, and unconfined compression test. The geotextile bags consist of geotextile and tailings sands from a prototype tailings dam in Yunnan Province. The friction coefficients between the bags are obtained through the slope sliding test, while the direct shear test examines the ability of the bags to withstand vertical load. The unconfined compression test reveals that the ultimate bearing capacity of the geotextile bags remains the same under slow loading conditions despite different moisture contents before the test. Additionally, a stability analysis method based on the limit equilibrium theory is developed to assess the improved stability of the tailings dam using geotextile bags (TDGB) compared to a general tailings dam.
Article
Engineering, Manufacturing
Qian Wan, Wenwei Yang, Li Wang, Guowei Ma
Summary: 3D concrete printing is a promising construction technology for freeform civil structures. This study proposes an adaptive path-planning method based on medial-axis decomposition and transfinite mapping for multi-branched regions. The proposed method can eliminate discontinuity, minimize sharp turns, and avoid defects in solid filling, and support various types of grid generation with desired global continuity.
ADDITIVE MANUFACTURING
(2023)
Article
Engineering, Manufacturing
Li Wang, Kehan Ye, Qian Wan, Zhijian Li, Guowei Ma
Summary: In order to improve the adaptability of 3D concrete printing to freeform and topologically optimized pre-fabricated structures, inclined 3D printing for overhang structures is developed. The study establishes prediction criteria for stable buildability of additive stacking to facilitate inclined 3D printing. The approach of compounding retarder and accelerator simultaneously is adopted to optimize the working performance of 3D printed concrete materials.
ADDITIVE MANUFACTURING
(2023)
Article
Construction & Building Technology
Yimiao Huang, Zehui Huo, Guowei Ma, Lei Zhang, Fang Wang, Junfei Zhang
Summary: This study developed a multi-objective optimization (MOO) model combining the tree-based ensemble learning algorithm and non-dominated sorting genetic algorithm (NSGA-II) to solve the optimization problem of fly ash-slag based geopolymers. The MOO model was trained on a database collected from published literature with 676 mixture proportions. The UCS of fly ash-slag based geopolymers were modeled using different regressors, with the gradient boosted regressor showing the highest prediction accuracy (R = 0.966, RMSE = 5.295 MPa).
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Engineering, Civil
Wenwei Yang, Li Wang, Guowei Ma, Peng Feng
Summary: This paper presents an integrated design method for 3D concrete printing by incorporating extrusion-based manufacturing characteristics into the topology optimization algorithm. The method considers manufacturing constraints such as nozzle size and path continuity, as well as material and design constraints to achieve desired mechanical performance and lightweight designs. It also incorporates controls for closed regions and overhang angle to ensure global path continuity and stable stacking of printed structures.
ENGINEERING STRUCTURES
(2023)
Article
Engineering, Mechanical
Hongyuan Zhou, Jiale Fan, Xiaojuan Wang, Guowei Ma, Shangjiang Yu, Yonghui Wang
Summary: In this study, a sacrificial cladding with foam concrete filled aluminum tube as the core is proposed for structural protection against blast load. The energy absorption capacity of the cladding is experimentally investigated through quasi-static compressive test and blast test. Numerical investigations are also conducted to analyze the effect of foam concrete density, aluminum tube thickness, and tube spacing on the cladding's protective performance. The results show that foam concrete density and tube squeezing significantly influence the energy absorption capacity, and increasing foam concrete density improves the protective performance. Increasing foam concrete density and aluminum tube thickness, and reducing tube spacing can effectively reduce the energy input to the system.
INTERNATIONAL JOURNAL OF IMPACT ENGINEERING
(2023)
Article
Construction & Building Technology
Yushi Liu, Weichen Tian, Minjie Jia, Ling Wang, Guowei Ma
Summary: This study verifies the feasibility of electric activation (EA) curing method in manufacturing reinforced concrete beams under negative temperature, and clarifies the effects of stirrup on electrical and heating performances. The experimental results show that more stirrups can increase the curing temperature and heating rate, and the proper stirrup arrangement form is beneficial for the performance of the beams.
JOURNAL OF BUILDING ENGINEERING
(2023)
