Experimental study on the influence of different sampling methods on the stress-strain and strength characteristics of weathered and water rich sandstoneYang, Chaoshuai; Lei, Shengyou; Yue, Xijun; Zou, Chong
doi: 10.1088/1742-6596/2790/1/012002pmid: N/A
In order to explore the physical and mechanical properties of layered weathered sandstone in a water rich environment, the authors obtained layered sandstone from the tunnel excavation section. Firstly, the physical properties and chemical composition were tested, and then uniaxial tests were conducted on sandstone, in which the loading direction was divided into perpendicular to the specimen bedding, parallel to the specimen bedding, and at a 45 ° angle to the specimen bedding. The uniaxial test results show that the stress-strain curve of sandstone is strain softening type. The uniaxial compressive strength of sandstone is between 2.18 MPa and 28.123 MPa, the residual strength is between 0.122 MPa and 24.284 MPa, the elastic modulus is between 5.843 MPa and 49.45 MPa, the Poisson’s ratio is between 0.303 and 0.484, and the softening coefficient of rock is between 0.15 and 0.20. The uniaxial compressive strength of sandstone samples subjected to blasting disturbance is 38% of that without blasting disturbance, and the elastic modulus is 30% of that without blasting disturbance. The axial and radial strains of sandstone samples significantly increased after blasting disturbance. Blasting significantly reduces the uniaxial compressive strength and elastic modulus of the sample. The uniaxial strength of sandstone decreases exponentially with increasing water content.
Hydration characteristics and kinetic analysis of polyacrylamide (PAM) anti-dispersion cement-based materialsHe, Yang; Wei, Hua; Li, Chunhe; Lu, Hao; Xu, Fei; Zhang, Jiaming
doi: 10.1088/1742-6596/2790/1/012001pmid: N/A
Through phase analysis and quantitative calculations of the hydration process, the inclusion of polyacrylamide (PAM) in Anti-dispersion Water Paste affects its hydration characteristics is discovered. Specifically, the presence of PAM reduces early reactivity while accelerating progress in the middle to late stages of hydration. By employing K-D hydration kinetic analysis, it is confirmed that the use of PAM results in the formation of a multi-nucleation homogeneous point system within the cement slurry. This system prolongs the NG (nucleation and growth) process time, increases the hydration degree during the transition from NG to I (induction) process, and inhibits the heterogeneous precipitation of hydration products. Consequently, the early hydration of cement is hindered. As the hydration reaction advances, the microstructure of the product under multi-nucleation points increases the specific surface area. This gradual breakthrough of the hydration threshold barrier shortens the duration of the phase boundary reaction process and reduces the hydration degree during the I and D (diffusion) processes. Consequently, the late-stage hydration rate is accelerated.
Peer Review Statementdoi: 10.1088/1742-6596/2790/1/011002pmid: N/A
All papers published in this volume have been reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.• Type of peer review: Double Anonymous• Conference submission management system: Morressier• Number of submissions received: 28• Number of submissions sent for review: 21• Number of submissions accepted: 17• Acceptance Rate (Submissions Accepted / Submissions Received × 100): 60.7• Average number of reviews per paper: 2• Total number of reviewers involved: 34• Contact person for queries:Name: Emma LiEmail: [email protected]: Organizing Committee of MVE 2024
Dynamic analysis of a hydraulic motor lifting auxiliary beam of monorail craneLiu, Y L; Lu, J L; Chu, L L; Yu, C L
doi: 10.1088/1742-6596/2790/1/012008pmid: N/A
Monorail crane that is an important class of auxiliary transportation equipment in coal mine. It works on a single hanging track fixed above the coal mine roadway to transport materials, machines, people, etc. Lifting auxiliary beam is the main part of the lifting beam which is used to complete the lifting and transport operations. In the application process, the lifting auxiliary beam is bore many types of loads such as discontinuous loading, frequent starting and braking etc. It complicates the dynamic performance that directly affects the safety and the lifting operation stability. By using finite element method, a dynamic model of the lifting auxiliary beam is established to study the variation laws of dynamic load, frequency, amplitude, etc. Furthermore, three loading conditions are defined in the model. They are static loading, slow loading and fast loading, considering the lifting operation time. The numerical simulation results show that the maximum displacement of the fast loading condition is 20% to 23% higher than that under the static loading condition. Moreover, under the fast loading condition, the largest displacement amplitude occurs in the middle part of the lifting auxiliary beam and it decreases gradually towards the ends.
Nanosecond laser-assisted fabrication of Ti6Al4V surfaces with gradient wettability and robust cross-linked microstructuresChen, Jianli; Fan, Yaohua; Wan, Libo; Wu, Weifeng
doi: 10.1088/1742-6596/2790/1/012013pmid: N/A
Surfaces with gradient wettability outperform singular superhydrophobic surfaces in terms of self-cleaning efficiency, anti-contamination properties, and fluid manipulation. These attributes offer extensive application potential across various industrial and scientific domains. This study introduces and employs nanosecond pulsed laser ablation to create wettability gradient surfaces on Ti6Al4V alloys, featuring robust cross-linked frame microstructures. Experimental results demonstrate that by varying the ridge width (w), associated with the liquid-solid contact fraction, we can achieve varying wettability and mechanical durability in these cross-linked frame microstructures. Wettability tests indicate static contact angles ranging from 150.7° to 105.45°. Furthermore, the sandpaper linear abrasion test illustrates a decrease in material wear rate with an increase in w. Under similar test conditions, the proposed surfaces demonstrate superior mechanical durability compared to two other prevalent wettability surface structures. The proposed surfaces, efficiently and eco-friendly produced through nanosecond laser fabrication, hold tremendous potential for diverse applications.
Investigation of the mineralogical composition and origin analysis of black jadeiteGuo, Fenghui; Xu, Wei; Tang, Minghui; Zhang, Ziqi; Chen, Zean; Lu, Hao
doi: 10.1088/1742-6596/2790/1/012003pmid: N/A
Analyzing black jadeite variety is helpful not only to distinguish black jadeite from the common omphacite jadeite, but also to learn the origin of jadeite by studying these special specimens. The basic gemological properties, mineral composition, structural characteristics, spectroscopic features, and color-causing mechanisms of black jadeite were studied through testing methods such as Polarizing microscope, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy. Recent studies have confirmed the distinct crystalloblastic textures of black jadeite—namely columnar, granular, and fibrous—alongside its characteristic fracture structures. This research further identifies the presence of secondary minerals, primarily opaque black impurities consisting of a graphite and disordered graphite mixture, as revealed by Raman spectroscopy and X-ray diffraction analyses. These analyses have elucidated that the variable distribution of graphite mixtures contributes to differing degrees of light absorption, thereby forming various shades of black, a critical factor in the gemstone’s coloration. This study suggests that these carbonaceous materials are a byproduct of the carbonization of organic matter within metamorphic fluids, subsequently forming dispersed graphite structures within the mineral matrix and its fractures, indicative of multi-stage metamorphic processes. Additionally, the identification of graphite supports the theory that jadeite’s protolith originated from the subduction processes of the Neotethys Ocean, accompanied by metasomatism and high-pressure metamorphism of olivinite.
Study on heat dissipation of torsional vibration damper for engine crankshaftChen, Rongchuang; Qiu, Zexu; Wu, Changbin; Gan, Xingang
doi: 10.1088/1742-6596/2790/1/012009pmid: N/A
High temperatures in torsional vibration dampers can cause silicone oil to fail, increasing crankshaft vibration and shortening component fatigue life. Accurate prediction of the damper temperature field is key to the manufacture of highly reliable torsional vibration dampers. This study establishes the relationship between temperature, torsional vibration amplitude, silicone oil viscosity, rotational speed, housing and inertia ring clearance, and heat generation power based on Comsol. A bench test was carried out on a 6-cylinder inline diesel engine. The simulated temperature profile matched the tested result in terms of trend and relative value, and the established model could accurately predict the temperature field of the engine crankshaft torsional vibration damper.
Research on the optimal design of roadway support for fully mechanized coal seam working faceLiang, Qiuhui; Zhang, Baoliang
doi: 10.1088/1742-6596/2790/1/012004pmid: N/A
For the optimal design of surrounding rock deformation and support in the shallow buried coal seam of large-scale fully mechanized mining face, this paper took the surrounding rock of the roadway as the research object, used theoretical calculation and numerical simulation to establish the mechanical model of the deformation of the surrounding rock structure, and proposed and analyzed the reasonable roadway support scheme of the shallow buried coal seam. The numerical simulation results showed that the top anchor rod with Φ18×2200 mm and the inter-row distance of 1100×1000 mm, the anchor cable with Φ15.24×6300 mm and the inter-row spacing of 2200×2000 mm, the upper part anchor of Φ16×2200 mm, and the C30 concrete with a thickness of 200 mm for laying the bottom plate are selected, which was certified as the optimal support scheme. In practical engineering applications, the deformation of surrounding rock has been effectively controlled, and the supporting effect of surrounding rock was obvious, which was of great significance to ensure the safe production of coal mines.
Theoretical and experimental research of filtration efficiency and resistance of multi-fiber air-filter materialsYu, Yanzi; Zhang, Cheng; Zhang, Jiuzheng; Wu, Yaohua; Deng, Rui; Wu, Yu; Cai, Jinming
doi: 10.1088/1742-6596/2790/1/012006pmid: N/A
The filtration efficiency and resistance during the process of fluid flowing through filter materials is significantly influenced by the characteristic of filter materials, especially for air-filter materials which generally have a multi-fiber composite structure. Therefore, it is important to pay attention to the filtration efficiency and resistance of multi-fiber filter materials. In this study, theoretical equations of filtration efficiency and resistance were proposed based on uniform and multi-fiber composite filter materials, and series of experimental verifications had been implemented. The results indicated that the experimental results verified the theoretical equations well, which may accelerate the research and development of new air-filter materials.
Numerical method determining the time-dependent position of a minority phase sphere in the Fe-Cu alloy dropletLi, Mei; Peng, Yinli; Tian, Lili; Liu, Gang; Xie, Fang
doi: 10.1088/1742-6596/2790/1/012012pmid: N/A
A numerical method was developed to track the dynamic positions of the L2 phase sphere inside the Fe-Cu alloy droplet. Firstly, the temperature field distribution within alloy droplet was calculated, and the variation in thermal gradient was analyzed. Secondly, the migration behavior of the sphere was analyzed based on Marangoni convection. Finally, the theoretical position of the 10 μm sphere was determined. The results demonstrated that there is a little difference in temperature between the center and the surface of the droplet, but its gradient is very different. Moreover, the maximum migration times for the L2 phase sphere were determined to be ~0.02 s, 0.07 s, and 0.14 s within 300μm, 600μm, and 900μm alloy droplets, respectively. In addition, it was also found that the same-sized spheres can reach the same relative position, i.e., 0.485R. This means the final position of the sphere within the different alloy droplets is independent of the droplet size.