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mechanical properties and supporting effect of CRLD bolts under static pull test conditions

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International Journal of Minerals,Metallurgy and Materials 2017年第1期24卷 1-9页

作者： Xiao-ming Sun Yong Zhang Dong Wang Jun Yang Hui-chen Xu Man-chao He State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyBeijingBeijing 100083China State Key Laboratory of Mining Disaster Prevention and Control Co-fotmded by Shandong Province and the Ministry of Science and Technology Shandong University of Science and TechnologyQingdao 266590China

A device for supporting soft rock masses combined with a constant resistance structure characterized by constant resistance and large deformation at the end of a steel bar, known as the constant resistance and large deformation（CRLD） bolt, has recently been developed to counteract soft rock swelling that often occurs during deep mining. In order to further study the mechanical properties of the CRLD bolt, we investigated its mechanical properties by comparison with the conventional strength bolt（rebar） using static pull tests on many aspects, including supporting capacity, elongation, radial deformation, and energy absorption. The tests verified that the mechanical defects of the rebar, which include the decrease of bolt diameter, reduction of supporting capacity, and emergence and evolution of fracture until failure during the whole pull process, were caused by the Poisson＇s ratio effect. Due to the special structure set on the CRLD bolt, the bolt presents a seemingly unusual phenomenon of the negative Poisson＇s ratio effect, i.e., the diameter of the constant resistance structure increases while under-pulling. It is the very effect that ensures the extraordinary mechanical properties, including high resistance, large elongation, and strong energy absorption. According to the comparison and analysis of numerical simulation and field test, we can conclude that the CRLD bolt works better than the rebar bolt.

关键词： deep mining bolts mechanical properties rock support static pull test

mechanical properties and simulated thermal conductivity of biomimetic structured PS-PVD(Gd_(0.9)Yb_(0.1))_(2)Zr_(2)O_(7) thermal barrier coatings

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Journal of Materials Science & Technology 2024年第15期182卷 33-40页

作者： Yiqian Guo Lei Guo Keyi Liu Shiyi Qiu Hongbo Guo Huibin Xu School of Materials Science and Engineering Beihang UniversityBeijing 100191China School of Materials Science and Engineering Tianjin UniversityTianjin 300072China Chinese Aeronautical Establishment Beijing 100012China Tianmushan Laboratory Yuhang DistrictHangzhou 311115China Research Institute for Frontier Science Beihang UniversityBeijing 100191China

Plasma spray physical vapor deposition(PS-PVD)(Gd_(0.9)Yb_(0.1))_(2)Zr_(2)O_(7)(GYbZ)thermal barrier coatings(TBCs)exhibited better silicate-phobicity than coatings produced by electron beam physical vapor *** combination with PS-PVD and ultrafast laser direct writing technology,biomimetic structured GYbZ TBCs,with a triple-scale micro/nano surface microstructure,were *** ablating on the PS-PVD GYbZ coating enhanced the surface roughness,improving its wear resistance without increasing the surface ***,during the laser ablation processing,numerous nanoparticles were deposited in-situ in the gaps between columns of the coating,reducing the coating Young’s *** simulated temperature field and heat flux field demonstrated that the presence of numerous interfaces between small columns of the PS-PVD coatings is beneficial to thermal ***,laser ablation decreased the coating thickness,reducing the thermal insulation by around 20%-30%as compared to its PS-PVD counterpart,suggesting that a moderate increase in the coating thickness should be considered when designing an efficient TBC system.

关键词： Thermal barrier coatings(TBCs) Plasma spray physical vapor deposition (PS-PVD) Laser ablation Biomimetic structure mechanical properties Thermal insulation

mechanical properties of frozen rock mass with two diagonal intersected fractures

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International Journal of Mining Science and Technology 2018年第4期28卷 626-633页

作者： Hao Yang Renliang Shan Jinxun Zhang Fumei Wu Zhiming Guo School of Mechanics and Civil Engineering China University of Mining & Technology Postdoctoral Workstation Beijing Urban Construction Group CO. Ltd.

Based on previous research results, this paper investigated the influence of fracture morphology on mechanical properties and failure modes of rock mass with two diagonal intersected fractures. This study carried out a series of triaxial compression tests on rock-like specimens with two crossed fractures under negative temperature, concluded the following conclusions. The strength and failure modes of rock mass are significantly influenced by the dips of two crossed fractures. The strength of rock mass with two frac- tures cannot simply be estimated using the method that was developed for the rock mass with a single fracture. When the intersecting angle is less than 30~, the failure plane initiates at the tip of ＂artificial rup- tures＂ and extends to the upper and lower ends of the specimen. In case of a higher dip and intersecting angle ranging from 30° to 60°, the failure plane propagates along one of these two fractures. The mechan- lca! parameters of rock mass are not only related to the trace length, but also depend on the trace !ength ratio. One could roughly calculate the strength parameters using the approximation proposed *** paper..For the rock mass with a trace length ratio 〈0.3 （short trace length/long trace length）, the failure mode is dependent on the fracture with a longer trace length. When the trace length becomes significant and the trace length ratio approximates to 1, the failure plane propagates along two fractures, where an *** pattern is presented： For the rock mass with moderate frac!ures and a trace length ratio of approxlmately 1, the failure mode *** on fractures, which is simllar to .the damage pattern of intact rock. The strength, and elastic .modulus of rock mass decrease with the increase of spacing between fractures, whl!e Polsson＇s ratio is Independent on the spacing. The failure mode can be deter- mined by the area. of triangle created by two fractures. Damage occurs at the smaller triangle area first, an

关键词： Intersected fractures Fracture morphology Failure modes mechanical properties

mechanical properties and interfacial characteristics of 6061 Al alloy plates fabricated by hot-roll bonding

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1890-1899页

作者： Zongan Luo Xin Zhang Zhaosong Liu Hongyu Zhou Mingkun Wang Guangming Xie State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China

This work aims to investigate the mechanical properties and interfacial characteristics of 6061 Al alloy plates fabricated by hotroll bonding(HRB)based on friction stir *** results showed that ultimate tensile strength and total elongation of the hot-rolled and aged joints increased with the packaging vacuum,and the tensile specimens fractured at the matrix after exceeding 1 ***-equilibrium grain boundaries were formed at the hot-rolled interface,and a large amount of Mg_(2)Si particles were linearly precipitated along the interfacial grain boundaries(IGBs).During subsequent heat treatment,Mg_(2)Si particles dissolved back into the matrix,and Al_(2)O_(3) film remaining at the interface eventually evolved into *** addition,the local IGBs underwent staged elimination during HRB,which facilitated the interface healing due to the fusion of grains at the *** process was achieved by the dissociation,emission,and annihilation of dislocations on the IGBs.

关键词： 6061 Al alloy hot-roll bonding vacuum mechanical properties interfacial grain boundaries

mechanical properties of Collagen Biomimetic Films Formed in the Presence of Calcium,Silica and Chitosan

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Journal of Bionic Engineering 2008年第2期5卷 149-158页

作者： Mihai Chirita Medical Bioengineering Faculty Medicine and Pharmacy University "Gr.T.Popa"Iasi 7000115Romania

Using eucollagen solutions from ox hide, we cast collagen films to assess the influence of calcium and silica on the reconstitution of the fibrous structure of collagen. The tensile strength and the breaking elongation of the reconstituted collagen films were measured and analysed. Significant differences were observed between reconstituted collagen films with and without calcium and silica. The breaking elongation of the films obtained in the presence of silica was significantly greater, and the degradation was lower than other films of reconstituted collagen. Collagen and chitosan do not exist together as blends in nature, but the specific properties of each may be used to produce in biomimetic way man-made blends with biomedical applications, that confer unique structural, mechanical （detail） and in vivo properties.

关键词： modified collagen biomimetic films chitosan biomaterials biopolymers mechanical properties

mechanical properties and microstructures of a wrought AZ91 alloy

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Rare Metals 2004年第3期23卷 220-225页

作者： YANYunqi ZHANGTingjie ZHOULian DENGJu TitaniumResearchCenter NorthwestInstituteforNonferrousMetalResearchXi＇an710016China TitaniumResearchCenter NorthwestInstituteforNonferrousMetalResearchXi＇an710016China

Effects of hot plastic deformation on microstructures and tensile propertiesof AZ91 alloy were investigated. Compared with as-T4 microstructures, the as-extruded samples ofAZ91 alloy with fine grains exhibit better strength and ductility due to dynamic *** succeeded rotation forging also provides finer grains while the strength increases, but theelongation decreases. Simultaneously, wrought AZ91 alloy shows more balance properties than as-T4condition ones. An interesting elongation of 228.5% is attained in the as-extruded AZ91 alloy inspite of the coarse grains with the size of 85 μm. The two-step method enhances the superplasticproperty of AZ91 alloy. The microstructure is still keeping the same scale of grains aftersuperplastic testing.

关键词： AZ91 alloy wrought mechanical properties microstructures

mechanical properties and microstructure characteristics of lattice-surfaced PEEK cage fabricated by high-temperature laser powder bed fusion

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Journal of Materials Science & Technology 2022年第30期125卷 105-117页

作者： Peng Chen Jin Su Haoze Wang Lei Yang Haosong Cai Maoyuan Li Zhaoqing Li Jie Liu Shifeng Wen Yan Zhou Chunze Yan Yusheng Shi State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China School of Logistics Engineering Wuhan University of TechnologyWuhan430081China Faculty of Engineering China University of GeosciencesWuhan430079China

Porous structure design on the contact surface is crucial to promote the osseointegration of the intervertebral cage while preventing subsidence and ***,the stress response will undergo significant changes for the current random porous cages,which can directly affect the mechanical properties and long-term ***,this paper proposed a newly designed polyetheretherketone(PEEK)cage with the triply periodic minimal surface(TPMS)-structured lattice surfaces to provide tailored 3 D microporosity and studied the mechanical performance,stress/strain responses,and microstructure changes in *** lattice-surfaced PEEK cage mainly exhibits a multiple-point-plane stress transfer *** compression modulus and elastic limit can be adjusted by controlling the area of the Diamond TPMS surface while the energy absorption efficiency remains *** microstructure of high-strength PEEK is featured by the radial pattern ***,the double-stranded orthorhombic phase is more ordered,and the benzene plane subunit and lattice volume become more expanded.

关键词： Additive manufacturing Laser powder bed fusion Polyetheretherketone Intervertebral cage mechanical properties

mechanical properties and enhancement mechanisms of titanium-graphene nanocomposites

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Acta Mechanica Sinica 2020年第4期36卷 855-865页

作者： Wanhong Tang Jie Zhang Jianyang Wu Jinyou Shao Peng Ding Guozhen Hou Xiaoming Chen Micro-and Nanotechnology Research Center State Key Laboratory for Manufacturing Systems EngineeringXi'an Jiaotong UniversityXi'an 710049China Electronic Materials Research Lab Key Lab of the Ministry of EducationXi’an Jiaotong UniversityXi’an 710049China Department of Physics Jiujiang Research Institute and Research Institute for Biomimetics and Soft MatterFujian Provincial Key Laboratory for Soft Functional Materials ResearchXiamen UniversityXiamen 361005China

Molecular dynamics(MD)simulations of the titanium-graphene nanocomposites(TiGNCs)under uniaxial tension are carried out to investigate the mechanical properties and reinforcement mechanism of graphene in *** is found that introduction of mechanically robust graphene limits the strain-induced dislocation and araorphization and thereby highly improves the mechanical properties of metallic titanium that are greatly affected by the crystal stacking orientation of graphene and titanium *** thickness of titanium layers,interface interaction and working temperature play an important role in the mechanical strength and elastic moduli of *** results show the mechanical properties of TiGNCs are monotonically enhanced with reduction of the titanium layer thickness and working temperature,and the Young5s modulus obtained by MD simulation are higher than that predicted by the rule of mixture(ROM)due to consideration of interfacial interaction in computational *** addition,once the critical thickness of titanium layer is reached,graphene wrinkles are induced in composites because of Poisson's effect induced large lateral compression stress in the interface *** study provides helpful insights into fundamental understanding reinforcing mechanism of graphene and ultimately contribute to the optimal design and performance of mechanically robust graphene-based metallic composites.

关键词： mechanical properties Enhancement mechanisms Titanium-graphene composites Wrinkling Molecular dynamics

mechanical properties and damage characteristics of solidified body-coal combination in continuous driving and gangue backfilling

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International Journal of Mining Science and Technology 2023年第10期33卷 1217-1228页

作者： Yi Tan Hao Cheng Wenbing Guo Erhu Bai Shaopu Zhang Yu Wang Zihao Li School of Energy Science and Engineering Henan Polytechnic UniversityJiaozuo 454000China State Collaborative Innovation Center of Coal Work Safety and Clean-Efficiency Utilization Henan Polytechnic UniversityJiaozuo 454000China

Recovery of the coal buried under buildings,railways and water bodies and the residual coal in irregularly arranged fully mechanized mining faces is a common engineering problem facing underground coal *** this study,a mining technology of continuous driving and gangue backfilling(CDGB)was *** technology,which can not only alleviate ground subsidence and gangue discharge,but also release the above-mentioned coals,contributes to green and efficient sustainable development of *** stability of the system of the solidified body-reserved coal pillar combination(S-C combination)is crucial to the CDGB ***,it is of great significance to explore the mechanical and damage characteristics of S-C combination in the synergistic bearing ***,four sets of differentshaped S-C combination specimens were fabricated and a S-C combination bearing structure in CDGB was constructed to explore the differences in mechanical characteristics and damage modes of different-shaped S-C combination specimens during ***,their surface strain field evolutions and acoustic emission(AE)response characteristics in the load-bearing process were obtained with the aid of the digital image correlation technique and the AE signal monitoring ***,a damage evolution model based on AE parameters and mechanical parameters was established to clarify the damage evolution *** following results were obtained:(1)The free area of S-C combination can serve as a quantitative index to evaluate the stability of the overburden control system;(2)The concept of critical value k of the free area was first *** the free area exceeds the critical value k(free area ratio greater than 1.13),the deformation resistance and the free area changes becomes negatively correlated;(3)As the free area expands,the failure of the S-C combination specimen evolves from tensile failure to shear *** distribution characteristics of the axial strain f

关键词： Continuous driving and gangue backfilling Solidified body-coal combination mechanical properties Damage characteristics Digital image correlation technology Acoustic emission