检索结果-南通市图书馆

International Journal of Mining Science and Technology 2024年第8期34卷 1135-1150页

作者： Huasu Wang Jing Bi Yu Zhao Chaolin Wang Jiabao Ma College of civil engineering Guizhou UniversityGuiyang 550025China

The wetting-drying(W-D)cycle is a type of water–rock *** pore structure of rock,such as shape,size,distribution and pore throat,affects fluid storage and *** theory and experimental research on the evolution characteristics of pore damage during the wet-dry erosion process are highly important for determining W-D *** mass and velocity of liquid migration are related to the pore size,porosity,fluid properties,*** data show that the water absorption quality and velocity in rocks decrease with the number of wet-dry *** the same test time,the mass and velocity of the SI water absorption method are smaller than those of the FI *** these two conditions,the amount and rate of water absorption represent the degree of water–rock *** the pore evolution during the wet-dry cycling,an equation describing the motion of liquid in porous media was derived based on the imbibition-type separation *** experimental data are in excellent agreement with the calculated values of the *** characteristics can affect the area and degree of rock deterioration as well as the development rate of pores and *** on the interaction between permeability and pores,quantitative analysis of the weakening process(local damage)of rocks under W-D cycles can provide good reference indicators for evaluating the stability of geotechnical engineering.

关键词： W-D cycle Capillary absorption Pore characteristic Fractal theory Dynamic damage model

Identification of time-varying system and energy-based optimization of adaptive control in seismically excited structure

在线全文

学校读者我要写书评

暂无评论

Earthquake engineering and engineering Vibration 2024年第1期23卷 227-240页

作者： Elham Aghabarari Fereidoun Amini Pedram Ghaderi Department of civil engineering Iran University of Science and TechnologyTehran 16844Iran

The combination of structural health monitoring and vibration control is of great importance to provide components of smart *** synthetic algorithms have been proposed,adaptive control that is compatible with changing conditions still needs to be used,and time-varying systems are required to be simultaneously estimated with the application of adaptive *** this research,the identification of structural time-varying dynamic characteristics and optimized simple adaptive control are ***,reduced variations of physical parameters are estimated online using the multiple forgetting factor recursive least squares(MFRLS)***,the energy from the structural vibration is simultaneously specified to optimize the control force with the identified parameters to be *** is also performed based on the probability density function of the energy under the seismic excitation at any ***,the optimal control force is obtained by the simple adaptive control(SAC)algorithm and energy coefficient.A numerical example and benchmark structure are employed to investigate the efficiency of the proposed *** simulation results revealed the effectiveness of the integrated online identification and optimal adaptive control in systems.

关键词： integrated online identification time-varying systems structural energy multiple forgetting factor recursive least squares optimal simple adaptive control algorithm

Dispersion effect of nano-structure pyrolytic carbon on mechanical,electrical,and microstructural characteristics of cement mortar composite

在线全文

学校读者我要写书评

暂无评论

International Journal of Smart and Nano Materials 2024年第3期15卷 534-578页

作者： N.K.Karthikeyan S.Elavenil School of civil engineering Vellore Institute of TechnologyChennaiIndia

In material science,converting waste into nanomaterials by green technologies highlights the interest in producing sus-tainable carbon nanomaterial(SCN).This study first-ever uti-lized tyre-char as a Nano-Structure Pyrolytic Carbon(NSPC)to develop electrically conductive *** other car-bon nanomaterials,the efficiency of NSPC particle as an SCN in developing electrically conductive composites was investi-gated in terms of dispersion,mechanical,water absorption,electrical resistivity,and *** results of sedi-mentation and zeta potential(-19 mV)showed the excellent dispersion of NSPC particle in water with the combined effect of superplasticizer and *** compressive(40.37%)and flexural strength(10.76%)than that of plain cement mortar composite(CMC)is achieved with 2 wt.%and 1.5 wt.%of NSPC particle,*** water absorption rate and volume of permeable voids were reduced,exhibiting less *** percolation zone of AC and DC resis-tivity of NSPC composite ranges between 1 and 2 wt.%,and the established percolation threshold is at 2 wt.%.XRD analysis showed C-S-H formation consistently increased with curing age,and HR-SEM with EDAX analysis exhibits the dense micro-structure and well-distributed NSPC particle at the *** experimental outcomes significantly enhanced the relia-bility and provided a framework for tailoring NSPC particle as SCN for developing electrically conductive composite.

关键词： Sustainable nanomaterial dispersion mechanical properties electrical resistivity microstructure analysis

Rainfall-triggered waste dump instability analysis based on surface 3D deformation in physical model test

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第5期21卷 1549-1563页

作者： LI Hanlin JIN Xiaoguang HE Jie XUE Yunchuan YANG Zhongping School of civil engineering Chongqing UniversityChongqing 400038China

Landslide is the second largest natural disaster after earthquake. It is of significance to study the evolution laws and failure mechanism of landslides based on its surface 3D deformation information. Based on the rainfall-triggered waste dump instability model test, we studied the failure mechanisms of the waste dump by integrating surface deformation and internal slope stress and proposed novel parameters for identifying landslide stability. We developed a noncontact measurement device, which can obtain millimeter-level 3D deformation data for surface scene in physical model test;Then we developed the similar materials and established a test model for a waste dump. Based on the failure characteristics of slope surface, internal stress of slope body and displacement contours during the whole process, we divided the slope instability process in model test into four stages: rainfall infiltration and surface erosion, shallow sliding, deep sliding, and overall instability. Based on the obtained surface deformation data, we calculated the volume change during slope instability process and compared it with the point displacement on slope surface. The results showed that the volume change can not only reflect the slow-ultra acceleration process of slope failure, but also fully reflect the above four stages and reduce the fluctuations caused by random factors. Finally, this paper proposed two stability identification parameters: the volume change rate above the slip surface and the relative velocity of volume change rate. According to the calculation of these two parameters in model test, they can be used for study the deformation and failure mechanism of slope stability.

关键词： Waste dump stability Physical model test Surface 3D deformation Stability identification

Effect of recycled brick powder on the properties of selfcompacting fiber reinforced mortars produced with different cement types

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and civil engineering 2024年第5期18卷 743-759页

作者： Serkan ETLI Department of civil engineering Kahramanmaras Sutcu Imam UniversityKahramanmaraş46040Turkey

It is known that clay-based building materials such as bricks and tiles accumulate in landfills at the end of their useful *** an alternative,recycling clay-based building material can reduce the negative environmental *** brick powder(RBP)is obtained by grinding waste brick and tile collected from end-of-life *** the scope of the study,the use of self-compacting fiber reinforced mortars(SCFRMs)produced with RBP using CEM-I 42.5R and 52.5R class cements for two different cement classes was *** accordance with EFNARC,a water binding ratio of 0.42 was used to control the workability and strength of the *** the produced SCFRM,1%,2%,and 3%by weight binder Polypropylene(PP)fiber was added to the blends with 10%,20%,and 30%RBP substitutes.A total of 32 SCFRM mixes were produced and *** flexural and compressive strengths at 7,28,56,and 90 d were evaluated on the produced *** addition,porosity and water absorbency values were examined since these are significant for durability *** was observed that the use of RBP increases durability,and the use of fiber can have positive effects in terms of both durability and strength.

关键词： cement strength tile/brick dust self-compacting fiberized mortar

Effect of Size Change on Mechanical Properties of Monolayer Arsenene

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 206-212页

作者：郭娟刘贵立孙震宇 School of Architecture and civil engineering Shenyang University of TechnologyShenyang 110870China

The Young's modulus, shear modulus and Poisson's ratio of monolayer arsenene with different sizes were calculated by finite element method, so as to explore the influence of dimension and orientation on the mechanical properties of monolayer arsenene. The calculation results show that the small size has a significant effect on the mechanical properties of the monolayer arsenene. The smaller the size, the larger the Young's modulus and Poisson's ratio of the monolayer arsenene. The size change has a great influence on the Young's modulus of the arsenene handrail direction, and the Young's modulus of the zigzag direction is not sensitive to the size change. Similarly, the size change has a significant effect on the shear modulus of arsenene in the handrail direction, while the shear modulus in the zigzag direction has no significant effect on its size change. For the Poisson's ratio, the situation is just the opposite, and the effect of the size change on the Poisson's ratio of the arsenene zigzag direction is greater than that of the handrail direction.

关键词： finite element method arsenene size change mechanical properties

Nonlinear constitutive models of rock structural plane and their applications

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical engineering 2024年第3期16卷 790-806页

作者： Wenlin Feng Shuangjian Niu Chunsheng Qiao Dujian Zou School of civil and Environmental engineering Harbin Institute of TechnologyShenzhenChina Shenzhen Municipal engineering Corporation Shenzhen518000China School of civil engineering Beijing Jiaotong UniversityBeijing100044China

Structural planes play an important role in controlling the stability of rock engineering,and the influence of structural planes should be considered in the design and construction process of rock *** this paper,mechanical properties,constitutive theory,and numerical application of structural plane are studied by a combination method of laboratory tests,theoretical derivation,and program *** test results reveal the change laws of various mechanical parameters under different roughness and normal *** the pre-peak stage,a non-stationary model of shear stiffness is established,and threedimensional empirical prediction models for initial shear stiffness and residual stage roughness are *** nonlinear constitutive models are established based on elasto-plastic mechanics,and the algorithms of the models are developed based on the return mapping *** to a large number of statistical analysis results,empirical prediction models are proposed for model parameters expressed by structural plane characteristic ***,the discrete element method(DEM)is chosen to embed the constitutive models for practical *** running programs of the constitutive models have been compiled into the discrete element model *** comparison results between the proposed model and the Mohr-Coulomb slip model show that the proposed model can better describe nonlinear changes at different stages,and the predicted shear strength,peak strain and shear stiffness are closer to the test *** research results of the paper are conducive to the accurate evaluation of structural plane in rock engineering.

关键词： Structural plane engineering stability Roughness Normal stress Elasto-plastic constitutive model Discrete element method

Theoretical and experimental study on multiscale coupled Mohr-Coulomb shear strength criterion of fibre-reinforced sand

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Underground Space 2024年第1期14卷 53-69页

作者： Deluan Feng Yuxin Wang Shihua Liang School of civil and Transportation engineering Guangdong University of TechnologyGuangzhou 510006China

Fibre-reinforced sand(FRS)is a multiphase and multiscale geo-material,which is widely used in geotechnical engineering as supporting structure of excavation of underground space and reinforcement of foundation of underground structures,and its strength is determined by the properties of the heterogeneous substances of the FRS and their coupling mechanical *** order to investigate the influence of fibre characteristics and mechanical properties on the shear strength of the FRS,according to the microscopic interface slip effect generated by the interaction between sand particles and the interaction between these particles and fibre,the material phase of the FRS is divided to conceptualize a micro cell element of the FRS that is capable of reflecting the internal material characteristic information of the ***,based on the coordinated deformation condition between fibres and sand particles at the microscale and the couple stress theory that is capable of effectively describing the discontinuous mechanical responses at the sand-fibre interface,a mesomechanism-based multiscale Mohr–Coulomb shear strength criterion of the FRS is derived,and the yield locus of the FRS is also drawn on the p ***,a series of FRS samples with different fibre content and fibre length were prepared by adopting the freezing method,and consolidated and drained triaxial compression tests were conducted on these samples to validate the proposed multiscale coupled Mohr–Coulomb shear strength *** show that the multiscale coupled Mohr–Coulomb shear strength criterion is capable of effectively reproducing and predicting the yield strength of the *** yield locus of the FRS extends outwards as fibre content and fibre length *** yield stress of the FRS predicted by the proposed multiscale coupled Mohr–Coulomb shear strength criterion is in good agreement with that of the test result.

关键词： Multiscale coupling Fibre-reinforced sand(FRS) Interface slip effect Physical mechanism Shear strength criterion

A New Formulation of the Scaled Boundary Finite Element Method for Heterogeneous Media:Application to Heat Transfer Problems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2024年第2期37卷 285-296页

作者： Nima Noormohammadi Nazanin Pirhaji Khouzani Department of civil engineering Isfahan University of TechnologyIsfahan84156-83111Iran

The solution to heat transfer problems in two-dimensional heterogeneous media is attended based on the scaled boundary finite element method(SBFEM)coupled with equilibrated basis functions(EqBFs).The SBFEM reduces the model order by scaling the boundary solution onto the inner *** this end,tri-lateral elements are emanated from a scaling center,followed by the development of a semi-analytical solution along the radial direction and a finite element solution along the circumferential/boundary *** discretization is thus limited to the boundaries of the model,and the semi-analytical radial solution is found through the solution of an eigenvalue problem,which restricts the methods’applicability to heterogeneous *** this research,we first extracted the SBFEM formulation considering the heterogeneity of the ***,we replaced the semi-analytical radial solution with the EqBFs and removed the eigenvalue solution step from the *** varying coefficients of the partial differential equation(PDE)resulting from the heterogeneity of the media are replaced by a finite series in the radial and circumferential directions of the element.A weighted residual approach is applied to the radial *** equilibrated radial solution series is used in the new formulation of the SBFEM.

关键词： Scaled boundary finite element method Equilibrated basis functions Heat transfer

Impact and mechanism of bisphosphonate depressant 1-hydroxypropane-1,1-diphosphonic acid on flotation decalcification of dolomite-rich magnesite ore

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2024年第7期34卷 1017-1032页

作者： Wengang Liu Xudong Chen Wenbao Liu Naixu Zhang Yong Mao Ying Guo School of Resources&civil engineering Northeastern UniversityShenyang 110819China

Given the depletion of high-quality magnesite deposits and the rising demand for high-end magnesium materials,the separation and utilization of high-calcium magnesite ores have become ***,the similar surface properties and solubility of semi-soluble salt-type minerals,pose significant challenges for the utilization of dolomite-rich magnesite *** this study,1-hydroxypropane-1,1-di phosphonic acid(HPDP)was identified for the first time as a high-performance depressant for *** tests,including contact angle measurements,ζ potential analysis,X-ray photoelectron spectroscopy,and atomic force microscopy,were conducted to elucidate the interfacial interaction mechanisms of HPDP on the surfaces of the two minerals at different ***,molecular modeling calculations were used to detail the spatial matching relationship between HPDP and the crystal faces of the two *** was emphasized that HPDP specifically adsorbed onto the dolomite surface by forming calcium phosphonate,ensuring that the dolomite surface remained hydrophilic and ***,it was found that the adsorption strength of HPDP on the mineral surfaces depended on the activity of the metal sites and their spatial *** findings provide a theoretical foundation for the molecular design of flotation reagents for high-calcium magnesite ores.

关键词： Depressant Interfacial mechanism Magnesite Dolomite DFT Decalcification