检索结果-南通市图书馆

THE　INFLUENCE　OF　THE　SECONDARY　normal　stress　DIFFERENCE　OF　VISCOELASTIC　FLUID　ON　ECCENTRIC　CAPSULE　FLOW

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 1995年第1期7卷 85-91页

作者： Pan Da-lin(Guangdong Institute of of Technology,Guangzhou 510090, P. R. China) Guangdong Inst of Technology Guangzhou China

A rheological analysis of the flow of a very long, denser-than-liquid carrier, cylindrical capsule in a horizontal pipeline is presented. The analysis indicate that secondary normal stress difference of viscoelastic fluid may balance with the force caused by the difference of densities and stabilize the POsition of capsule in pipeline.

关键词： capsule flow normal stress viscoelastic fluid.

Parameter Estimations of the TFR Model Under Exponential Distribution at a normal stress

在线全文

学校读者我要写书评

暂无评论

Chinese Quarterly Journal of Mathematics 2009年第2期24卷 234-238页

作者： WANG Yu Department of Mathematics and Information Science Qinghai Normal University Xining 810008China

The TFR（Tampered Failure Rate） model was proposed by Bhattacharyya and Soejoeti（1989） for step-stress accelerated life tests, On step-stress completely accelerated test occasions, the paper gives a method of estim... 详细信息

关键词： exponential disteribution TFR model CE model step-stress completely accelerated test normal stress

Shear band evolution and acoustic emission characteristics of sandstone containing non-persistent flaws

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2期16卷 497-513页

作者： Shuting Miao Peng-Zhi Pan Chuanqing Zhang Lei Huo State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China CASIC Research Institute of Intelligent Decision Engineering Wuhan430040China

Direct shear tests were conducted on sandstone specimens under different constant normal stresses to study the coalescence of cracks between non-persistent flaws and the shear sliding characteristics of the shear-formed *** image correlation and acoustic emission(AE)techniques were used to monitor the evolution of shear bands at the rock bridge area and microcracking *** experimental results revealed that the shear stresses corresponding to the peak and sub-peak in the stressdisplacement curve are significantly affected by the normal *** localization bands emerged at both the tip of joints and the rock bridge,and their extension and interaction near the peak stress caused a surge in the AE hit rate and a significant decrease in the AE b *** and curvilinear strain bands were detected at low normal stress,while high normal stress generally led to more microcracking events and longer coplanar cracks at the rock bridge ***,an increase in normal stress resulted in a higher AE count rate and more energetic AE events during friction sliding along the shearformed *** was observed that the elastic energy released during the crack coalescence at the prepeak stage was much greater than that released during friction sliding at the post-peak *** than 75%of AE events were located in the low-frequency band(0e100 kHz),and this proportion continued to rise with increasing normal ***,more AE events of low AF value and high RA value were observed in specimens subjected to high normal stress,indicating that greater normal stress led to more microcracks of shear nature.

关键词： Shear band evolution Acoustic emission(AE) Crack coalescence normal stress Shear sliding

Experimental investigation on shear strength deterioration at the interface between different rock types under cyclic loading

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 Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3063-3079页

作者： Qiong Wu Zhiqi Liu Huiming Tang Liangqing Wang Xiaoxue Huo Zhen Cui Shiyu Li Bo Zhang Zhiwei Lin Faculty of Engineering China University of GeosciencesWuhan430074China Guangxi Fangchenggang Beitou Environmental Protection Water Co. Ltd.Fangchenggang538021China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

The shear strength deterioration of bedding planes between different rock types induced by cyclic loading is vital to reasonably evaluate the stability of soft and hard interbedded bedding rock slopes under earthquake;however,rare work has been devoted to this subject due to lack of *** this study,experimental investigations on shear strength weakening of discontinuities with different joint wall material(DDJM)under cyclic loading were conducted by taking the interface between siltstone and mudstone in the Shaba slope of Yunnan Province,China as research objects.A total of 99 pairs of similar material samples of DDJM(81 pairs)and discontinuities with identical joint wall material(DIJM)(18 pairs)were fabricated by inserting plates,engraved with typical surface morphology obtained by performing three-dimensional laser scanning on natural DDJMs sampled from field,into mold *** shear tests were conducted on these samples to study their shear strength changes with the cyclic number considering the effects of normal stress,joint surface morphology,shear displacement amplitude and shear *** results indicate that the shear stress *** displacement curves under each shear cycle and the peak shear strength *** number curves of the studied DDJMs are between those of DIJMs with siltstone and mudstone,while closer to those of DIJMs with *** peak shear strengths of DDJMs exhibit an initial rapid decline followed by a gradual decrease with the cyclic number and the decrease rate varies from 6%to 55.9%for samples with varied surface morphology under different testing *** normal stress,joint surface morphology,shear displacement amplitude and shear rate collectively influence the shear strength deterioration of DDJM under cyclic shear loading,with the degree of influence being greater for larger normal stress,rougher surface morphology,larger shear displacement amplitude and faster shear rate.

关键词： Discontinuities with different joint wall material(DDJM) Discontinuities with identical joint wall material(DIJM) Cyclic shear test Shear strength deterioration Joint surface morphology Shear displacement amplitude Shear rate normal stress

Nonlinear constitutive models of rock structural plane and their applications

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 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

Shear behaviour of anchored jointed rock mass under different engineering conditions considering damage and joint surface morphology

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 2023年第6期13卷 316-334页

作者： Zenghui Zhao Wei Sun Shaojie Chen Hao Liu College of Energy and Mining Engineering Shandong University of Science and TechnologyQingdao 266590China State Key Laboratory of Strata Intelligent Control and Green Mining Co-founded by Shandong Province and the Ministry of Science and Technology Shandong University of Science and TechnologyQingdao 266590China Department of Petroleum Engineering China University of Petroleum-BeijingBeijing 102249China

According to different geological conditions and engineering disturbance,three dimensional numerical models of anchored jointed rock mass with two kinds of boundary conditions of constant normal load(CNL)and constant normal stiffness(CNS)were constructed considering the ductility damage of rockbolt,the stiffness degradation of grouting layer and the joint surface *** effects of anchorage angle,joint surface morphology,and boundary conditions on the shear performance of anchorage system were analyzed,and the failure characteristics under different working conditions were ***,the analytical solution of shear strength of anchored system was *** show that the larger the anchorage angle is,the more serious the necking phenomenon of rockbolt will *** damage degree of the bonding layer and the horizontal displacement of the bedding rock mass decrease with the increase of the joint surface *** CNL condition is to instantaneously apply high normal stress,and the CNS condition is to gradually form a high normal stress environment through the superposition of increment on the basis of the initial value,which can resist greater transverse *** is equivalent to enhancing the ductility of the *** shear strength of the system increases with the increase of normal stress and normal *** the normal stiffness will underestimate the shear strength.

关键词： Anchored jointed rock mass normal stress normal stiffness Progressive damage

Reflection and transmission of quasi-plane waves at the interface of piezoelectric semiconductors with initial stresses

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2021年第7期42卷 951-968页

作者： S.A.SAHU S.NIRWAL S.MONDAL Department of Mathematics and Computing Indian Institute of Technology(ISM)Dhanbad 826004JharkhandIndia

We examine the reflection and transmission phenomena of quasi-longitudinal plane(QP)waves in an AlN-ZnO laminated composite *** structure is designed under the influence of the initial stresses in which one carrier piezoelectric semiconductor(PSC)half-space is in welded contact with another PSC *** secular equations in the transversely isotropic PSC material are derived from the general dynamic equation,taking the initial stresses into *** is shown that the incident quasi-longitudinal wave(QP-mode)at the interface generates four types of reflected and transmitted waves,namely,QP wave,quasi-transverse(QSV)wave,electric-acoustic(EA)wave,and carrier plane(CP)*** algebraic equations are obtained by imposing the boundary conditions on the common interface of the laminated *** and transmission coefficients of waves are obtained by implementing Cramer’s *** impacts of the initial stresses and exterior electric biasing field on the reflection and transmission coefficients of waves are investigated and presented graphically.

关键词： piezoelectric semiconductor(PSC) electric biasing field normal stress shear stress

Limit equilibrium method for slope stability based on assumed stress on slip surface

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2016年第11期23卷 2972-2983页

作者：邓东平赵炼恒李亮 School of Civil Engineering Central South University

In the limit equilibrium framework, two- and three-dimensional slope stabilities can be solved according to the overall force and moment equilibrium conditions of a sliding body. In this work, based on Mohr-Coulomb(M-C) strength criterion and the initial normal stress without considering the inter-slice(or inter-column) forces, the normal and shear stresses on the slip surface are assumed using some dimensionless variables, and these variables have the same numbers with the force and moment equilibrium equations of a sliding body to establish easily the linear equation groups for solving them. After these variables are determined, the normal stresses, shear stresses, and slope safety factor are also obtained using the stresses assumptions and M-C strength criterion. In the case of a three-dimensional slope stability analysis, three calculation methods, namely, a non-strict method, quasi-strict method, and strict method, can be obtained by satisfying different force and moment equilibrium conditions. Results of the comparison in the classic two- and three-dimensional slope examples show that the slope safety factors calculated using the current method and the other limit equilibrium methods are approximately equal to each other, indicating the feasibility of the current method; further, the following conclusions are obtained: 1) The current method better amends the initial normal and shear stresses acting on the slip surface, and has the identical results with using simplified Bishop method, Spencer method, and Morgenstern-Price(M-P) method; however, the stress curve of the current method is smoother than that obtained using the three abovementioned methods. 2) The current method is suitable for analyzing the two- and three-dimensional slope stability. 3) In the three-dimensional asymmetric sliding body, the non-strict method yields safer solutions, and the results of the quasi-strict method are relatively reasonable and close to those of the strict method, indicatin

关键词： two-dimensional slope three-dimensional slope limit equilibrium analysis normal stress shear stress safety factor

ANALYTICAL SOLUTION OF RESTRAINED TORSIONAL stressES AND DISPLACEMENT FOR RECTANGULAR- SECTION BOX BAR WITH HONTYCOMB CORE

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2004年第7期25卷 779-785页

作者：张英世张行 Department of Flight Vehicle Design and Applied Mechanics

Differential equation of restrained torsion for rectangular-section box bar with honeycomb core was established and solved by using the method of undetermined ***-dimension normal stress, shear stress acting in the faceplate and shear stress acting in the honeycomb-core and warping displacement were deduced. Numerical analysis shows the normal stress attenuates quickly along x-axis. normal stress acting on the cross section at a distance of 20 h from the fixed end is only one per cent of that acting on the fixed end.

关键词： honeycomb structure constrain twist attenuation rectangular section box bar normal stress shear stress warping displacement