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Stability and accuracy of central difference method for real-time dynamic substructure testing considering mass participation coefficient
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作者 Zheng Lichang Xu Guoshan +3 位作者 Yang Ge Wang Zhen Yang Kaibo Zheng Zhenyun 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第3期625-636,共12页
For real-time dynamic substructure testing(RTDST),the influence of the inertia force of fluid specimens on the stability and accuracy of the integration algorithms has never been investigated.Therefore,this study prop... For real-time dynamic substructure testing(RTDST),the influence of the inertia force of fluid specimens on the stability and accuracy of the integration algorithms has never been investigated.Therefore,this study proposes to investigate the stability and accuracy of the central difference method(CDM)for RTDST considering the specimen mass participation coefficient.First,the theory of the CDM for RTDST is presented.Next,the stability and accuracy of the CDM for RTDST considering the specimen mass participation coefficient are investigated.Finally,numerical simulations and experimental tests are conducted for verifying the effectiveness of the method.The study indicates that the stability of the algorithm is affected by the mass participation coefficient of the specimen,and the stability limit first increases and then decreases as the mass participation coefficient increases.In most cases,the mass participation coefficient will increase the stability limit of the algorithm,but in specific circumstances,the algorithm may lose its stability.The stability and accuracy of the CDM considering the mass participation coefficient are verified by numerical simulations and experimental tests on a three-story frame structure with a tuned liquid damper. 展开更多
关键词 real-time dynamic substructure testing central difference method STABILITY mass participation coefficient tuned liquid damper
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Testing method of rock structural plane using digital drilling
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作者 Qi Wang Yuncai Wang +4 位作者 Bei Jiang Hongke Gao Fenglin Ma Dahu Zhai Songlin Cai 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第7期2563-2578,共16页
The rock mass consists of rock blocks and structural planes,which can reduce its integrity and strength.Therefore,accurately obtaining the characteristics of the rock mass structural plane is a prerequisite for evalua... The rock mass consists of rock blocks and structural planes,which can reduce its integrity and strength.Therefore,accurately obtaining the characteristics of the rock mass structural plane is a prerequisite for evaluating stability and designing supports in underground engineering.Currently,there are no effective testing methods for the characteristic parameters of the rock mass structural plane in underground engineering.The paper presents the digital drilling technology as a new testing method of rock mass structural planes.Flawed rock specimens with cracks of varying widths and angles were used to simulate the rock mass structural planes,and the multifunctional rock mass digital drilling test system was employed to carry out the digital drilling tests.The analysis focuses on the variation laws of drilling parameters,such as drilling pressure and drilling torque,affected by the characteristics of prefabricated cracks,and clarifies the degradation mechanism of rock equivalent compressive strength.Additionally,an identification model for the characteristic parameters of rock mass structural planes during drilling is established.The test results indicate that the average difference of the characteristics of prefabricated cracks identified by the equivalent compressive strength is 2.45°and 0.82 mm,respectively.The identification model while drilling is verified to be correct due to the high identification accuracy.Based on this,a method for testing the characteristic parameters of the surrounding rock structural plane while drilling is proposed.The research offers a theoretical and methodological foundation for precise in situ identification of structural planes of the surrounding rock in underground engineering. 展开更多
关键词 Structural planes in the rock mass Digital drilling Drilling parameters Equivalent compressive strength testing method
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Determination of Material Parameters of EVA Foam under Uniaxial Compressive Testing Using Hyperelastic Models
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作者 Nattapong Sangkapong Fasai Wiwatwongwana Nattawit Promma 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第3期800-804,共5页
The objective of this research was to determine the mechanical parameter from EVA foam and also investigate its behavior by using Blatz-Ko,Neo-Hookean,Mooney model and experimental test.The physical characteristic of ... The objective of this research was to determine the mechanical parameter from EVA foam and also investigate its behavior by using Blatz-Ko,Neo-Hookean,Mooney model and experimental test.The physical characteristic of EVA foam was also evaluated by scanning electron microscopy(SEM).The results show that Blatz-Ko and Neo-Hookean model can fit the curve at 5%and 8%strain,respectively.The Mooney model can fit the curve at 50%strain.The modulus of rigidity evaluated from Mooney model is 0.0814±0.0027 MPa.The structure of EVA foam from SEM image shows that EVA structure is a closed cell with homogeneous porous structure.From the result,it is found that Mooney model can adjust the data better than other models.This model can be applied for mechanical response prediction of EVA foam and also for reference value in engineering application. 展开更多
关键词 hyperelastic models modulus of rigidity EVA foam curve fitting method strain energy function uniaxial compressive testing
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Application of the extended Fourier amplitude sensitivity testing(FAST)method to inflated,axial stretched,and residually stressed cylinders 被引量:1
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作者 H.ASGHARI H.TOPOL +1 位作者 B.MARKERT J.MERODIO 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第12期2139-2162,共24页
This paper is dedicated to applying the Fourier amplitude sensitivity test(FAST)method to the problem of mixed extension and inflation of a circular cylindrical tube in the presence of residual stresses.The metafuncti... This paper is dedicated to applying the Fourier amplitude sensitivity test(FAST)method to the problem of mixed extension and inflation of a circular cylindrical tube in the presence of residual stresses.The metafunctions and the Ishigami function are considered in the sensitivity analysis(SA).The effects of the input variables on the output variables are investigated,and the most important parameters of the system under the applied pressure and axial force such as the axial stretch and the azimuthal stretch are determined. 展开更多
关键词 sensitivity analysis(SA) Fourier amplitude sensitivity test(FAST)method cylindrical inflation nonlinear elasticity
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Research on the Testing Methods of Instrumental System in the Marine Magnetic Survey 被引量:1
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作者 边刚 刘雁春 +2 位作者 于波 肖付民 卞光浪 《Marine Science Bulletin》 CAS 2007年第2期1-11,共11页
Testing methods of instrumental system in the marine magnetic survey have been studied in this paper, and the feasibility of each method has been testified by the observed data. The conclusion shows that the method br... Testing methods of instrumental system in the marine magnetic survey have been studied in this paper, and the feasibility of each method has been testified by the observed data. The conclusion shows that the method brought out can effectively eliminate the systematic error caused by the instrumental system, and greatly improve the surveying precision and the reliability of the survey results. 展开更多
关键词 Marine magnetic survey instrumental system testing method
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Analysis of the integrated test and evaluation methods of tidal current energy generating devices in the offshore testing site
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作者 郭文瑞 朱永强 +3 位作者 叶青 李雪临 王鑫 段春明 《Marine Science Bulletin》 CAS 2014年第2期60-71,共12页
Actual sea condition testing and inspection and evaluation method research are carried out for tidal energy devices to provide scientific and effective technical support for the ocean high-tech achievement transformat... Actual sea condition testing and inspection and evaluation method research are carried out for tidal energy devices to provide scientific and effective technical support for the ocean high-tech achievement transformation and marine renewable energy development. By analyzing three core indicators, including the power output characteristics of the tidal current device, the generating capacity, energy conversion efficiency, proposed the test contents and evaluation methods of indicators are proposed in this paper; and based on the research of wind farms, power quality testing and assessment methods of offshore tidal energy device are proposed; given the security access to the test contents of tidal current energy device, tidal current energy device running conditions in the testing ground are comprehensively assessed. 展开更多
关键词 testing ground tidal current energy generating device integrated test evaluation method
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Real-time embedded software testing method based on extended finite state machine 被引量:6
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作者 Yongfeng Yin Bin Liu Hongying Ni 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2012年第2期276-285,共10页
The reliability of real-time embedded software directly determines the reliability of the whole real-time embedded sys- tem, and the effective software testing is an important way to ensure software quality and reliab... The reliability of real-time embedded software directly determines the reliability of the whole real-time embedded sys- tem, and the effective software testing is an important way to ensure software quality and reliability. Based on the analysis of the characteristics of real-time embedded software, the formal method is introduced into the real-time embedded software testing field and the real-time extended finite state machine (RT-EFSM) model is studied firstly. Then, the time zone division method of real-time embedded system is presented and the definition and description methods of time-constrained transition equivalence class (timeCTEC) are presented. Furthermore, the approaches of the testing sequence and test case generation are put forward. Finally, the proposed method is applied to a typical avionics real- time embedded software testing practice and the examples of the timeCTEC, testing sequences and test cases are given. With the analysis of the testing result, the application verification shows that the proposed method can effectively describe the real-time embedded software state transition characteristics and real-time requirements and play the advantages of the formal methods in accuracy, effectiveness and the automation supporting. Combined with the testing platform, the real-time, closed loop and automated simulation testing for real-time embedded software can be realized effectively. 展开更多
关键词 real-time system real-time embedded software for- mal method extended finite state machine (EFSM) testing se- quence test case.
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Nondestructive testing method of wood moisture content based on a planar capacitance sensor model 被引量:3
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作者 WANG Jue LUO Yue-sheng LIU Shao-gang 《Forestry Studies in China》 CAS 2010年第3期142-146,共5页
For our research, a new hybrid experimental-computational method is presented. We applied a least squares fitting method (LSFM) to reconstruct the wood moisture content (WMC) from the data measured with a planar c... For our research, a new hybrid experimental-computational method is presented. We applied a least squares fitting method (LSFM) to reconstruct the wood moisture content (WMC) from the data measured with a planar capacitance sensor. A boundary element method (BEM) was used to compute the relationship between capacitance and the dielectric constant. A functional relationship between MC and the dielectric constant was identified by LSFM. The agreement of this final computation result with the experimental data indicates that this method can be used to estimate the WMC quickly and effectively with engineering analysis. Compared with popular statistical methods, a large number of experiments are avoided, some costs of testing are reduced and the efficiency of testing is enhanced. 展开更多
关键词 planar capacitance sensor nondestructive testing wood moisture content boundary element method least squares fitring method
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Establishment of Microbial Limit Test Methods for Two Hospital Preparations
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作者 Renhui YANG Yongmin CHEN +3 位作者 Yufen XIA Yongyue GAO Yuling LUO Xianmei XU 《Agricultural Biotechnology》 CAS 2023年第3期92-94,127,共4页
[Objectives] This study was conducted to establish microbial limit test methods for traditional Chinese medicine preparations Yunpi Granules and Bupi Qiangli Paste. [Methods] According to General Rules of Part IV of C... [Objectives] This study was conducted to establish microbial limit test methods for traditional Chinese medicine preparations Yunpi Granules and Bupi Qiangli Paste. [Methods] According to General Rules of Part IV of Chinese Pharmacopoeia, applicability tests were conducted on microbial limit test methods for the above two traditional Chinese medicine preparations by the plate method. [Results] The established methods showed recovery values in the range of 0.5-2.0 for both experimental strains, and the control bacteria could be detected in the experimental group, but not in the negative control group. [Conclusions] The microbial limit test methods were reliable for the two traditional Chinese medicine preparations and could be used for quality control. 展开更多
关键词 Yunpi Granules Bupi Qiangli Paste Microbial limit test method applicability test
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Applicability of Microbial Limit Test Method for Qingyan Zhisou Powder
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作者 Changping TAI Yuanfeng YANG +3 位作者 Yongmin CHEN Yuling LUO Keqin MA Renhui YANG 《Agricultural Biotechnology》 CAS 2023年第2期117-120,共4页
[Objectives]This study was conducted to establish a microbial limit test method for Qingyan Zhisou Powder.[Methods]Applicability tests were carried out according to Microbial Limit Tests of Non-sterile Products,Genera... [Objectives]This study was conducted to establish a microbial limit test method for Qingyan Zhisou Powder.[Methods]Applicability tests were carried out according to Microbial Limit Tests of Non-sterile Products,General Rules 1105-1107 of Part IV of Chinese Pharmacopoeia,2020.[Results]Qingyan Zhisou Powder had a strong bacteriostatic effect on Pseudomonas aeruginosa.After increasing the dilution ratio(1:40),the bacteriostatic effect was obviously eliminated.When the total number of aerobic microbes was determined by the test liquid dilution method(1:40),the recovery values were in the range of 50%-200%;and when using the test liquid(1:10)to determine the total number of mold and yeasts,the recovery ranged from 50%to 200%.Escherichia coli,Salmonella and bile-tolerant Gram-negative bacteria were detected by both the routine method and dilution method in experimental groups.[Conclusions]The microbial limit test of Qingyan Zhisou Powder adopted the test liquid dilution method,and the routine method could be used for the test of Escherichia coli,Salmonella and bile-tolerant Gram-negative bacteria.The applicability test of the method is feasible,with scientific and accurate results,and the method can effectively control the quality of the preparation and is recommended for popularization. 展开更多
关键词 Qingyan Zhisou Powder Microbial limit test method applicability
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A comprehensive testing method for global stability analysis of high arch dams 被引量:3
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作者 Lin Zhang Yuan Chen +2 位作者 Baoquan Yang Jianye Chen Chengqiu Hu 《Journal of Rock Mechanics and Geotechnical Engineering》 2012年第1期73-81,共9页
Hydropower projects are rapidly developing in China at present, and a number of high daras and large reservoirs are currently under construction or will soon be built. These large projects are mainly located on the gr... Hydropower projects are rapidly developing in China at present, and a number of high daras and large reservoirs are currently under construction or will soon be built. These large projects are mainly located on the great rivers in West China with complicated topographical and geological conditions. Evaluation of stability and safety of these high dam projects is an important topic. Geomechanical model test is one of the main methods to study the global stability of high dam and foundation. In this paper, a comprehensive testing method that combines overloading and strength reduction in a model is proposed. In this method, both the influence of excessive flooding and the effects of strength reduction of rock masses and weak structural planes on dam stability are considered. Thus, the comprehensive testing method can accurately incorporate multiple factors that affect the global stability of high dam and its foundation. Based on the failure testing principle and model similarity theory, a similarity relation formula for safety evaluation through comprehensive test is established. A new model material, temperature-dependent analogous material, is also developed. By rising the temperature and reducing the strength of the mod,~l material, the mechanical behaviors resulting from gradual strength reduction can be simulated. Thus, the comprehensive testing method is realized in a single model. For case studies, the comprehensive geomechanical model test is conducted for Jinpinlg I and Xiaowan high arch dam projects. 展开更多
关键词 geomechanical model comprehensive testing method temperature-dependent analo~ ous material engineeringapplication
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Model test of negative Poisson’s ratio cable for supporting super-largespan tunnel using excavation compensation method
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作者 Manchao He Aipeng Guo +4 位作者 Zhifeng Du Songyuan Liu Chun Zhu Shiding Cao Zhigang Tao 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第6期1355-1369,共15页
In recent years,there is a scenario in urban tunnel constructions to build super-large-span tunnels for traffic diversion and route optimization purposes.However,the increased size makes tunnel support more difficult.... In recent years,there is a scenario in urban tunnel constructions to build super-large-span tunnels for traffic diversion and route optimization purposes.However,the increased size makes tunnel support more difficult.Unfortunately,there are few studies on the failure and support mechanism of the surrounding rocks in the excavation of supported tunnel,while most model tests of super-large-span tunnels focus on the failure characteristics of surrounding rocks in tunnel excavation without supports.Based on excavation compensation method(ECM),model tests of a super-large-span tunnel excavation by different anchor cable support methods in the initial support stage were carried out.The results indicate that during excavation of super-large-span tunnel,the stress and displacement of the shallow surrounding rocks decrease,following a step-shape pattern,and the tunnel failure is mainly concentrated on the vault and spandrel areas.Compared with conventional anchor cable supports,the NPR(negative Poisson’s ratio)anchor cable support is more suitable for the initial support stage of the super-large-span tunnels.The tunnel support theory,model test materials,methods,and the results obtained in this study could provide references for study of similar super-large-span tunnels。 展开更多
关键词 Super-large-span tunnel Excavation compensation method(ECM) NPR(Negative Poisson’s ratio)anchor cable Model test
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Non-Destructive Testing of Structures Using Optical and Other Methods: A Review 被引量:1
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作者 A.Kroworz A.Katunin 《Structural Durability & Health Monitoring》 EI 2018年第1期1-17,共17页
Non-destructive testing (NDT) of structures is one of the most important tasksof the proper maintenance and diagnosis of machines and constructions structuralcondition. NDT methods contribute to the damage tolerance p... Non-destructive testing (NDT) of structures is one of the most important tasksof the proper maintenance and diagnosis of machines and constructions structuralcondition. NDT methods contribute to the damage tolerance philosophy used in theaircraft design methodology as well as many other operation and maintenance programsof machinery and constructions. The following study is focusing on overviewing animportant group of NDT methods: the optical and other ones, which found broadapplicability in scientific and industrial studies nowadays. The paper discusses theselected most widely applicable methods, namely, visual testing, ultrasonic testing,radiographic testing, infrared thermography as well as electronic speckle patterninterferometry and shearographic testing. Besides the basic principles of testing usingthese methods, their potential applications in various industrial and technologicalbranches are broadly discussed. The analysis as categorization of the NDT methodsprovided in this paper may help in selection of such methods in diagnosis of varioustypes of structures and defects and damage occurring in these structures. 展开更多
关键词 Non-destructive testing optical NDT methods testing of structures damageidentification
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A Mini Review on Testing Methods for Mechanical Properties of Natural Fibre Honeycomb Sandwich Structure and Fractography Analysis 被引量:1
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作者 Nahiyan Al-Azad Nur Hafidah Binti Dedifitrianto Mohd. Kamal Mohd. Shah 《Journal of Materials Science and Chemical Engineering》 2021年第5期29-38,共10页
This paper is a review of the past research of mechanical testing methods for natural fibre honeycomb sandwich structure as well as failure modes analysis at a microscopic level by using Scanning Electron Microscope (... This paper is a review of the past research of mechanical testing methods for natural fibre honeycomb sandwich structure as well as failure modes analysis at a microscopic level by using Scanning Electron Microscope (SEM). As the world is garnering attention towards renewable resources for environmental purposes, studies of natural fibre have been increasing as well as the application of natural fibre throughout various industries such as aerospace, automobiles, and construction sectors. This paper is started with brief information regarding the honeycomb sandwich structure, introduction to natural fibre, its applications as well as the factors affecting the performances of the structure. Next, the mechanical testing methods are listed out as well as the expected outcomes obtained from the respective testing. The mechanical properties are also identified by conducting lab tests according to the ASTM standard for sandwich and core structures. The microstructure of the deformed samples is then examined under Scanning Electron Microscope (SEM) by using different magnifications to study the failure mechanisms of the samples. The images obtained from the SEM test are analyzed by using fractography which will show the failure modes of the samples. This article is based on past research conducted by professional on the related topic. 展开更多
关键词 Natural Fibre Honeycomb Sandwich Structure testing methods ASTM Standard SEM test
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Testing methods for 1100 kV UHVDC transformer 被引量:2
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作者 Thomas Hammer Rene Wimmer +1 位作者 Karsten Loppach Ronny Fritsche 《Global Energy Interconnection》 2018年第2期103-107,共5页
1 Development of UHVDC transmission capabilities The economical development of China is closely connected with safe and reliable power supply.Load centers e.g.in central and eastern China need huge amounts of electric... 1 Development of UHVDC transmission capabilities The economical development of China is closely connected with safe and reliable power supply.Load centers e.g.in central and eastern China need huge amounts of electrical power.Available energy resources and consumption areas are often distributed inverse.As a consequence it is necessary to import electrical power to load center areas in an economic and efficient way. 展开更多
关键词 UHVDC In testing methods for 1100 kV UHVDC transformer
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Mobility and dynamic erosion process of granular flow:insights from numerical investigation using material point method
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作者 YU Fangwei SU Lijun +1 位作者 LI Xinpo ZHAO Yu 《Journal of Mountain Science》 SCIE CSCD 2024年第8期2713-2738,共26页
In order to understand the dynamics of granular flow on an erodible base soil,in this paper,a series of material point method-based granular column collapse tests were conducted to investigate numerically the mobility... In order to understand the dynamics of granular flow on an erodible base soil,in this paper,a series of material point method-based granular column collapse tests were conducted to investigate numerically the mobility and dynamic erosion process of granular flow subjected to the complex settings,i.e.,the aspect ratio,granular mass,friction and dilatancy resistance,gravity and presence of water.A set of power scaling laws were proposed to describe the final deposit characteristics of granular flow by the relations of the normalized run-out distance and the normalized final height of granular flow against the aspect ratio,being greatly affected by the complex geological settings,e.g.,granular mass,the friction and dilatancy resistance of granular soil,and presence of water in granular flow.An index of the coefficient of friction of granular soil was defined as a ratio of the target coefficient of friction over the initial coefficient of friction to quantify the scaling extent of friction change(i.e.,friction strengthening or weakening).There is a characteristic aspect ratio of granular column corresponding to the maximum mobility of granular flow with the minimum index of the apparent coefficient of friction.The index of the repose coefficient of friction of granular flow decreased gradually with the increase in aspect ratio because higher potential energy of granular column at a larger aspect ratio causes a larger kinetic energy of granular soil to weaken the friction of granular soil as a kind of velocity-related friction weakening.An increase in granular mass reduces gradually the indexes of the apparent and repose coefficients of friction of granular soil to enhance the mobility of granular flow.The mobility of granular flow increases gradually with the decrease in friction angle or increase in dilatancy angle of granular soil.However,the increase of gravity accelerates granular flow but showing the same final deposit profile without any dependence on gravity.The mobility of granular flow increases gradually by lowering the indexes of the apparent and repose coefficients of friction of granular flow while changing the surroundings,in turn,the dry soil,submerged soil and saturated soil,implying a gradually increased excessive mobility of granular flow with the friction weakening of granular soil.Presence of water in granular flow may be a potential catalyzer to yield a long run-out granular flow,as revealed in comparison of water-absent and water-present granular flows.In addition,the dynamic erosion and entrainment of based soil induced by granular flow subjected to the complex geological settings,i.e.,the aspect ratio,granular mass,gravity,friction and dilatancy resistance,and presence of water,were comprehensively investigated as well. 展开更多
关键词 Column collapse Granular flow Granular soil Material point method MOBILITY Numerical tests
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Application of excavation compensation method for enhancing stability and efficiency in shallow large-span rock tunnels
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作者 BIAN Wen-hui YANG Jun +2 位作者 ZHU Chun WANG Ke-xue XU Dong-ming 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第9期3242-3263,共22页
Engineering shallow,large-span rock tunnels challenges deformation control and escalates construction costs.This study investigates the excavation compensation method(ECM)and its associated technologies to address the... Engineering shallow,large-span rock tunnels challenges deformation control and escalates construction costs.This study investigates the excavation compensation method(ECM)and its associated technologies to address these issues.Utilizing five key technologies,the ECM effectively modulates radial stress post-excavation,redistributes stress in the surrounding rock,and eliminates tensile stress at the excavation face.Pre-tensioning measures further enhance the rock’s residual strength,establishing a new stability equilibrium.Field tests corroborate the method’s effectiveness,demonstrating a crown settlement reduction of 3–8 mm,a nearly 50%decrease compared to conventional construction approaches.Additionally,material consumption and construction duration were reduced by approximately 30%–35%and 1.75 months per 100 m,respectively.Thus,the ECM represents a significant innovation in enhancing the stability and construction efficiency of large-span rock tunnels,marking a novel contribution to the engineering field. 展开更多
关键词 excavation compensation method rocky tunnels shallow spanning tunnels tunnel support field test
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Dynamic failure process of expanded polystyrene particle lightweight soil under cyclic loading using discrete element method
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作者 Zhou Wei Hou Tianshun +3 位作者 Chen Ye Wang Qi Luo Yasheng Zhang Yafei 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第4期815-828,共14页
Expanded polystyrene(EPS)particle-based lightweight soil,which is a type of lightweight filler,is mainly used in road engineering.The stability of subgrades under dynamic loading is attracting increased research atten... Expanded polystyrene(EPS)particle-based lightweight soil,which is a type of lightweight filler,is mainly used in road engineering.The stability of subgrades under dynamic loading is attracting increased research attention.The traditional method for studying the dynamic strength characteristics of soils is dynamic triaxial testing,and the discrete element simulation of lightweight soils under cyclic load has rarely been considered.To study the meso-mechanisms of the dynamic failure processes of EPS particle lightweight soils,a discrete element numerical model is established using the particle flow code(PFC)software.The contact force,displacement field,and velocity field of lightweight soil under different cumulative compressive strains are studied.The results show that the hysteresis curves of lightweight soil present characteristics of strain accumulation,which reflect the cyclic effects of the dynamic load.When the confining pressure increases,the contact force of the particles also increases.The confining pressure can restrain the motion of the particle system and increase the dynamic strength of the sample.When the confining pressure is held constant,an increase in compressive strain causes minimal change in the contact force between soil particles.However,the contact force between the EPS particles decreases,and their displacement direction points vertically toward the center of the sample.Under an increase in compressive strain,the velocity direction of the particle system changes from a random distribution and points vertically toward the center of the sample.When the compressive strain is 5%,the number of particles deflected in the particle velocity direction increases significantly,and the cumulative rate of deformation in the lightweight soil accelerates.Therefore,it is feasible to use 5%compressive strain as the dynamic strength standard for lightweight soil.Discrete element methods provide a new approach toward the dynamic performance evaluation of lightweight soil subgrades. 展开更多
关键词 lightweight soil cyclic loading dynamic triaxial test discrete element method hysteresis curve
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Seismic effectiveness evaluation and optimized design of tie up method for securing museum collections
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作者 Wang Meng Yan Yi +3 位作者 Yang Weiguo Liu Pei Ge Jiaqi Ma Botao 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第3期741-763,共23页
To quantify the seismic effectiveness of the most commonly used fishing line tie up method for securing museum collections and optimize fixed strategies for exhibitions,shaking table tests of the seismic systems used ... To quantify the seismic effectiveness of the most commonly used fishing line tie up method for securing museum collections and optimize fixed strategies for exhibitions,shaking table tests of the seismic systems used for typical museum collection replicas have been carried out.The influence of body shape and fixed measure parameters on the seismic responses of replicas and the interaction behavior between replicas and fixed measures have been explored.Based on the results,seismic effectiveness evaluation indexes of the tie up method are proposed.Reasonable suggestions for fixed strategies are given,which provide a basis for the exhibition of delicate museum collections considering the principle of minimizing seismic responses and intervention.The analysis results show that a larger ratio of height of mass center to bottom diameter led to more intense rocking responses.Increasing the initial pretension of fishing lines was conducive to reducing the seismic responses and stress variation of the lines.Through comprehensive consideration of the interaction forces and effective securement,it is recommended to apply 20%of breaking stress as the initial pretension.For specific museum collections that cannot be effectively protected by the independent tie up method,an optimized strategy of a combination of fishing lines and fasteners is recommended. 展开更多
关键词 tie up method museum collections shaking table test seismic effectiveness optimized design
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A vector sum analysis method for stability evolution of expansive soil slope considering shear zone damage softening
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作者 Junbiao Yan Lingwei Kong +1 位作者 Cheng Chen Mingwei Guo 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第9期3746-3759,共14页
Slope stability analysis is a classical mechanical problem in geotechnical engineering and engineering geology.It is of great significance to study the stability evolution of expansive soil slopes for engineering cons... Slope stability analysis is a classical mechanical problem in geotechnical engineering and engineering geology.It is of great significance to study the stability evolution of expansive soil slopes for engineering construction in expansive soil areas.Most of the existing studies evaluate the slope stability by analyzing the limit equilibrium state of the slope,and the analysis method for the stability evolution considering the damage softening of the shear zone is lacking.In this study,the large deformation shear mechanical behavior of expansive soil was investigated by ring shear test.The damage softening characteristic of expansive soil in the shear zone was analyzed,and a shear damage model reflecting the damage softening behavior of expansive soil was derived based on the damage theory.Finally,by skillfully combining the vector sum method and the shear damage model,an analysis method for the stability evolution of the expansive soil slope considering the shear zone damage softening was proposed.The results show that the shear zone subjected to large displacement shear deformation exhibits an obvious damage softening phenomenon.The damage variable equation based on the logistic function can be well used to describe the shear damage characteristics of expansive soil,and the proposed shear damage model is in good agreement with the ring shear test results.The vector sum method considering the damage softening behavior of the shear zone can be well applied to analyze the stability evolution characteristics of the expansive soil slope.The stability factor of the expansive soil slope decreases with the increase of shear displacement,showing an obvious progressive failure behavior. 展开更多
关键词 Expansive soil slope Stability analysis Ring shear test Vector sum method Damage model Strain softening
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