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A review of test methods for uniaxial compressive strength of rocks:Theory,apparatus and data processing 认领 引用 被引量：3
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作者 Wei-Qiang Xie Xiao-Li Liu +2 位作者 Xiao-Ping Zhang Quan-Sheng Liu En-ZhiWang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2025年第3期1889-1905,共17页
The uniaxial compressive strength(UCS)of rocks is a vital geomechanical parameter widely used for rock mass classification,stability analysis,and engineering design in rock engineering.Various UCS testing methods and ... The uniaxial compressive strength(UCS)of rocks is a vital geomechanical parameter widely used for rock mass classification,stability analysis,and engineering design in rock engineering.Various UCS testing methods and apparatuses have been proposed over the past few decades.The objective of the present study is to summarize the status and development in theories,test apparatuses,data processing of the existing testing methods for UCS measurement.It starts with elaborating the theories of these test methods.Then the test apparatus and development trends for UCS measurement are summarized,followed by a discussion on rock specimens for test apparatus,and data processing methods.Next,the method selection for UCS measurement is recommended.It reveals that the rock failure mechanism in the UCS testing methods can be divided into compression-shear,compression-tension,composite failure mode,and no obvious failure mode.The trends of these apparatuses are towards automation,digitization,precision,and multi-modal test.Two size correction methods are commonly used.One is to develop empirical correlation between the measured indices and the specimen size.The other is to use a standard specimen to calculate the size correction factor.Three to five input parameters are commonly utilized in soft computation models to predict the UCS of rocks.The selection of the test methods for the UCS measurement can be carried out according to the testing scenario and the specimen size.The engineers can gain a comprehensive understanding of the UCS testing methods and its potential developments in various rock engineering endeavors. 展开更多
关键词 Uniaxial compressive strength(UCS) UCS testing methods Test apparatus Data processing
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Synergistic reinforcement using pressure releasing and energy absorbing method under hard roof:Physical model test 认领 引用
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作者 Qi Wang Jiting Liu +3 位作者 Bei Jiang Zhenhua Jiang Yusong Deng Chuanjie Xu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2025年第9期5845-5860,共16页
During fully mechanized caving mining of thick coal seams,a large amount of strain energy accumulates in the roof,especially when the roof is thick and hard,making it difficultfor the roof to collapse naturally.When t... During fully mechanized caving mining of thick coal seams,a large amount of strain energy accumulates in the roof,especially when the roof is thick and hard,making it difficultfor the roof to collapse naturally.When the roof eventually collapses,the accumulated energy is released instantaneously,exerting a strong impact on the roadway.To address this issue,we proposed the synergistic control method of directional comprehensive pressure relief and energy-absorbing support(PREA)for roadways with hard roofs.In this study,we developed a three-dimensional physical model test apparatus for roof cutting and pressure relief.The 122108 ventilation roadway at the Caojiatan Coal Mine,which has a thick and hard roof,was taken as the engineering example.We analyzed the evolution patterns of stress and displacement in both the stope and the roadway surrounding rocks under different schemes.The PREA reinforcement mechanism for the roadway was investigated through comparative model tests between the new and original methods.The results showed that,compared to the original method,the new method reduced surrounding rock stress by up to 60.4%,and the roadway convergence decreased by up to 52.1%.Based on these results,we proposed corresponding engineering recommendations,which can guide fieldreinforcement design and application.The results demonstrate that the PREA method effectively reduces stress and ensures the safety and stability of the roadway. 展开更多
关键词 Directional comprehensive pressure relief High-strength support Three-dimensional model test Reinforcing method Synergistic control
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A new test method for friction in incremental sheet forming 认领 引用
3
作者 Guang-can YANG Da-wei ZHANG +1 位作者 Chong TIAN Sheng-dun ZHAO 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2025年第12期3985-4006,共22页
An analytical model for contact area and contact stress considering the loading history in incremental sheet forming(ISF)was established.Then,by integrating with the directional characteristics of friction force and h... An analytical model for contact area and contact stress considering the loading history in incremental sheet forming(ISF)was established.Then,by integrating with the directional characteristics of friction force and horizontal force in the process,a friction test method reflecting the forming characteristics of ISF was proposed.Friction coefficients during the forming processes of parts with different wall angles were measured under various plane curves,process paths,and lubrication conditions.Furthermore,the accuracy of the analytical model,as well as the measured friction coefficients and their variation trends,was verified through comparative analysis with experimental results,simulation data,and outcomes from other existing models.The results indicate that the influence of the plane curve characteristics and process paths of parts on the friction condition is not significant.Under the lubrication conditions of L-HM46 oil,MoS2grease,graphite powder,and dry friction,the friction coefficient shows a gradually increasing trend.Notably,when the wall angle is≤40°,the friction coefficient remains relatively constant;however,when the wall angle exceeds 40°,the friction coefficient increases progressively. 展开更多
关键词 incremental sheet forming friction test method contact area friction coefficient forming force
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Field tests on compressive bearing capacity of cast-in-situ pile and pre-bored grouted PHC pile 认领 引用
4
作者 Jiajin Zhou Rihong Zhang +2 位作者 Xiaonan Gong Jianlin Yu Tianlong Yan 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2026年第7期5759-5769,共11页
This paper presents a group of full-scale test results of cast-in-situ pile and pre-bored grouted prestressed high-strength concrete(PHC)pile(bored PHC pile)in deep soft soils.The pile shaft of castin-situ pile was ar... This paper presents a group of full-scale test results of cast-in-situ pile and pre-bored grouted prestressed high-strength concrete(PHC)pile(bored PHC pile)in deep soft soils.The pile shaft of castin-situ pile was arranged with strain sensors,and the bored PHC pile was arranged with both strain sensors and fiberoptic sensors.The side and base resistances of bored PHC pile and cast-in-situ pile were analyzed according to the fieldtest results.The research results showed that the 900 mmdiameter bored PHC pile revealed better compressive capacity compared to 1000 mm-diameter cast-insitu pile.The side resistance of bored PHC pile was also greater than that of cast-in-situ pile due to the existence of grout body.The expanding base grout body of bored PHC pile also improved its base resistance,as the base grouting process could increase base area and improve the properties of soil around pile base as well.The fieldtest results are valuable for the application of bored PHC pile and castin-situ pile in engineering practice. 展开更多
关键词 Cast-in-situ pile Bored pre-stressed high-strength concrete(PHC)pile Side resistance Base resistance Cone penetration test(CPT)method
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Energy absorption mechanism and design method of anchor cable under dynamic-static coupling condition 认领 引用
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作者 Qi Wang Jingxuan Liu +4 位作者 Mingzi Wang Bei Jiang Rugang Duan Shuo Xu Xuepeng Wang 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2026年第5期941-956,共16页
To effectively control the large deformation of the surrounding rock under complex conditions,it is often necessary to apply prestress to anchor cables.However,due to the influence of surrounding rock deformation,mini... To effectively control the large deformation of the surrounding rock under complex conditions,it is often necessary to apply prestress to anchor cables.However,due to the influence of surrounding rock deformation,mining disturbance,and strong impact,anchor cables are often in a dynamic and static coupling stress state.Therefore,it is crucial to study the dynamic and static coupling mechanical characteristics of anchor cables.Based on this,the self-developed dynamic and static coupling test equipment is developed.The dynamic and static coupling mechanical test of anchor cables is conducted.Test results indicate that the energy absorption for anchor cables under the initial load of 350 kN decreased by 69.8%compared to the condition without initial load,and the energy absorption efficiency increased by 6.6 times.The increase of initial load can improve its energy absorption efficiency,but it can also lead to a decrease in its energy absorption.The energy absorption and energy absorption efficiency shows a bilinear variation law with the increase of initial load.On this basis,the energy absorption calculation formula and the support design model of the anchor cable are established.It provides new ideas for the safety control of dynamic disasters in deep engineering. 展开更多
关键词 Anchor cable support Working load Dynamic and static coupling test Energy absorption characteristics Design method
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Bayesian parametric calibration of Shanghai deep clayey soil with CPTu data under partial drainage conditions 认领 引用
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作者 Changhong Wang Tian Fang +2 位作者 Zhaoxin Wu Kun Wang Daofei Tang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2026年第4期3003-3022,共20页
The constraint in the engineering applications of Shanghai,China,involving the deep 8th soil layer of clay,lies between drained and undrained circumstances,which impacts the stress–strain relationship of the clayey s... The constraint in the engineering applications of Shanghai,China,involving the deep 8th soil layer of clay,lies between drained and undrained circumstances,which impacts the stress–strain relationship of the clayey soil.Existing constitutive models cannot fully reflect the partial drainage mechanics,and the geotechnical parameters exhibit substantial randomness in a natural environment.Hence,it is difficult to describe the mechanical behaviors of deep clayey soil if only uniform geotechnical parameters are used.Based on the Modified Cam–Clay(MCC)model and asymptotic state theory,an enhanced constitutive model considering partial drainage is proposed.Moreover,by embedding the comprehensive model into the cylindrical cavity expansion theory,the mechanical interpretation of the piezocone penetration test(CPTu)data is derived.Combined with the in‑situ test data,key constitutive parameters are calibrated by the stochastic mechanics‑based Bayesian method.Firstly,the MCC model considering the asymptotic state is proposed.Secondly,the enhanced MCC model is combined with cylindrical cavity expansion theory to establish the mechanical transformation model between key geotechnical parameters and CPTu data.Finally,taking the extremely deep foundation pit of the Yunling comprehensive facility in Shanghai,China,as an example,the method of calibrating key geotechnical parameters is studied by the Markov Chain Monte Carlo(MCMC)algorithm.Using the calibrated parameters,the construction process of the ultra‑deep foundation pit excavation is simulated,and the numerical results are compared with the monitoring data.The results show that using CPTu data to determine the strain increment ratio can reasonably obtain the strength indices and other important constitutive parameters under partial drainage conditions.Bayesian calibration significantly reduces the randomness of geotechnical parameters,thereby providing reliable predictions for infrastructure design and construction. 展开更多
关键词 Partial drainage Constitutive model Piezocone penetration test Cylindrical cavity expansion theory Bayesian method MCMC sampling
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Model test of the collapse mode of surrounding rock induced by tunnel excavation in a karst area based on PIV 认领 引用
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作者 HUANG Fu WANG Zhi-wen +3 位作者 ZHANG Min WANG Yong-tao LUO Yue-long PAN Qiu-jing 《Journal of Central South University》 SCIE EI CAS CSCD 2026年第3期1332-1347,共16页
To analyse the collapse mode of the surrounding rock when a tunnel is excavated in a karst region,a scaled model test based on particle image velocimetry(PIV)is designed.The mix ratios of similar materials for differe... To analyse the collapse mode of the surrounding rock when a tunnel is excavated in a karst region,a scaled model test based on particle image velocimetry(PIV)is designed.The mix ratios of similar materials for different surrounding rock grades are determined via material testing.PIV is used to analyse the images of the surrounding rock deformation captured by a high-definition digital camera during the model experiment.Based on the displacement and velocity diagrams from the model experiment,the range and shape of the excavation-induced collapse of surrounding rock between the karst cave and the tunnel are obtained.Furthermore,the numerical simulation and upper bound theorem are employed to validate the results obtained from the model experiment.The good agreement of the surrounding rock collapse ranges among the model test,numerical simulation and theoretical calculation,showing that the model experiment results presented here is valid. 展开更多
关键词 concealed karst cave scaled model test similarity ratios particle image velocimetry(PIV) collapse surface limit analysis method numerical simulation
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Precision and trueness of a method for determing antimony content in groundwater using hydride generation-atomic fluorescence spectrometry 认领 引用
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作者 Bing-bing Liu Lin Zhang Ke Li 《Journal of Groundwater Science and Engineering》 2026年第1期49-58,共10页
At present,there is currently a lack of unified standard methods for the determination of antimony content in groundwater in China.The precision and trueness of related detection technologies have not yet been systema... At present,there is currently a lack of unified standard methods for the determination of antimony content in groundwater in China.The precision and trueness of related detection technologies have not yet been systematically and quantitatively evaluated,which limits the effective implementation of environmental monitoring.In response to this key technical gap,this study aimed to establish a standardized method for determining antimony in groundwater using Hydride Generation–Atomic Fluorescence Spectrometry(HG-AFS).Ten laboratories participated in inter-laboratory collaborative tests,and the statistical analysis of the test data was carried out in strict accordance with the technical specifications of GB/T 6379.2—2004 and GB/T 6379.4—2006.The consistency and outliers of the data were tested by Mandel's h and k statistics,the Grubbs test and the Cochran test,and the outliers were removed to optimize the data,thereby significantly improving the reliability and accuracy.Based on the optimized data,parameters such as the repeatability limit(r),reproducibility limit(R),and method bias value(δ)were determined,and the trueness of the method was statistically evaluated.At the same time,precision-function relationships were established,and all results met the requirements.The results show that the lower the antimony content,the lower the repeatability limit(r)and reproducibility limit(R),indicating that the measurement error mainly originates from the detection limit of the method and instrument sensitivity.Therefore,improving the instrument sensitivity and reducing the detection limit are the keys to controlling the analytical error and improving precision.This study provides reliable data support and a solid technical foundation for the establishment and evaluation of standardized methods for the determination of antimony content in groundwater. 展开更多
关键词 Mandel's h and k statistics Grubbs test Cochran test Repeatability limit Reproducibility limit Method bias value
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Non-destructive Testing of Envelope Material Based on Wave Propagation Characteristics 认领 引用
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作者 Jing Cao Bo Yuan +5 位作者 Kai Wang Jun Wu Zheng-Yang Li Yanchu Yang Dongjia Yan Peijun Wei 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2026年第1期24-35,共12页
Long-duration vehicles in near space have achieved great success;however,the non-destructive testing(NDT)methods for the envelope materials of such long-duration vehicles remain blank.In this paper,we propose the air-... Long-duration vehicles in near space have achieved great success;however,the non-destructive testing(NDT)methods for the envelope materials of such long-duration vehicles remain blank.In this paper,we propose the air-coupled ultrasonic NDT method theoretically.In the theoretical analysis process,the envelope material is simplified as an orthogonal sandwich structure.To calculate the displacement and stress fields of each medium,the state vectors are established and the transfer matrices of the material from the upper interface to the lower interface are obtained by using boundary conditions.Then,linear equations about the amplitude of reflected and transmitted waves are derived by combining the coupling boundary conditions of air and solid.The effects of incident angles,inflation of the envelope material,and debonding of the interfaces on the transmission coefficients are considered.The results show that the air-coupled ultrasonic NDT of the envelope material can be carried out in the pre-inflated state.Finally,a method for identifying interface debonding is proposed based on judging transmission coefficients within a certain frequency range. 展开更多
关键词 Envelope material Non-destructive testing Transfer matrix method Wave propagation Multilayer structure
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Three alternative filtering methods for vehicle crash data 认领 引用
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作者 Filandow E NIE Bingbing ZHOU Qing 《汽车安全与节能学报》 CAS CSCD 北大核心 2026年第2期188-199,共12页
Automotive crash test signal filtering is a key step in data processing.This study used vehicle body acceleration data and crash dummy head acceleration data obtained from vehicle crash tests to evaluate and compare t... Automotive crash test signal filtering is a key step in data processing.This study used vehicle body acceleration data and crash dummy head acceleration data obtained from vehicle crash tests to evaluate and compare three signal noise reduction techniques:the SAE J211 standard filter,the Moving Average(MA)method,and the Cumulative Integration.Based on the analysis of crash pulses and head acceleration data,the filtering results were directly correlated with body structure optimization and restraint system matching.The results show that the SAE filter provides precise frequency control,with a cutoff frequency of 100 Hz performing optimally in processing vehicle crash pulse acceleration data.The MA method,by obtaining the optimal window of data points,effectively removes noise while preserving key signal features.The Integration method reveals data trends through cumulative summation operations,naturally eliminating noise interference through summation.The SAE standard filter achieves a signal-to-noise ratio of 18.95 dB for crash pulse acceleration data and 30.49 dB for dummy head acceleration data;whereas the MA method based on 100 data points achieves corresponding signal-to-noise ratios of 8.59 dB and 13.82 dB,respectively.Additionally,directly integrating the acceleration signal yields smooth velocity and displacement curves.This study offers evidence-based guidance for the practical implementation of the three filtering methods under investigation. 展开更多
关键词 signal filtering SAE J211 Filter moving average(MA)method Cumulative Integration crash testing data
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Price composition analysis of blood glucose meters and blood glucose test strips in Hubei Province based on the World Health Organization/Health Action International standard survey method 认领 引用
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作者 Jianing Zheng Yushu Liu +2 位作者 Xi Wang Hongye Li Chenxi Liu 《Journal of Chinese Pharmaceutical Sciences》 CAS CSCD 2025年第10期954-966,共13页
The purpose of this study is to evaluate the price and composition of blood glucose meters and blood glucose test papers in Hubei Province,so as to improve the affordability of blood glucose monitoring for diabetes pa... The purpose of this study is to evaluate the price and composition of blood glucose meters and blood glucose test papers in Hubei Province,so as to improve the affordability of blood glucose monitoring for diabetes patients.Using the standard survey method jointly developed by the World Health Organization(WHO)and Health Action International(HAI)for drug price composition analysis,central level data was collected through literature review,policy review,and interviews with key informants.Field research was conducted in Wuhan and Yichang to trace price data at various levels of the supply chain.At the central level,data shows that China has implemented multiple policies related to the management and pricing of blood glucose meters and test strips,but has not yet introduced price restrictions for blood glucose meters and test strips;At the supply chain level,data shows that the price composition of blood glucose meters and test strips in Hubei Province is mainly composed of manufacturer prices and retail markups,followed by supply chain taxes and wholesale markups.It can be seen from this that China has established a comprehensive medical device registration,sales,quality control and management standard system through a series of policies.At present,China has not issued price policies for blood glucose meters and blood glucose test papers.Therefore,we can reduce product prices by including medical insurance,government subsidies,competitive bidding,and reducing supply chain taxes,thus improving the affordability of blood glucose monitoring for diabetes patients. 展开更多
关键词 WHO/HAI standard survey method Hubei province Blood glucose meters Blood glucose test strips Price composition
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Fast Charge Test Method for Battery Pack Systems with Thermal Management 认领 引用
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作者 Zidan Gong Jun Yang +1 位作者 Zhaoming Li Yuebing Feng 《Journal of Electronic Research and Application》 2025年第4期214-223,共10页
This paper introduces a kind of substitute bench testing method for vehicle application development and testing method of the test requirements,including battery fast conversion cycle test equipment,enter type incubat... This paper introduces a kind of substitute bench testing method for vehicle application development and testing method of the test requirements,including battery fast conversion cycle test equipment,enter type incubator,liquid-cooled machine and ancillary equipment composed of a set of test system,through the walk-in constant temperature box to simulate the new energy vehicles under different environmental conditions of the test requirements,Liquid-cooled machine and auxiliary parts to complete the battery thermal management system need cooling fluid conditions,the battery conversion cycle test equipment to simulate the dc fast charging way of filling pile,complete battery thermal management system test,shorten the filling fast charging time and improve battery fast charge security,for troubleshooting and data collection and analysis,Improve work efficiency,save costs,and eliminate customer anxiety about battery life and charging time. 展开更多
关键词 Thermal management battery pack system Fast-charging bench system Test method
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基于CPTU试验与SPT试验状态参数的海砂液化评价 认领 引用
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作者 张德才 《华北地震科学》 2026年第2期97-104,共8页
为解决地震岩土工程中海砂液化评估的可靠性问题,基于Seed简化法的砂土液化判别模型,结合孔压静力触探CPTU和标准贯入试验SPT两种原位测试技术的优势,开展砂土液化评价研究。通过回归分析建立CPTU试验等效纯净砂归一化锥尖阻力qc1n,cs、... 为解决地震岩土工程中海砂液化评估的可靠性问题,基于Seed简化法的砂土液化判别模型,结合孔压静力触探CPTU和标准贯入试验SPT两种原位测试技术的优势,开展砂土液化评价研究。通过回归分析建立CPTU试验等效纯净砂归一化锥尖阻力qc1n,cs、SPT试验标贯击数N63.5与砂土状态参数ψ的相关关系,实现基于状态参数的CRR预测;以江苏省某公路工程项目液化场地为工程依托,开展CPTU与SPT现场数据采集,对比两种方法的液化判别结果。研究结果表明:状态参数ψ与qt1n,cs、N63.5的相关性良好,状态参数法和Seed简化法的判别结果变化趋势基本一致且结果较为接近,但传统Seed简化法的判别结果偏保守,基于状态参数计算的CRR7.5可客观反映海砂密实度与抗液化能力,有效提高了液化判别的可靠性和准确性。 展开更多
关键词 砂土液化 CPTU试验 原位测试 SPT试验 状态参数 Seed简化法
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Research on Intelligent Non-destructive Testing Technology for Defects in Grouted Sleeves of Prefabricated Concrete Structures 认领 引用
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作者 LIU Rui 《外文科技期刊数据库（文摘版）工程技术》 2026年第7期001-005,共5页
Prefabricated construction represents a crucial direction for the green, industrialized, and intelligent transformation of the construction industry, and has experienced rapid development in recent years thanks to str... Prefabricated construction represents a crucial direction for the green, industrialized, and intelligent transformation of the construction industry, and has experienced rapid development in recent years thanks to strong national policy support. Reliable connections between prefabricated components are essential for ensuring the overall performance of prefabricated structures. Among these, reinforcement sleeve grouting connections have become one of the primary connection methods in prefabricated concrete structures due to their advantages of convenient installation, reliable load-bearing capacity, and relatively low cost. The fullness and density of the grouting material within the sleeves directly determine the effective transfer of stress along the reinforcement bars, serving as a key factor in ensuring structural integrity and seismic performance. 展开更多
关键词 Prefabricated concrete structure Grouting sleeve Defects Non-destructive testing Intelligent identification Phase-controlled array ultrasonic method
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Studying the mechanical properties of the soil-root interface using the pullout test method 认领 引用 被引量：21
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作者 JI Xiao-dong CONG Xu +2 位作者 DAI Xian-qing ZHANG Ao CHEN Li-hua 《Journal of Mountain Science》 SCIE CSCD 2018年第4期882-893,共12页
It is important to quantify the effect of the root diameter, the embedment length of the root and load speed on the soil-root interface mechanical properties for studying the root anchorage. The soilroot interface mec... It is important to quantify the effect of the root diameter, the embedment length of the root and load speed on the soil-root interface mechanical properties for studying the root anchorage. The soilroot interface mechanical properties can be obtained through the pullout force and root slippage curve(F-S curve). About 120 Pinus tabulaeformis single roots whose diameters ranged from 1 mm to 10 mm divided into 6 groups based on different root embedment length(50 mm, 100 mm and 150 mm) and different load velocity(10 mm·min-1, 50 mm·min-1, 100 mm·min-1 and 300 mm·min-1) were investigated using the pullout method. This study aims to explore the mechanical properties of the soil-root interface in the real conditions using the pullout test method. The results showed two kinds of pullout test failure modes during the experimental process: breakage failure and pullout failure. The results showed that the roots were easier to be broken when the root diameter was smaller or the loading speed was larger. The relationship between the maximum anchorage force and root diameter was linear and the linearly dependent coefficient(R^2) was larger than 0.85. The anchorage force increased with the root embedment length. An increase of 10%-15% for the maximumanchorage force was found when load speed increased from 10 to 300 mm.min-1. The mean peak slippage of the root was from 13.81 to 35.79 mm when the load velocity varied from 10 to 300 mm.min-1. The study will be helpful for the design of slopes reinforced by vegetation and in predicting risk of uprooting of trees, and will have practical benefits for understanding the mechanism of landslide. 展开更多
关键词 Mechanical properties Soil-root interface Pullout test method Anchorage force Load speed Pinus tabulaeformis
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Trajectory and attitude deviations for internal store separation due to unsteady and quasi-steady test method 认领 引用 被引量：6
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作者 Wei SONG Jingang DONG +1 位作者 Wei LU Zenghui JIANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2022年第2期74-81,共8页
The deviations of trajectory and attitude angle for internal store separation are evaluated by two wind tunnel test methods.One is the Freedrop Test(FDT),which is known as unsteady and time-dependent method of scaled ... The deviations of trajectory and attitude angle for internal store separation are evaluated by two wind tunnel test methods.One is the Freedrop Test(FDT),which is known as unsteady and time-dependent method of scaled model.The other is the Captive Trajectory System(CTS)test,which is usually regarded as a quasi-steady and time-averaged test technology.The result shows that there is a streamwise adverse pressure gradient on the cavity resulting in a nose-up pitching moment coefficient(>0)acting on the store model.When the initial pitch angular velocity is 0,the store exits the shear-layer with a nose-up pitch attitude causing the store to climb back towards and collide with the aircraft.However,the store passes through the shear-layer into the freestream with a nose-down pitch,which causes a successful separation event when the initial pitch angular velocity<0.The pitch angle obtained by unsteady test method is different from that by quasisteady test method.The time-dependent test includes the aerodynamic force induced by pitch angular velocity whereas the time-averaged method(CTS)cannot reflect the effect of unsteady aerodynamic force.The deviation of vertical displacement is not obvious for FDT and CTS test since the store has an initial vertical velocity,which is dominant for the vertical displacement.This means that the highly unsteady flow can create unpredictability in aerodynamic pitching moment of the store,which can lead to the deviation of pitch angle for internal store separation. 展开更多
关键词 Captive trajectory system Freedrop test Internal weapons Store separation Unsteady test method
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Microstructure modeling and virtual test of asphalt mixture based on three-dimensional discrete element method 认领 引用 被引量：5
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作者 马涛 张德育 +2 位作者 张垚 赵永利 黄晓明 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第6期1525-1534,共10页
The objective of this work is to model the microstructure of asphalt mixture and build virtual test for asphalt mixture by using Particle Flow Code in three dimensions(PFC3D)based on three-dimensional discrete elem... The objective of this work is to model the microstructure of asphalt mixture and build virtual test for asphalt mixture by using Particle Flow Code in three dimensions(PFC3D)based on three-dimensional discrete element method.A randomly generating algorithm was proposed to capture the three-dimensional irregular shape of coarse aggregate.And then,modeling algorithm and method for graded aggregates were built.Based on the combination of modeling of coarse aggregates,asphalt mastic and air voids,three-dimensional virtual sample of asphalt mixture was modeled by using PFC3D.Virtual tests for penetration test of aggregate and uniaxial creep test of asphalt mixture were built and conducted by using PFC3D.By comparison of the testing results between virtual tests and actual laboratory tests,the validity of the microstructure modeling and virtual test built in this study was verified.Additionally,compared with laboratory test,the virtual test is easier to conduct and has less variability.It is proved that microstructure modeling and virtual test based on three-dimensional discrete element method is a promising way to conduct research of asphalt mixture. 展开更多
关键词 asphalt mixture microstructure modeling virtual test discrete element method three-dimensional method
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Correlation method estimation of the modulation signal in the weak equivalence principle test 认领 引用 被引量：2
18
作者 Jie Luo Liang-Cheng Shen +2 位作者 Cheng-Gang Shao Qi Liu Hui-Jie Zhang 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第8期136-142,共7页
In a test of the weak equivalence principle （WEP） with a rotating torsion pendulum, it is important to estimate the amplitude of the modulation signal with high precision. We use a torsional filter to remove the fre... In a test of the weak equivalence principle （WEP） with a rotating torsion pendulum, it is important to estimate the amplitude of the modulation signal with high precision. We use a torsional filter to remove the free oscillation signal and employ the correlation method to estimate the amplitude of the modulation signal. The data analysis of an experiment shows that the uncertainties of amplitude components of the modulation signal obtained by the correlation method are in agreement with those due to white noise. The power spectral density of the modulation signal obtained by the correlation method is about one order higher than the thermal noise limit. It indicates that the correlation method is an effective way to estimate the amplitude of the modulation signal and it is instructive to conduct a high-accuracy WEP test. 展开更多
关键词 weak equivalence principle test correlation method amplitude estimation thermal noise limit
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A review of welding residual stress test methods 认领 引用 被引量：9
19
作者 Gan Shiming Liu Huaying +1 位作者 Zhai Zhiping Han Yongquan 《China Welding》 CAS 2022年第2期45-55,共11页
Due to local uneven heating during the welding process,the residual stress of the structure after welding affects the reliability of it.In order to ensure the reliability,it is of great significance to test the residu... Due to local uneven heating during the welding process,the residual stress of the structure after welding affects the reliability of it.In order to ensure the reliability,it is of great significance to test the residual stress distribution of the welded joint.It has always been the focus to find a simple and feasible method for residual stress testing to quickly and accurately obtain the residual stress distribution of welded joints.The mechanical measurement method has high measurement accuracy,convenient and easy operation,but it will cause certain damage to the components.Physical measurement method can avoid damage to components,but its test cost is usually high,and its measurement accuracy can also be affected by the material microstructure characteristics of welded components.Based on the advantages and disadvantages of these two residual stress test methods,a modal test method is proposed.This method is a non-destructive measurement method.Based on the mathematical relationship between the residual stress of the welded structure and the natural frequency(mathematical model),the natural frequency is measured through the modal test to calculate the residual stress quickly.However,it is difficult to establish a mathematical model with this method,and it is not suitable for realization. 展开更多
关键词 welding residual stress mechanical measurement method physical measurement method modal test method
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Testing method of rock structural plane using digital drilling 认领 引用 被引量：6
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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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