期刊文献+
共找到4,342篇文章
< 1 2 218 >
每页显示 20 50 100
Calibration of anisotropic yield function by introducing plane strain test instead of equi-biaxial tensile test 被引量:2
1
作者 Jie ZHU Shang-yu HUANG +2 位作者 Wei LIU Jian-hua HU Xi-fan ZOU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第11期2308-2314,共7页
The equi-biaxial tensile test is often required for parameter identification of anisotropic yield function and it demands thespecial testing technique or device. Instead of the equi-biaxial tensile test, the plane str... The equi-biaxial tensile test is often required for parameter identification of anisotropic yield function and it demands thespecial testing technique or device. Instead of the equi-biaxial tensile test, the plane strain test carried out with the traditional uniaxialtesting machine is suggested to provide the experimental data for calibration of anisotropic yield function. This simplified method byusing plane strain test was adopted to identify the parameters of Yld2000-2d yield function for 5xxx aluminum alloy and AlMgSialloy sheets. The predicted results of yield stresses, anisotropic coefficients and yield loci by the proposed method were very similarwith the experimental data and those by the equi-biaxial tensile test. It is validated that the plane strain test is effective to provideexperimental data instead of equi-biaxial tensile test for calibration of Yld2000-2d yield function. 展开更多
关键词 aluminum alloy sheet anisotropic behavior yield function parameter identification plane strain test
下载PDF
High-frequency interference waves in low strain dynamic testing of X-section concrete piles 被引量:1
2
作者 Qu Liming Fan Yuming +2 位作者 Ding Xuanming Yang Changwei Zhang Yanling 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2021年第4期877-885,共9页
Stress waves propagate along vertical,radial and circumferential directions when a non-uniformly distributed load is applied at one end of a three-dimensional shaft.As a result,the receiving signals are usually mixed ... Stress waves propagate along vertical,radial and circumferential directions when a non-uniformly distributed load is applied at one end of a three-dimensional shaft.As a result,the receiving signals are usually mixed with undesired interference components,often featuring as high-frequency fluctuations.Previous studies have revealed that sectional geometry(shape and size)greatly affects the high-frequency interference.In this study,low strain dynamic testing on full-scale X-section concrete is conducted in order to investigate the influences of high-frequency interference on velocity responses at the pile head.Emphasis is placed on the frequency and peak value of interference waves at various receiving points.Additionally,the effects of the geometrical,and mechanical properties of the pile shaft on high-frequency interference are elaborated on through the three-dimensional finite element method.The results show that the measured wave is obscured by interference waves superposed by two types of high-frequency components.The modulus and cross-sectional area are contributing factors to the frequency and peak value of the interference waves.On the other hand,the position with the least interference is determined,to some extent,by the accurate shape of the X-section. 展开更多
关键词 low strain dynamic testing X-section concrete pile high-frequency interference full-scale model test finite element method
下载PDF
Experimental Investigation on the Dynamics of Pipes Conveying Fluid Based on Strain Gauge Test 被引量:1
3
作者 Yunlong Zhao Chidong Che Yong Zhou 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2017年第3期50-56,共7页
Dynamical performance of pipes conveying fluid on board is of great importance to the reliability of machinery.The dynamic equation of a simply supported wet pipe conveying fluid is presented,taking structural damping... Dynamical performance of pipes conveying fluid on board is of great importance to the reliability of machinery.The dynamic equation of a simply supported wet pipe conveying fluid is presented,taking structural damping of the pipe and viscidity of the fluid into consideration.And the equation is also solved by using Galerkin's method.Modal identifications based on strain gauge test are carried out on both dry pipes(without fluid in it) and wet pipes(pipes conveying fluid).It is concluded from the comparison of the results that both natural frequency and the damping ratio decrease as the pipe filled with fluid,but the mode shapes vary little.Variation of equivalent damping factor is also tested.Experimental results reveal that the equivalent damping factor of fluid and the damping ratio depend greatly on the initial deformation,and fluid induced damping decreases the universal damping ratio of the pipes conveying fluid. 展开更多
关键词 PIPE CONVEYING fluid MODAL identification strain GAUGE test DAMPING ratio
下载PDF
Deformation behaviour in advanced heat resistant materials during slow strain rate testing at elevated temperature
4
作者 Mattias Calmunger Guocai Chai +1 位作者 Sten Johansson Johan Moverare 《Theoretical & Applied Mechanics Letters》 CAS 2014年第4期20-25,共6页
In this study, slow strain rate tensile testing at elevated temperature is used to evaluate the influence of temperature and strain rate on deformation behaviour in two different austenitic alloys. One austenitic stai... In this study, slow strain rate tensile testing at elevated temperature is used to evaluate the influence of temperature and strain rate on deformation behaviour in two different austenitic alloys. One austenitic stainless steel (AISI 316L) and one nickel-base alloy (Alloy 617) have been investigated. Scanning electron microscopy related techniques as electron channelling contrast imaging and electron backscattering diffraction have been used to study the damage and fracture micromechanisms. For both alloys the dominante damage micromech- anisms are slip bands and planar slip interacting with grain bounderies or precipitates causing strain concentrations. The dominante fracture micromechanism when using a slow strain rate at elevated temperature, is microcracks at grain bounderies due to grain boundery embrittlement caused by precipitates. The decrease in strain rate seems to have a small influence on dynamic strain ageing at 650℃. 展开更多
关键词 dynamic strain ageing slow strain rate tensile testing FRACTURE DAMAGE
下载PDF
Advanced test methods of material property characterization:high strain-rate testing and experimental simulation of multiaxial stress states
5
作者 Reinhard BARDENHEIER 《Baosteel Technical Research》 CAS 2010年第S1期122-,共1页
Optimum utilization of the loading capability of engineering materials is an important and active contribution to protect nature's limited resources,and it is the key for economic design methods.In order to make u... Optimum utilization of the loading capability of engineering materials is an important and active contribution to protect nature's limited resources,and it is the key for economic design methods.In order to make use of the materials' resources,those must be known very well;but conventional test methods will offer only limited informational value.The range of questions raised is as wide as the application of engineering materials,and partially they are very specific.The development of huge computer powers enables numeric modelling to simulate structural behaviour in rather complex loading environments-so the real material behaviour is known under the given loading conditions.Here the art of material testing design starts.To study the material behaviour under very distinct and specific loading conditions makes it necessary to simulate different temperature ranges,loading speeds, environments etc.and mostly there doesn't exist any commonly agreed test standard.In this contribution two popular,non-standard test procedures and test systems will be discussed on the base of their application background,special design features as well as test results and typically gained information:The demand for highspeed tests up to 1000 s^(-1) of strain rate is very specific and originates primarily in the automotive industry and the answers enable CAE analysis of crashworthiness of vehicle structures under crash conditions.The information on the material behaviour under multiaxial loading conditions is a more general one.Multiaxial stress states can be reduced to an equivalent stress,which allows the evaluation of the material's constraint and criticality of stress state.Both discussed examples shall show that the open dialogue between the user and the producer of testing machines allows custom-tailored test solutions. 展开更多
关键词 economic design numeric modelling simulation high strain-rate testing strain- rate sensitivity CRASHWORTHINESS multiaxial stress state material constraint equivalent stress state
下载PDF
Effect of Specimen Geometry on the Plane Strain Mechanism of the Uniaxial Tensile Testing of the C-Mn Steel
6
作者 Richard Alfonso Mangaraja Napitupulu Bagus Hendero Pramono +1 位作者 Dedi Priadi Eddy Sumarno Siradj 《材料科学与工程(中英文A版)》 2011年第5X期639-647,共9页
关键词 单轴拉伸试验 几何形状 平面应变 应变机制 试样 MN 塑性变形机制 测试
下载PDF
Development of a Test Rig for Axial Strains Measurement in Automobile Wheel
7
作者 Samuel Onoriode Igbudu David Abimbola Fadare 《Open Journal of Applied Sciences》 2023年第10期1764-1777,共14页
In automobile wheel application, a test rig is vital and used to simulate conditions of the wheel in service in order to affirm the safety and reliability of the wheel. The present work designed a test rig for measuri... In automobile wheel application, a test rig is vital and used to simulate conditions of the wheel in service in order to affirm the safety and reliability of the wheel. The present work designed a test rig for measuring axial strains in automobile wheel. The wheel used was a five-arm wheel (6JX14H2;ET 42) and Tyre (175 × 65 R 14). Experimental (EXP) test was carried out, with a radial load of 4750 N and inflation pressure of 0.3 MPa, to measure the axil strains which were converted to maximum principal strain values and, compared with data from Finite Element Analysis (FEA) using Creo-Element/Pro 5.0 at wheel’s contact angles of 90 degree (FEA 90 deg), 40 degree (FEA 40 deg) and 30.25 degree (FEA 30.25 deg), respectively. Results show that at the wheel’s point of contact with the ground, maximum principal strain values were highest at the inboard bead seat with a value of about 5.69 × 10<sup>-4</sup> mm/mm, followed by the values at the well of about 5.66 × 10<sup>-4</sup> mm/mm. The value at the outboard bead seat was least at about 2.22 × 10<sup>-4</sup> mm/mm, which was due to the presence of spikes at this location that tends to resist imposed radial loads. However, the highest mean maximum principal strain values at the locations of inboard, well and outboard, were about 2.11 × 10<sup>-4</sup> mm/mm, 3.78 × 10<sup>-4</sup> mm/mm and .99 × 10<sup>-4</sup> mm/mm, respectively. With the highest single value of about 5.69 × 10<sup>-4</sup> mm/mm, the inboard bead seat was the most strained location of the wheel. Overall results showed that all values of maximum principal strains were below the threshold value of about 1 × 10<sup>-2</sup> mm/mm. The values obtained for EXP and FEA could be said to be in close agreement when compared with the threshold value. With this in mind, the rig is recommended for use in related experimental procedures. 展开更多
关键词 test Rig strain Contact Angle Radial Load Inflation Pressure
下载PDF
Damage Identification in Beam-Type Structures Using Pseudo Strain Energy Density and Grey Relation Coefficient
8
作者 陈晓强 朱宏平 +1 位作者 张俊兵 李林 《Transactions of Tianjin University》 EI CAS 2010年第2期96-103,共8页
Based on pseudo strain energy density (PSED) and grey relation coefficient (GRC), an index is proposed to locate the damage of beam-type structures in time-domain. The genetic algorithm (GA) is utilized to identify th... Based on pseudo strain energy density (PSED) and grey relation coefficient (GRC), an index is proposed to locate the damage of beam-type structures in time-domain. The genetic algorithm (GA) is utilized to identify the structural damage severity of confirmed damaged locations. Furthermore, a systematic damage identification program based on GA is developed on MATLAB platform. ANSYS is employed to conduct the finite element analysis of complicated civil engineering structures, which is embedded with interface technique. The two-step damage identification is verified by a finite element model of Xinxingtang Highway Bridge and a laboratory beam model based on polyvinylidens fluoride (PVDF). The bridge model was constructed with 57 girder segments, and simulated with 58 measurement points. The damaged segments were located accurately by GRC index regardless of damage extents and noise levels. With stiffness reduction factors of detected segments as variables, the GA program evolved for 150 generations in 6 h and identified the damage extent with the maximum errors of 1% and 3% corresponding to the noise to signal ratios of 0 and 5%, respectively. In contrast, the common GA-based method without using GRC index evolved for 600 generations in 24 h, but failed to obtain satisfactory results. In the laboratory test, PVDF patches were used as dynamic strain sensors, and the damage locations were identified due to the fact that GRC indexes of points near damaged elements were smaller than 0.6 while those of others were larger than 0.6. The GA-based damage quantification was also consistent with the value of crack depth in the beam model. 展开更多
关键词 damage identification strain test data pseudo strain energy density grey relation coefficient genetic algorithm polyvinylidens fluoride
下载PDF
Model of rigid and elastic-plastic motion in intraplate blocks and strain status of principal blocks in Chinese mainland 被引量:6
9
作者 李延兴 黄珹 +3 位作者 胡新康 帅平 胡小工 张中伏 《Acta Seismologica Sinica(English Edition)》 EI CSCD 2001年第6期603-610,共8页
The model of rigid and elastic-plastic motion and strain in intraplate blocks is established in the paper. The unique of strain parameters and minimum root-mean-square error of velocity residual of blocks are tested i... The model of rigid and elastic-plastic motion and strain in intraplate blocks is established in the paper. The unique of strain parameters and minimum root-mean-square error of velocity residual of blocks are tested in the model. Based on the velocity fields in Chinese mainland and its peripheral areas, the strain parameters of 8 blocks are estimated and their strain status analyzed. The estimated strain status of each block is well consistent with those derived by the methods of geology and geophysics. The principal direction of collision force from India plate to Eurasia plate estimated from the azimuth of principal compressive strain of Himalaya block might be N7.1°E. 展开更多
关键词 model of block movement and strain test of model strain status of block
下载PDF
Hot deformation behavior of microstructural constituents in a duplex stainless steel during high-temperature straining 被引量:12
10
作者 Amir Momeni Shahab Kazemi Ali Bahrani 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2013年第10期953-960,共8页
The hot deformation characteristics of 1.4462 duplex stainless steel (DSS) were analyzed by considering strain partitioning between austenite and ferrite constituents. The individual behavior of ferrite and austenit... The hot deformation characteristics of 1.4462 duplex stainless steel (DSS) were analyzed by considering strain partitioning between austenite and ferrite constituents. The individual behavior of ferrite and austenite in microstructure was studied in an iso-stress condition. Hot compression tests were performed at temperatures of 800-1100~C and strain rates of 0.001-1 s-1. The flow stress was modeled by a hyperbolic sine constitutive equation, the corresponding constants and apparent activation energies were determined for the studied alloys. The constitutive equation and law of mixture were used to measure the contribution factor of each phase at any given strain. It is found that the contribution factor of ferrite exponentially declines as the Zener-HoUomon parameter (Z) increases. On the contrary, the austenite contribution polynomially increases with the increase of Z. At low Z values below 2.6. x 1015 (lnZ---35.5), a negative contribution factor is determined for austenite that is attributed to dynamic recrystallization. At high Z values, the contribution factor of austenite is about two orders of magnitude greater than that of ferrite, and therefore, austenite can accommodate more strain. Microstructural characterization via electron back-scattered diffraction (EBSD) confirms the mechanical results and shows that austenite recrystallization is possible only at high temperature and low strain rate. 展开更多
关键词 duplex stainless steel compression testing strain partitioning high temperature operations DEFORMATION
下载PDF
Effect of Temperature and Strain Rate on Dynamic Properties of Low Silicon TRIP Steel 被引量:6
11
作者 TIAN Rong LI Lin +2 位作者 B C De Cooman WEI Xi-chen SUN Peng 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2006年第3期51-56,共6页
The dynamic tensile test of 0.11C-0.62Si-1.65Mn TRIP steel was carried out at different strain rates and test temperatures. The results show that both temperature and strain rate affect the retained austenite transfor... The dynamic tensile test of 0.11C-0.62Si-1.65Mn TRIP steel was carried out at different strain rates and test temperatures. The results show that both temperature and strain rate affect the retained austenite transformation. At high strain rates, the uniform elongation decreases, whereas the total elongation and energy absorption increase. The tensile strength is less strain rate sensitive. With raising test temperature, the tensile strength is reduced and the mechanical properties generally deteriorate, especially at 110℃,However, excellent mechanical properties were obtained at 50℃ and 75℃. 展开更多
关键词 TRIP retained austenite dynamic tensile test strain rate tensile strength
下载PDF
Influence of differential settlement on pavement structure of widened roads based on large-scale model test 被引量:12
12
作者 Xiaolin Weng1,2,Wei Wang3 1 Key Laboratory for Special Area Highway Engineering of Ministry of Education,Chang’an University,Xi’an,710064,China 2 CCCC First Highway Consultants Co.,Ltd.,Xi’an,710068,China 3 Henan Vocational and Technical College of Communications,Zhengzhou,450005,China 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE 2011年第1期90-96,共7页
This study introduced at first the background of numerous highway widening projects that have been developed in recent years in China.Using a large ground settlement simulator and a fiber Bragg grating (FBG) strain se... This study introduced at first the background of numerous highway widening projects that have been developed in recent years in China.Using a large ground settlement simulator and a fiber Bragg grating (FBG) strain sensor network system,a large-scale model test,with a similarity ratio of 1:2,was performed to analyze the influence of differential settlement between new and old subgrades on pavement structure under loading condition.The result shows that excessive differential settlement can cause considerable tensile strain in the pavement structure of a widened road,for which a maximum value (S) of 6 cm is recommended.Under the repetitive load,the top layers of pavement structure are subjected to the alternate action of tensile and compressive strains,which would eventually lead to a fatigue failure of the pavement.However,application of geogrid to the splice between the new and the old roads can reduce differential settlement to a limited extent.The new subgrade of a widened road is vulnerable to the influence of dynamic load transferred from the above pavement structures.While for the old subgrade,due to its comparatively high stiffness,it can well spread the load on the pavement statically or dynamically.The test also shows that application of geogrid can effectively prevent or defer the failure of pavement structure.With geogrid,the modulus of resilience of the subgrade is increased and inhomogeneous deformation can be reduced;therefore,the stress/strain distribution in pavement structure under loading condition becomes uniform.The results obtained in this context are expected to provide a helpful reference for structural design and maintenance strategy for future highway widening projects. 展开更多
关键词 widened subgrade differential settlement fiber Bragg grating (FBG) strain sensor model test
下载PDF
Considerations of rock dilation on modeling failure and deformation of hard rocks-a case study of the mine-by test tunnel in Canada 被引量:9
13
作者 Xingguang Zhao Meifeng Cai MCai 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE 2010年第4期338-349,共12页
For the compressive stress-induced failure of tunnels at depth, rock fracturing process is often closely associated with the generation of surface parallel fractures in the initial stage, and shear failure is likely t... For the compressive stress-induced failure of tunnels at depth, rock fracturing process is often closely associated with the generation of surface parallel fractures in the initial stage, and shear failure is likely to occur in the final process during the formation of shear bands, breakouts or V-shaped notches close to the excavation boundaries. However, the perfectly elastoplastic, strain-softening and elasto-brittle-plastic models cannot reasonably describe the brittle failure of hard rock tunnels under high in-situ stress conditions. These approaches often underestimate the depth of failure and overestimate the lateral extent of failure near the excavation. Based on a practical case of the mine-by test tunnel at an underground research laboratory (URL) in Canada, the influence of rock mass dilation on the depth and extent of failure and deformation is investigated using a calibrated cohesion weakening and frictional strengthening (CWFS) model. It can be found that, when modeling brittle failure of rock masses, the calibrated CWFS model with a constant dilation angle can capture the depth and extent of stress-induced brittle failure in hard rocks at a low confinement if the stress path is correctly represented, as demonstrated by the failure shape observed in the tunnel. However, using a constant dilation angle cannot simulate the nonlinear deformation behavior near the excavation boundary accurately because the dependence of rock mass dilation on confinement and plastic shear strain is not considered. It is illustrated from the numerical simulations that the proposed plastic shear strain and confinement-dependent dilation angle model in combination with the calibrated CWFS model implemented in FLAC can reasonably reveal both rock mass failure and displacement distribution in vicinity of the excavation simultaneously. The simulation results are in good agreement with the field observations and displacement measurement data. 展开更多
关键词 hard rocks brittle failure deformation dilation angle model confinement plastic shear strain mine-by test tunnel
下载PDF
Similarity model tests of movement and deformation of coal-rock mass below stopes 被引量:6
14
作者 WANG, Haifeng CHENG, Yuanping +1 位作者 YUAN, Liang WANG, Liang 《Mining Science and Technology》 EI CAS 2010年第2期188-192,共5页
For a study of the movement and deformation of coal-rock mass and low protected seams below a stope,as well as for fracture developments and rules of evolution of permeability,we designed a plane strain model test sta... For a study of the movement and deformation of coal-rock mass and low protected seams below a stope,as well as for fracture developments and rules of evolution of permeability,we designed a plane strain model test stand to carry out model tests of similar materials in order to improve the effect of gas drainage from low protected seams and to measure the movement and deformation of coal-rock mass using a method of non-contact close-range photogrammetry.Our results show that 1) using paraffin melting to take the place of coal seam mining can satisfy the mining conditions of a protective seam;2) coal-rock mass under goafs has an upward movement after the protective seam has been mined,causing floor heaving;3) low protected seams become swollen and deformed,providing a good pressure-relief effect and causing the coal-rock mass under both sides of coal pillars to become deformed by compression and 4) the evolution of permeability of low protected seams follows the way of initial values→a slight decrease→a great increase→stability→final decrease.Simultaneously,the coefficient of air permeability increased at a decreasing rate with an increase in interlayer spacing. 展开更多
关键词 coal-rock mass below stope low protected seam plane strain similar model test
下载PDF
Use of Plastic Correction Formula to Improve Accuracy of Welding Residual Stress Test with Blind-Hole Method 被引量:3
15
作者 Qiu Zhao Kongsheng Chen +3 位作者 Meizhong Chen Bruno Briseghella Zhiyong Guo Guotao Yang 《Transactions of Tianjin University》 EI CAS 2018年第5期480-488,共9页
The blind-hole method is the most widely used approach to experimentally determine the distribution of residual stress. This paper aims to improve test accuracy of welding residual stress and conducts an experimental ... The blind-hole method is the most widely used approach to experimentally determine the distribution of residual stress. This paper aims to improve test accuracy of welding residual stress and conducts an experimental study on the strain release factors involved when using the blind-hole method for Q235 and Q345, two steels commonly used in building structures. The ranges of strain release factors A and B in the elastic stage, the effects of strain release factors on residual stress calculated values, and the plastic corrected strain release factors are analyzed considering of the effect of plastic deformation around the blind hole on measurement accuracy. Finally, a simplified calculation formula to determine strain release factors is proposed for use with the blind-hole method. Results show that in the elastic stage, strain release factor A for Q235 and Q345 ranges from-0.399 to-0.525 and strain release factor B from-0.791 to-0.960. Changing the strain release factors A and B shows that calculated residual tensile stress varies in relation to a decrease in both factor values. However, there is a increase in calculated residual compressive stress with a decrease in the strain release factor A value, but there is an decrease with a decrease in strain release factor B value. Calculated residual stress applied to elastic strain release factors is compared with that applied to amended plastic strain release factors for Q235 steel. The maximum deviation between calculated residual stress and test stress is reduced from 21.1 to 1.0%,and for Q345 steel from 26.5 to 1.2%. It is thus evident that the plastic correction formula proposed in this paper can be used in calculations when conducting a residual stress test. 展开更多
关键词 Blind-hole method WELDING RESIDUAL stress·Calibration test strain RELEASE factor PLASTIC CORRECTION
下载PDF
Constitutive Modeling for Ti-6Al-4V Alloy Machining Based on the SHPB Tests and Simulation 被引量:5
16
作者 CHEN Guang KE Zhihong +1 位作者 REN Chengzu LI Jun 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第5期962-970,共9页
A constitutive model is critical for the prediction accuracy of a metal cutting simulation. The highest strain rate involved in the cutting process can be in the range of 104-106 s 1. Flow stresses at high strain rate... A constitutive model is critical for the prediction accuracy of a metal cutting simulation. The highest strain rate involved in the cutting process can be in the range of 104-106 s 1. Flow stresses at high strain rates are close to that of cutting are difficult to test via experiments. Split Hopkinson compression bar (SHPB) technology is used to study the deformation behavior of Ti-6Al-4V alloy at strain rates of 10 -4-10 4s- 1. The Johnson Cook (JC) model was applied to characterize the flow stresses of the SHPB tests at various conditions. The parameters of the JC model are optimized by using a genetic algorithm technology. The JC plastic model and the energy density-based ductile failure criteria are adopted in the proposed SHPB finite element simulation model. The simulated flow stresses and the failure characteristics, such as the cracks along the adiabatic shear bands agree well with the experimental results. Afterwards, the SHPB simulation is used to simulate higher strain rate(approximately 3 × 10 4 s -1) conditions by minimizing the size of the specimen. The JC model parameters covering higher strain rate conditions which are close to the deformation condition in cutting were calculated based on the flow stresses obtained by using the SHPB tests (10 -4 - 10 4 s- 1) and simulation (up to 3 × 10 4 s - 1). The cutting simulation using the constitutive parameters is validated by the measured forces and chip morphology. The constitutive model and parameters for high strain rate conditions that are identical to those of cutting were obtained based on the SHPB tests and simulation. 展开更多
关键词 constitutive model Ti-6Al-4V alloy SHPB test high strain rate MACHINING
下载PDF
A Review of the Calculation Formula for the Four-component Borehole Strainmeter and Application to Earthquake Cases 被引量:2
17
作者 SU Kaizhi 《Earthquake Research in China》 CSCD 2019年第1期132-146,共15页
Based on the principle formula for the four-component strainmeters, we can directly obtain the specific plane strain, shear strain and azimuthal angle of the principal strain, and the maximum and minimum principal str... Based on the principle formula for the four-component strainmeters, we can directly obtain the specific plane strain, shear strain and azimuthal angle of the principal strain, and the maximum and minimum principal strains calculated afterwards are the indirect result. The problems of practicality of the sensitivity coefficients A and B of plane strain and shear strain are then discussed. Based on this idea, we analyzed the observation data of several four-component borehole strainmeters near the epicenter of the Yiliang M_S5.7 earthquake in 2012 and the Ludian M_S6.5 earthquake in 2014 in the Zhaotong area, Yunnan Province. The results show that the analysis based on the perspective of plane strain and shear strain has an obviously better effect than that based on the component readings, and can directly peel off the respective abnormality of the plane strain and shear strain. In addition, the correlation coefficient curves between measured data of two plane strains show significant anomalies which often occur several days before and during the earthquake. 展开更多
关键词 Four-component borehole strainmeter Ludian MS6. 5 EARTHQUAKE Yiliang MS5. 7 EARTHQUAKE Plane strain ABNORMALITY Shear strain ABNORMALITY SELF-test of data strain anomaly
下载PDF
Specimen aspect ratio and progressive field strain development of sandstone under uniaxial compression by three-dimensional digital image correlation 被引量:14
18
作者 H. Munoz A. Taheri 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2017年第4期599-610,共12页
The complete stress-strain characteristics of sandstone specimens were investigated in a series of quasistatic monotonic uniaxial compression tests.Strain patterns development during pre-and post-peak behaviours in sp... The complete stress-strain characteristics of sandstone specimens were investigated in a series of quasistatic monotonic uniaxial compression tests.Strain patterns development during pre-and post-peak behaviours in specimens with different aspect ratios was also examined.Peak stress,post-peak portion of stress-strain,brittleness,characteristics of progressive localisation and field strain patterns development were affected at different extents by specimen aspect ratio.Strain patterns of the rocks were obtained by applying three-dimensional(3D) digital image correlation(DIC) technique.Unlike conventional strain measurement using strain gauges attached to specimen,3D DIC allowed not only measuring large strains,but more importantly,mapping the development of field strain throughout the compression test,i.e.in pre-and post-peak regimes.Field strain development in the surface of rock specimen suggests that strain starts localising progressively and develops at a lower rate in pre-peak regime.However,in post-peak regime,strains increase at different rates as local deformations take place at different extents in the vicinity and outside the localised zone.The extent of localised strains together with the rate of strain localisation is associated with the increase in rate of strength degradation.Strain localisation and local inelastic unloading outside the localised zone both feature post-peak regime. 展开更多
关键词 Uniaxial compression test Aspect ratio strain patterns Digital image correlation(DIC)
下载PDF
A Strain Rate Dependent Constitutive Model for the Lower Silurian Longmaxi Formation Shale in the Fuling Gas Field of the Sichuan Basin,China 被引量:3
19
作者 HOU Zhenkun LI Xianwen +4 位作者 ZHANG Yanming LIANG Huqing GUO Ying CHENG Hanlie GAO Ruchao 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2019年第4期972-981,共10页
Shale,as a kind of brittle rock,often exhibits different nonlinear stress-strain behavior,failure and timedependent behavior under different strain rates.To capture these features,this work conducted triaxial compress... Shale,as a kind of brittle rock,often exhibits different nonlinear stress-strain behavior,failure and timedependent behavior under different strain rates.To capture these features,this work conducted triaxial compression tests under axial strain rates ranging from 5×10-6 s-1 to 1×10-3 s-1.The results show that both elastic modulus and peak strength have a positive correlation relationship with strain rates.These strain rate-dependent mechanical behaviors of shale are originated from damage growth,which is described by a damage parameter.When axial strain is the same,the damage parameter is positively correlated with strain rate.When strain rate is the same,with an increase of axial strain,the damage parameter decreases firstly from an initial value(about 0.1 to 0.2),soon reaches its minimum(about 0.1),and then increases to an asymptotic value of 0.8.Based on the experimental results,taking yield stress as the cut-off point and considering damage variable evolution,a new measure of micro-mechanical strength is proposed.Based on the Lemaitre’s equivalent strain assumption and the new measure of micro-mechanical strength,a statistical strain-rate dependent damage constitutive model for shale that couples physically meaningful model parameters was established.Numerical back-calculations of these triaxial compression tests results demonstrate the ability of the model to reproduce the primary features of the strain rate dependent mechanical behavior of shale. 展开更多
关键词 strain rates triaxial compression tests damage variable constitutive model Longmaxi Formation shale
下载PDF
Analysis of axial strain in one-dimensional loading by different models 被引量:2
20
作者 G.Aryanpour M.Farzaneh 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2010年第5期745-753,共9页
Different phenomenological equations based on plasticity, primary creep (as a viscoplastic mechanism), secondary creep (as another viscoplastic mechanism) and different combinations of these equations are presente... Different phenomenological equations based on plasticity, primary creep (as a viscoplastic mechanism), secondary creep (as another viscoplastic mechanism) and different combinations of these equations are presented and used to describe the material inelastic deformation in uniaxial test. Agreement of the models with experimental results and with the theoretical concepts and physical realities is the criterion of choosing the most appropriate formulation for uniaxial test. A model is thus proposed in which plastic deformation, primary creep and secondary creep contribute to the inelastic deformation. However, it is believed that the hardening parameter is composed of plastic and primary creep parts. Accordingly, the axial plastic strain in a uniaxial test may no longer be considered as the hardening parameter. Therefore, a proportionality concept is proposed to calculate the plastic contribution of deformation. 展开更多
关键词 Modelling Uniaxial test Plastic - Creep strain hardening - Proportionality
下载PDF
上一页 1 2 218 下一页 到第
使用帮助 返回顶部