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Present-day Upper-crustal Strain Rate Field in Southeastern Tibet and its Geodynamic Implications:Constraints from GPS Measurements with ABIC Method
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作者 YANG Shaohua PAN Jiawei +1 位作者 LI Haibing SHI Yaolin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第1期265-275,共11页
The Earth’s surface kinematics and deformation are fundamental to understanding crustal evolution.An effective research approach is to estimate regional motion field and deformation fields based on modern geodetic ne... The Earth’s surface kinematics and deformation are fundamental to understanding crustal evolution.An effective research approach is to estimate regional motion field and deformation fields based on modern geodetic networks.If the discrete observed velocity field is obtained,the velocity related fields,such as dilatation rate and maximum shear strain rate,can be estimated by applying varied mathematical approaches.This study applied Akaike's Bayesian Information Criterion(ABIC)method to calculate strain rate fields constrained by GPS observations in the southeast Tibetan Plateau.Comparison with results derived from other three methods revealed that our ABIC-derived strain rate fields were more precise.The maximum shear strain rate highlighted the Xianshuihe–Xiaojiang fault system as the main boundary for the outward migration of material in southeastern Tibet,indicating rotation of eastern Tibet material around the eastern Himalaya rather than whole extrusion along a fixed channel.Additionally,distinct dilatation rate patterns in the northeast and southwest regions of the fault system were observed.The northeast region,represented by the Longmenshan area,exhibited negative dilatational anomalies;while the southwest region,represented by the Jinsha River area north of 29°N,displayed positive dilatational anomalies.This indicates compression in the former and extension in the latter.Combined with deep geophysical observations,we believe that the upper and lower crusts of the Jinsha River area north of 29°N are in an entire expanding state,probably caused by the escape-drag effect of material.The presence of a large,low-viscosity region south of 29°N may not enable the entire escape of the crust,but instead result in a differential escape of the lower crust faster than the upper crust. 展开更多
关键词 strain rate differential escape ABIC GPS southeastern Tibet
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Spalling characteristics of high-temperature treated granitic rock at different strain rates
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作者 L.F.Fan Q.H.Yang X.L.Du 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第4期1280-1288,共9页
The dynamic spalling characteristics of rock are important for stability analysis in rock engineering.This paper presented an experimental investigation on the dynamic spalling characteristics of granite with differen... The dynamic spalling characteristics of rock are important for stability analysis in rock engineering.This paper presented an experimental investigation on the dynamic spalling characteristics of granite with different temperatures and strain rates.A series of dynamic spalling tests with different impact velocities were conducted on thermally treated granite at different temperatures.The dynamic spalling strengths of granite with different temperatures and strain rates were determined.A model was proposed to correlate the dynamic spalling strength of granite,high temperature and strain rate.The results show that the spalling strength of granite decreases with increasing temperature.Moreover,the spalling strength of granite with a higher strain rate is larger than that with a lower strain rate.The proposed model can describe the relationship among dynamic spalling strength of granite,high temperature and strain rate. 展开更多
关键词 Dynamic spalling characteristics High temperature strain rate Dynamic loading GRANITE
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Extension of Flow Behaviour and Damage Models for Cast Iron Alloys with Strain Rate Effect
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作者 Chuang Liu Dongzhi Sun +2 位作者 Xianfeng Zhang Florence Andrieux Tobias Gersterc 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第3期297-310,共14页
Cast iron alloys with low production cost and quite good mechanical properties are widely used in the automotive industry.To study the mechanical behavior of a typical ductile cast iron(GJS-450)with nodular graphite,u... Cast iron alloys with low production cost and quite good mechanical properties are widely used in the automotive industry.To study the mechanical behavior of a typical ductile cast iron(GJS-450)with nodular graphite,uni-axial quasi-static and dynamic tensile tests at strain rates of 10^(-4),1,10,100,and 250 s^(-1)were carried out.In order to investigate the influence of stress state on the deformation and fracture parameters,specimens with various geometries were used in the experiments.Stress strain curves and fracture strains of the GJS-450 alloy in the strain rate range of 10^(-4)to 250 s^(-1)were obtained.A strain rate-dependent plastic flow model was proposed to describe the mechanical behavior in the corresponding strain-rate range.The available damage model was extended to take the strain rate into account and calibrated based on the analysis of local fracture strains.Simulations with the proposed plastic flow model and the damage model were conducted to observe the deformation and fracture process.The results show that the strain rate has obviously nonlinear effects on the yield stress and fracture strain of GJS-450 alloys.The predictions with the proposed plastic flow and damage models at various strain rates agree well with the experimental results,which illustrates that the rate-dependent plastic flow and damage models can be used to describe the mechanical behavior of cast iron alloys at elevated strain rates.The proposed plastic flow and damage models can be used to describe the deformation and fracture analysis of materials with similar properties. 展开更多
关键词 Dynamic behavior of materials strain rate dependency Damage model Voce model Cast iron
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Mechanical behavior of nanorubber reinforced epoxy over a wide strain rate loading
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作者 Yinggang Miao Jianping Yin +1 位作者 Wenxuan Du Lianyang Chen 《Nano Materials Science》 EI CAS CSCD 2024年第1期106-114,共9页
Nanorubber/epoxy composites containing 0,2,6 and 10 wt%nanorubber are subjected to uniaxial compression over a wide range of strain rate from 8×10^(-4) s^(-1) to~2×10^(4) s^(-1).Unexpectedly,their strain rat... Nanorubber/epoxy composites containing 0,2,6 and 10 wt%nanorubber are subjected to uniaxial compression over a wide range of strain rate from 8×10^(-4) s^(-1) to~2×10^(4) s^(-1).Unexpectedly,their strain rate sensitivity and strain hardening index increase with increasing nanorubber content.Potential mechanisms are proposed based on numerical simulations using a unit cell model.An increase in the strain rate sensitivity with increasing nanorubber content results from the fact that the nanorubber becomes less incompressible at high strain,generating a higher hydro-static pressure.Adiabatic shear localization starts to occur in the epoxy under a strain rate of 22,000 s^(-1) when the strain exceeds 0.35.The presence of nanorubber in the epoxy reduces adiabatic shear localization by preventing it from propagating. 展开更多
关键词 strain rate strain hardening Nano rubber EPOXY Adiabatic shearing localization
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Experimental and numerical study on dynamic mechanical behaviors of shale under true triaxial compression at high strain rate
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作者 Xiaoping Zhou Linyuan Han +1 位作者 Jing Bi Yundong Shou 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第2期149-165,共17页
High-energy gas fracturing of shale is a novel,high efficacy and eco-friendly mining technique,which is a typical dynamic perturbing behavior.To effectively extract shale gas,it is important to understand the dynamic ... High-energy gas fracturing of shale is a novel,high efficacy and eco-friendly mining technique,which is a typical dynamic perturbing behavior.To effectively extract shale gas,it is important to understand the dynamic mechanical properties of shale.Dynamic experiments on shale subjected to true triaxial compression at different strain rates are first conducted in this research.The dynamic stress-strain curves,peak strain,peak stress and failure modes of shale are investigated.The results of the study indicate that the intermediate principal stress and the minor principal stress have the significant influence on the dynamic mechanical behaviors,although this effect decreases as the strain rate increases.The characteristics of compression-shear failure primarily occur in shale subjected to triaxial compression at high strain rates,which distinguishes it from the fragmentation characteristics observed in shale under dynamic uniaxial compression.Additionally,a numerical three-dimensional Split Hopkinson Pressure Bar(3D-SHPB),which is established by coupling PFC3D and FLAC3D methods,is validated to replicate the laboratory characteristics of shale.The dynamic mechanical characteristics of shale subjected to different confining stresses are systematically investigated by the coupling PFC3D and FLAC3D method.The numerical results are in good agreement with the experimental data. 展开更多
关键词 Dynamic behaviors True triaxial compression High strain rates Dynamic failure mechanism PFC3D-FLAC3D coupled method
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A novel fractal-statistical scaling model of rocks considering strain rate 被引量:1
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作者 Changtai Zhou Heping Xie +2 位作者 Zhihe Wang Tao Zhou Jianbo Zhu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第11期2831-2841,共11页
The scaling-dependent behaviors of rocks are significant to the stability and safe operation of the structures built in or on rock masses for practical engineering.Currently,many size effect models are employed to con... The scaling-dependent behaviors of rocks are significant to the stability and safe operation of the structures built in or on rock masses for practical engineering.Currently,many size effect models are employed to connect laboratory measurements at small scales and engineering applications at large scales.However,limited works consider the strain rate effect.In this study,an fractal-statistical scaling model incorporating strain rate is proposed based on a weakest-link approach,fractal theory and dynamic fracture mechanics.The proposed scaling model consists of 8 model parameters with physical meaning,i.e.rate-dependent parameter,intrinsic material parameter,dynamic strain rate,quasi-static strain rate,quasi-static fracture toughness,micro-crack size,micro-crack intensity and fractal dimension,enabling the proposed scaling model to model the scaling behaviors under different external conditions.Theoretical predictions are consistent with experimental data on red sandstone,proving the reliability and effectiveness of the proposed scaling model.Thus,the scaling behaviors of rocks under dynamic loading conditions can be captured by the proposed fractal-statistical scaling model.The sensitivity analysis indicates that the nominal strength difference becomes more obvious with a higher strain rate,larger fractal dimension,smaller micro-crack size or lower micro-crack intensity.Therefore,the proposed scaling model has the potential to capture the scaling behaviors considering the thermal effect,weathering effect,anisotropic characteristic etc.,as the proposed scaling model incorporated model parameters with physical meaning.The findings of this study are of fundamental importance to understand the scaling behaviors of rock under dynamic loading condition,and thus would facilitate the appropriate design of rock engineering. 展开更多
关键词 Size effect strain rate Uniaxial compressive strength(UCS) Dynamic fracture mechanics
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Strain Rate Effect of AE Characteristics in the Whole Process of Uniaxial Tensile of Mortar
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作者 王娜 王岩 +1 位作者 SU Yihui ZHAO Haitao 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2023年第3期547-556,共10页
We completed the uniaxial tensile test of mortar in the range of strain rate from 10^(-6)to 10^(-4)s^(-1)in the section containing softening,and carried out acoustic emission monitoring(AE)simultaneously.A series of A... We completed the uniaxial tensile test of mortar in the range of strain rate from 10^(-6)to 10^(-4)s^(-1)in the section containing softening,and carried out acoustic emission monitoring(AE)simultaneously.A series of AE parameters and spectrum analysis methods were used to identify the damage evolution process and cracking mechanism of mortar at different strain rates.The results show that,with the increase of strain rate,the peak stress and tensile elastic modulus of mortar increase obviously,and the stress level corresponding to the starting point of AE activity increases significantly as well,which indicates that the mechanical properties and AE characteristics of mortar have obvious strain rate effect.With the increase of strain rate,the cumulative AE hit decreases gradually,while the average AE hit rate increases significantly,indicating that the increase of strain rate reduces the damage degree of internal microstructure of the specimen,but the crack propagation speed increases.In the pre-peak stress stage,the average of AE ringing count and signal energy decreases with the increase of strain rate,while the average of duration increases;in the post-peak stress stage(f_(t)-30%f_(t)),the average of the three AE parameters all increase with the increase of strain rate,indicating that the strain rate effect on the damage process of mortar is different before and after peak stress,and the damage mechanism represented by different parameters is also different.In the whole process of uniaxial tensile of mortar,with the increase of strain rate,the scatter distribution of AE frequency-amplitude becomes more discrete,and the b-value shows a decreasing trend.In addition,the average level of AE peak frequency decreases with the increase of strain rate,while that of ca8 band wavelet energy spectrum coefficient increases.It is indicated that the increase of strain rate enables the crack propagation state of mortar specimen to become unstable,and the width of macrocrack increases but the proportion decreases. 展开更多
关键词 MORTAR acoustic emission uniaxial tension strain rate
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The strain rate sensitive and anisotropic behavior of rare-earth magnesium alloy ZEK100 sheet
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作者 H.Wang X.Sun +4 位作者 S.Kurukuri M.J.Worswick D.Y.Li Y.H.Peng P.D.Wu 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第3期882-891,共10页
To overcome the limitation in formability at room temperature,manufacturers have developed magnesium alloys with remarkable properties by adding rare-earth elements.The rare-earth magnesium alloys behave differently f... To overcome the limitation in formability at room temperature,manufacturers have developed magnesium alloys with remarkable properties by adding rare-earth elements.The rare-earth magnesium alloys behave differently from the conventional alloys,especially with respect to their coupled anisotropic and strain rate sensitive behavior.In the current work,such behavior of the rare-earth Mg alloy ZEK100 sheet at room temperature is investigated with the aid of the elastic viscoplastic self-consistent polycrystal plasticity model.Different strain rate sensitivities(SRSs)for various deformation modes are employed by the model to simulate the strain rate sensitive behaviors under different loading directions and loading rates.Good agreement between the experiments and simulations reveals the importance and necessity of using different SRSs for each deformation mode in hexagonal close-packed metals.Furthermore,the relative activities of each deformation mode and the texture evolution during different loadings are discussed.The anisotropic and strain rate sensitive behavior is ascribed to the various operating deformation modes with different SRSs during loading along different directions. 展开更多
关键词 Rare-earth magnesium alloy strain rate sensitivity TWINNING Crystal plasticity
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Effect of Strain Rate on Tensile Behavior of Sn-9Zn-xAg-ySb;{(x, y) = (0.2, 0.6), (0.2, 0.8), (0.6, 0.2), (0.8, 0.2)} Lead-Free Solder Alloys
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作者 Shihab Uddin Md. Abdul Gafur Mohammad Obaidur Rahman 《Materials Sciences and Applications》 CAS 2023年第4期273-283,共11页
The tensile properties of Sn-9Zn-xAg-ySb;{(x, y) = (0.2, 0.6), (0.2, 0.8), (0.6, 0.2), (0.8, 0.2)} lead-free solders were investigated. All the test samples were annealed at 150°C for 1 hour. The tests are carrie... The tensile properties of Sn-9Zn-xAg-ySb;{(x, y) = (0.2, 0.6), (0.2, 0.8), (0.6, 0.2), (0.8, 0.2)} lead-free solders were investigated. All the test samples were annealed at 150°C for 1 hour. The tests are carried out at room temperature at the strain rate of 4.17 × 10<sup>-3</sup> s<sup>-1</sup>, 20.85 × 10<sup>-3</sup> s<sup>-1</sup>, and 208.5 × 10<sup>-3</sup> s<sup>-1</sup>. It is seen that the tensile strength increases and the ductility decrease with increasing the strain rate over the investigated range. From the strain rate change test results, the strain sensitivity values are found in the range of 0.0831 to 0.1455 due to the addition of different alloying elements. 展开更多
关键词 Lead-Free Solder strain rate strain Sensitivity DUCTILITY Tensile Properties
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Strength characteristics of dry and saturated rock at different strain rates 被引量:28
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作者 周子龙 蔡鑫 +3 位作者 赵源 陈璐 熊成 李夕兵 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第7期1919-1925,共7页
The strength of rock materials is largely affected by water and loading conditions, but there are few studies on mechanical properties of saturated rocks at high strain rates. Through compressive tests on dry and satu... The strength of rock materials is largely affected by water and loading conditions, but there are few studies on mechanical properties of saturated rocks at high strain rates. Through compressive tests on dry and saturated sandstone specimens, it was found that the dynamic compressive strength of both dry and saturated sandstone specimens increased with the increase of strain rates. The saturated rock specimens showed stronger rate dependence than the dry ones. The water affecting factor (WAF), as the ratio of the strength under dry state to that under saturated state, was introduced to describe the influence of water on the compressive strength at different strain rates. The WAF under static load was close to 1.38, and decreased with the increase of strain rate. When the strain rate reached 190 s^-1, the WAF reduced to 0.98. It indicates that the compressive strength of saturated specimens can be higher than that of dry ones when the strain rate is high enough. Furthermore, the dual effects of water and strain rate on the strength of rock were discussed based on sliding crack model, which provided a good explanation for the experimental results. 展开更多
关键词 ROCK STRENGTH strain rate saturated rock
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Flow behavior and microstructure of ZK60 magnesium alloy compressed at high strain rate 被引量:5
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作者 吴远志 严红革 +3 位作者 朱素琴 陈吉华 刘安民 刘先兰 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第4期930-938,共9页
Flow behavior and microstructure of a homogenized ZK60 magnesium alloy were investigated during compression in the temperature range of 250-400 ℃ and the strain rate range of 0.1-50 s^-1. The results showed that dyna... Flow behavior and microstructure of a homogenized ZK60 magnesium alloy were investigated during compression in the temperature range of 250-400 ℃ and the strain rate range of 0.1-50 s^-1. The results showed that dynamic recrystallization (DRX) developed mainly at grain boundaries at lower strain rate (0.1-1 s^-1), while in the case of higher strain rate (10-50 s^-1), DRX occurred extensively both at twins and grain boundaries at all temperature range, especially at temperature lower than 350 ℃, which resulted in a more homogeneous microstructure than that under other deformation conditions. The DRX extent determines the hot workability of the workpiece, therefore, hot deformation at the strain rate of 10-50 s^-1 and in the temperature range of 250-350 ℃ was desirable for ZK60 alloy. Twin induced DRX during high strain rate compression included three steps. Firstly, twins with high dislocation subdivided the initial grain, then dislocation arrays subdivided the twins into subgrains, and after that DRX took place with a further increase of strain. 展开更多
关键词 ZK60 magnesium alloy high strain rate compression flow behavior MICROSTRUCTURE twin induced DRX
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Influence of strain rate on microstructure and formability of AZ31B magnesium alloy sheets 被引量:10
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作者 王利飞 黄光胜 +1 位作者 李红成 张华 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第4期916-922,共7页
The effects of strain rate on microstructure and formability of AZ31B magnesium alloy sheets were investigated through uniaxial tensile tests and hemispherical punch tests with strain rates of 10^-4, 10^-3, 10^-2, 10^... The effects of strain rate on microstructure and formability of AZ31B magnesium alloy sheets were investigated through uniaxial tensile tests and hemispherical punch tests with strain rates of 10^-4, 10^-3, 10^-2, 10^-1 s^-1 at 200℃. The results show that the volume fraction of dynamic recrystallization grains increases and the original grains are gradually replaced by recrystallization grains with the strain rate decreasing. A larger elongation and a smaller r-value are obtained at a lower strain rate, moreover the erichsen values become larger with the strain rate reducing, so the formability improves. This problem arises in part from the enhanced softening and the coordination of recrystallization grains during deformation. 展开更多
关键词 AZ31B magnesium alloy strain rate dynamic recrystallization FORMABILITY
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Molecular dynamics study on temperature and strain rate dependences of mechanical tensile properties of ultrathin nickel nanowires 被引量:3
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作者 王卫东 易成龙 樊康旗 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第11期3353-3361,共9页
Based on the EAM potential, a molecular dynamics study on the tensile properties of ultrathin nickel nanowires in the (100〉 orientation with diameters of 3.94, 4.95 and 5.99 nm was presented at different temperature... Based on the EAM potential, a molecular dynamics study on the tensile properties of ultrathin nickel nanowires in the (100〉 orientation with diameters of 3.94, 4.95 and 5.99 nm was presented at different temperatures and strain rates. The temperature and strain rate dependences of tensile properties were investigated. The simulation results show that the elastic modulus and the yield strength are gradually decreasing with the increase of temperature, while with the increase of the strain rate, the stress--strain curves fluctuate more intensely and the ultrathin nickel nanowires rupture at one smaller and smaller strain. At an ideal temperature of 0.01 K, the yield strength of the nanowires drops rapidly with the increase of strain rate, and at other temperatures the strain rate has a little influence on the elastic modulus and the yield strength. Finally, the effects of size on the tensile properties of ultrathin nickel nanowires were briefly discussed. 展开更多
关键词 ultrathin nickel nanowires temperature dependence strain rate dependence tensile properties molecular dynamics simulation
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HIGH STRAIN RATE SU PERPLASTICITY IN SiCp REINFORCED AZ31 MAGNESIUM MATRIX COMPOSITE 被引量:2
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作者 陈培生 吕庆风 +2 位作者 孙扬善 蒋建清 马爱斌 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2001年第1期17-21,共5页
Superplasticity of AZ 31 magnesium matrix composites reinforced with 10 vol% SiC(2 μm) particulate i s investigated at temperature range from 365℃ to 565℃ and strain rate from 2.0 8×10<sup>-3</sup&g... Superplasticity of AZ 31 magnesium matrix composites reinforced with 10 vol% SiC(2 μm) particulate i s investigated at temperature range from 365℃ to 565℃ and strain rate from 2.0 8×10<sup>-3</sup> to 5.21×10<sup>-1</sup> s<sup>-1</sup>. The maximum total elongation of 228 % is obtained at a strain rate of 2.08×10<sup>-1</sup> s<sup>-1</sup>. The strain rate se nsitivity exponent (m) higher than 0.3, is observed when the strain rate is high er than 10<sup>-1</sup> s<sup>-1</sup> at 525℃. Increasing the test temperature to 540℃, the maximum total elongation exceeding 195% is achieved at a higher strain rate of 5.21×10<sup>-1</sup> s<sup>-1</sup> than that at 525℃. SiC in AZ31/SiCp composite ca n fine the matrix grain size. Filament is observed on the fracture surface of th e specimens showing superplasticity. 展开更多
关键词 magnesium alloys SiC p articulate composite high strain rate and superplasticity
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Uniaxial compressive behavior of equal channel angular pressing Al at wide temperature and strain rate range 被引量:1
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作者 汤忠斌 索涛 +3 位作者 张部声 李玉龙 赵峰 范学领 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第8期2447-2452,共6页
Uniaxial compressive experiments of ultrafine-grained Al fabricated by equal channel angular pressing(ECAP) method were performed at wide temperature and strain rate range. The influence of temperature on flow stress,... Uniaxial compressive experiments of ultrafine-grained Al fabricated by equal channel angular pressing(ECAP) method were performed at wide temperature and strain rate range. The influence of temperature on flow stress, strain hardening rate and strain rate sensitivity was investigated experimentally. The results show that both the effect of temperature on flow stress and its strain rate sensitivity of ECAPed Al is much larger than those of the coarse-grained Al. The temperature sensitivity of ultrafine-grained Al is comparatively weaker than that of the coarse-grained Al. Based on the experimental results, the apparent activation volume was estimated at different temperatures and strain rates. The forest dislocation interactions is the dominant thermally activated mechanism for ECAPed Al compressed at quasi-static strain rates, while the viscous drag plays an important role at high strain rates. 展开更多
关键词 ultrafine-grained materials equal channel angular pressing AL mechanical behavior strain rate sensitivity temperature dependence activation volume
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“Abnormal transient creep” in fine-grained Al-5356 alloy observed at low strain rates by high-resolution strain measurement 被引量:1
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作者 申俊杰 Kenichi IKEDA +1 位作者 Satoshi HATA Hideharu NAKASHIMA 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第5期1209-1214,共6页
Transient creep at very low strain rates (less than 10-10 s-1) is still unclear. The traditional uniaxial creep testing is less useful due to unsatisfied resolution strain (~10-6). To study transient creep behavio... Transient creep at very low strain rates (less than 10-10 s-1) is still unclear. The traditional uniaxial creep testing is less useful due to unsatisfied resolution strain (~10-6). To study transient creep behavior at such low strain rates, a high-resolution strain measurement using the helicoid spring specimen technique was employed in a fine-grained Al-5356 alloy at temperatures ranging from 0.47Tm to 0.74Tm (Tm: melting point). To clarify transient creep mechanism at such low strain rates, transmission electron microscopy (TEM) was used in microstructure observation of crept specimens. The abnormal transient creep, high temperature strengthening at T〉Tp (Tp: the phase transformation temperature, 0.58Tm) or intermediate temperature softening at 0.4Tm〈T£Tp and double-normal type (creep curves including double work-hardening stages) at T=Tp, were firstly observed. The substructure observation in a crept specimen at T=0.58Tm and e=1×10-4 shows pile-up dislocations including many small jogs with equal interval, and dislocations emitted from grain boundaries. The b-Al3Mg2 phase dissolves under the condition of testing temperatures higher than 523 K, which causes solid-solution quantity of Mg atoms to increase. Therefore, the “abnormal transient creep” may be related to the difference of solid solution strengthening caused by phase change during the creep tests. 展开更多
关键词 Al-5356 alloy transient creep phase change low strain rate
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Strain rate sensitivity of closed cell aluminium fly ash foam 被引量:2
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作者 Manmohan DASS GOEL VASANT A.MATSAGAR +1 位作者 Anil K.GUPTA Steffen MARBURG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第4期1080-1089,共10页
With the increasing use of metal foams in various engineering applications, investigation of their dynamic behaviour under varying strain rate is necessary. Closed cell aluminium fly ash foam developed through liquid ... With the increasing use of metal foams in various engineering applications, investigation of their dynamic behaviour under varying strain rate is necessary. Closed cell aluminium fly ash foam developed through liquid metallurgy route was investigated for its stress--strain behaviour at different strain rates ranging from 700 s^-1 to 1950 s^-1. The numerical model of split Hopkinson pressure bar (SHPB) was simulated using commercially available finite element code Abaqus/Explicit. Validation of numerical simulation was carried out using available experimental and numerical results. Full scale stress--strain curves wez'e developed for various strain rates to study the effect of strain rate on compressive strength and energy absorption. The results showed that the closed cell aluminium fly ash foam is sensitive to strain rate. 展开更多
关键词 high strain rate metal foam strain rate sensitivity numerical simulation split Hopkinson pressure bar
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Strain rate-dependent high temperature compressive deformation characteristics of ultrafine-grained pure aluminum produced by ECAP
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作者 颜莹 齐跃 +1 位作者 陈立佳 李小武 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第4期966-973,共8页
To explore the effect of strain rate ε on the high temperature deformation characteristics of ultrafine-grained materials, the deformation and damage features as well as microstructures of ECAP-treated pure Al at dif... To explore the effect of strain rate ε on the high temperature deformation characteristics of ultrafine-grained materials, the deformation and damage features as well as microstructures of ECAP-treated pure Al at different temperatures T and strain ratesε were systematically studied through compression tests and microscopic observations. The increase in ε eliminates strain softening at T≤473 K, and largely enhances the yield strength and flow stress at 473?573 K. The shear deformation dominates the plastic deformation of ECAP-treated Al. Many cracks along shear bands (SBs) are formed at T≥473 K and secondary SBs basically disappear at 1×10?3 s?1; however, at 1×10?2 s?1, cracks are only observed at temperature below 473 K, and secondary SBs become clearer at T≥473 K. The microstructures of ECAP-treated Al mainly consist of sub-grains (SGs). The increase in ε inhibits the SG growth, thus leading to the increases both in yield strength and flow stress at high temperatures. 展开更多
关键词 equal channel angular pressing(ECAP) pure Al strain rate high temperature compression DEFORMATION damage microstructure
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Effect of Strain Rate on Compression Behavior of Vinyl Ester Resin Casting
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作者 XIONG Tao YANG Bin XIONG Jie XU Xian-jian ZHOU Kai MAO Ming-zhong 《材料工程》 EI CAS CSCD 北大核心 2006年第5期63-67,72,共6页
Quasi-static and high strain rate compressive experiments on vinyl ester casting were carried out by means of MTS (Material Test System) and Hopkinson bar. The behaviors of the compressed unstable and fracture of the ... Quasi-static and high strain rate compressive experiments on vinyl ester casting were carried out by means of MTS (Material Test System) and Hopkinson bar. The behaviors of the compressed unstable and fracture of the resin casting at different strain rates were investigated.The results indicate that the response behavior of the resin casting is controlled by different mechanisms at different strain rate, and some mechanical properties of vinyl ester casting are rate-dependent: the casting are destroyed in toughness model under strain rate 3.3×10 -4~6.6×10 -3/s, while the casting are destroyed in brittleness model under strain rate 950~5800/s. The yield stress, yield strain energy density are all increased with the increasing strain rates at quasi-static as well as at high strain rates. What is interesting is that the yield strain decreased with the strain rates increasing at quasi-static while increased at high strain rates. It is considered that the casting occurred forcing high elastic deformation at high strain rates. The damage of the specimens is mainly controlled by axial stress before unstable deformation, while mainly controlled by shear stress after unstable deformation, and then developed to fracture finally. This progress is rate-dependent: the development of the cracks inside the castings increased with the strain rate increasing. 展开更多
关键词 vinyl ester resin QUASI-STATIC high strain rate strain rate response and crack development
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Stress-Strain Behavior of Nylon-Carbon Composite Subjected to High Strain Rate Impact Loading
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作者 Noori Hassoon Mohammed A1-Saadi 《Journal of Energy and Power Engineering》 2015年第9期791-795,共5页
The aim of this study is to investigate the dynamic stress-strain relation for the hybrid composite (nylon +carbon). Three groups of specimens are used with different number of carbon layers. The specimens were sub... The aim of this study is to investigate the dynamic stress-strain relation for the hybrid composite (nylon +carbon). Three groups of specimens are used with different number of carbon layers. The specimens were subjected to high velocity impact with different strain rates. SHPB (split Hopkinson pressure bar) is used in this investigation. The results show that, the stress-strain relation various with the strain rate. The maximum stress and strain are proportion directly with the strain rate. Also, the results revealed that, as the number of carbon layer increased, the maximum strain decreased. 展开更多
关键词 High strain rate split Hopkinson pressure bar COMPOSITE high strain rate impact.
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