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The recrystallization mechanism and its effects on texture in pre-twinned AZ31 magnesium alloy during medium-high temperature impact loading 认领 引用
1
作者 Xiao Liu Xiaofeng Zhang +6 位作者 Biwu Zhu Chao Xie Bibo Hu Wenhui Liu Luoxing Li Congchang Xu Pengcheng Guo 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2026年第1期459-475,共17页
Investigating effect of recrystallization mechanism on deformation mode and texture evolution is conducive to controlling deformation mechanism and texture in magnesium alloys under medium-high temperature impact load... Investigating effect of recrystallization mechanism on deformation mode and texture evolution is conducive to controlling deformation mechanism and texture in magnesium alloys under medium-high temperature impact loading.In the present study,a Johnson-Cook model incorporating twin strengthening was established to simulate macro-deformation,and a twinning induced recrystallization(TDRX)model and bulging recrystallization(GBBDRX)model are introduced into visco-plastic self consistant(VPSC)framework to quantitatively study the deformation mechanism of pre-twinned AZ31 magnesium alloy during medium-high temperature impact loading.Both TDRX and GBBDRX occur,with basal slip as the dominant slip system,followed by pyramidal〈c+a〉slip and prismatic slip.The dynamic recrystallization(DRX)significantly influences basal and pyramidal〈c+a〉slip systems,with minimal impact on secondary deformation mechanism.In addition,the recrystallization mechanism of grain boundary bowing increases the activity of basal slip and decreases the activity of pyramidal〈c+a〉slip.The nucleation and growth of recrystallized grains enhance basal slip activity and suppress pyramidal〈c+a〉slip,leading to the formation of a strong basal texture.As dynamic recrystallization progresses,a bimodal texture develops,characterized by a reduction in basal component pole density and a more pronounced basal slip. 展开更多
关键词 Az31 magnesium alloy Texture Deformation mode Dynamic recrystallization Impact loading
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Energy absorption behavior and damage constitutive model of frozen moraine soil under impact loading 认领 引用
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作者 XIE Qijun SU Lijun +1 位作者 ZHAO Bo ZHANG Fulai 《Journal of Mountain Science》 SCIE CSCD 2026年第3期1288-1301,共14页
Frozen moraine soils are widely distributed across the Tianshan Mountains,the Qinghai-Tibetan Plateau,and other high-altitude regions.Engineering activities,particularly blasting,often induce degradation of the soil m... Frozen moraine soils are widely distributed across the Tianshan Mountains,the Qinghai-Tibetan Plateau,and other high-altitude regions.Engineering activities,particularly blasting,often induce degradation of the soil microstructure,compromising its mechanical integrity and increasing the risk of slope instability and rainfall-triggered debris flows-posing serious threats to infrastructure in cold regions.Previous studies have largely treated frozen soils as homogeneous continua,thereby overlooking key micro-scale processes such as ice-soil interaction,microcrack propagation,and particle breakage.In this study,the dynamic mechanical behavior and microstructural damage mechanisms of frozen moraine soil were systematically investigated under varying temperatures(−5℃,−15℃,and−25℃)and strain rates(50 s-1,70 s-1,and 90 s-1).Results reveal that both temperature and strain rate significantly influence the dynamic stress-strain response.Energy absorption exhibits a three-stage pattern of increase,stabilization,and decline.At−25℃,increased ice brittleness reduces the peak energy absorption efficiency under impact.To capture the observed nonlinear behavior,a damage-based constitutive model was developed,incorporating coupled effects of impact-induced microcracking,ice-soil interfacial debonding,and particle fracture.The stochastic evolution of interfacial debonding and grain breakage was described using a Weibull statistical framework,linking microstructural deterioration to macroscopic response.The model shows strong agreement with experimental data and accurately simulates key parameters such as peak stress and energy absorption.These findings enhance the understanding of dynamic damage mechanisms in frozen soils and offer a computational tool for the safety assessment and hazard mitigation of engineering structures in cold,high-altitude environments. 展开更多
关键词 Frozen moraine soil Damage constitutive model Impact loading Energy absorption Ice-soil interaction Cold regions engineering
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Power Law Relationship Between Relaxation Time and Strain Rate of PBS:From Quasi-Static to Intensive Impact Loading 认领 引用
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作者 Jinhan Chen Jiliang Li +2 位作者 Tao Huang Shulin Bai Jiankang Chen 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2026年第5期654-665,共12页
In the present study,the exploration focuses on the relationship between relaxation time and strain rate in polymer-bonded sugar(PBS).This investigation encompasses a wide range of strain rates varying from 10−5s^(... In the present study,the exploration focuses on the relationship between relaxation time and strain rate in polymer-bonded sugar(PBS).This investigation encompasses a wide range of strain rates varying from 10−5s−1to 105s−1,covering 11 orders of magnitude from quasi-static to intensive impact loading.Stress and strain curves of the material were acquired through quasi-static compression,Split-Hopkinson Pressure Bar(SHPB),and first-stage light gas gun experiments at various loading speeds.These curves exhibit a noticeable correlation with strain rate,suggesting the presence of a viscosity effect on the material.The Maxwell model is employed to characterize the stress-strain curves.The findings verify that the strain rate dependence of relaxation time follows a power law relationship across static loading to intensive impact conditions. 展开更多
关键词 Impact loading Relaxation time Strain rate effect Power law Viscous effect
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ESL-Based MMC Topology Optimization of Thin-Walled Stiffened Structures Under Transient Impact Loading 认领 引用
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作者 Zizhen Guo Gang Chen +2 位作者 Ang Li Xue Bai Weisheng Zhang 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2026年第5期635-653,共19页
This paper presents an explicit topology optimization method based on the equivalent static load(ESL)method for nonlinear topology optimization of thin-walled stiffened structures under impact loading.This method defi... This paper presents an explicit topology optimization method based on the equivalent static load(ESL)method for nonlinear topology optimization of thin-walled stiffened structures under impact loading.This method defines stiffeners as moving morphable components within a Lagrangian geometric framework.By parametrizing geometric characteristics(including reinforcement positions,profiles,and sizes),it enables simultaneous optimization of both topology configurations and geometric layouts.For nonlinear dynamic optimization under impact loads,the ESL method is integrated into the explicit topology optimization framework.Through load equivalence transformation strategy,the complex nonlinear dynamic optimization problem is converted into a series of linear static subproblems,which significantly reduces computational complexity for the design of thin-walled stiffened structures under nonlinear conditions.The proposed method yields optimized design with guaranteed structural dynamic performance with enhanced optimization efficiency.Several numerical examples are presented to demonstrate its effectiveness and engineering applicability. 展开更多
关键词 Thin-walled stiffened structures Impact loading Nonlinear topology optimization Moving morphable component(MMC) Equivalent static load(ESL)
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Pull-out capacity and energy absorption of cable bolts under impact loading 认领 引用
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作者 Adel Mottahedi Naj Aziz +1 位作者 Alex Remennikov Ali Mirzaghorbanali 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2026年第1期23-42,共20页
This study investigates the performance of high-strength cable bolts under impact loading conditions representative of rock bursts in underground environments.Although widely used,the dynamic behaviour of these cable ... This study investigates the performance of high-strength cable bolts under impact loading conditions representative of rock bursts in underground environments.Although widely used,the dynamic behaviour of these cable bolts has received limited experimental attention,and their effectiveness in seismically active zones remains a subject of ongoing debate.To address this gap,a reverse pull-out test machine integrated with a drop hammer rig was employed.Tests were conducted on 70-t SUMO bulbed and non-bulbed cable bolts with encapsulation lengths of 300 and 450 mm,subjected to an impact energy of 14.52 k J.Results indicate that non-bulbed cables,despite showing lower initial peak loads(average 218 vs.328 k N for bulbed cables at 300 mm encapsulation),demonstrated superior energy absorption(average 11.26 vs.8.75 k J)and displacement capacity(average 48.40 vs.36.25 mm).Increasing the encapsulation length for bulbed cables led to a reduction in initial peak load but improved displacement and energy absorption.The dominant failure mechanism was debonding at the cable-grout interface,characterised by frictional sliding and cable rotation.These findings provide new insights into the energy dissipation mechanisms of cables and support the development of more resilient ground support systems for dynamically active conditions. 展开更多
关键词 Rock reinforcement Cable bolt Impact loading Pull-out testing Mine seismicity Rock burst
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Failure mechanisms of electronic detonators subjected to high impact loading in rock drilling and blasting 认领 引用 被引量：2
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作者 Zhendong Leng Yong Fan +2 位作者 Wenbo Lu Qidong Gao Guangdong Yang 《International Journal of Coal Science & Technology》 SCIE EI CAS CSCD 2025年第1期214-227,共14页
In rock drilling and blasting,the misfire of electronic detonators will not only affect the rock fragmentation result but also bring serious potential safety hazards to engineering construction.An accurate and compreh... In rock drilling and blasting,the misfire of electronic detonators will not only affect the rock fragmentation result but also bring serious potential safety hazards to engineering construction.An accurate and comprehensive understanding of the failure mechanisms of electronic detonators subjected to impact loading is of great significance to the reliability design and field safety use of electronic detonators.The spatial distribution characteristics and failure modes of misfired electronic detonators under different application scenarios are statistically analysed.The results show that under high impact loads,electronic detonators will experience failure phenomena such as rupture of the fuse head,fracture of the bridge wire,falling off of the solder joint,chip module damage and insufficient initiation energy after deformation.The lack of impact resistance is the primary cause of misfire of electronic detonators.Combined with the underwater impact resistance test and the impact load test in the adjacent blasthole on site,the formulas of the impact failure probability of the electronic detonator under different stress‒strength distribution curves are deduced.The test and evaluation method of the impact resistance of electronic detonators based on stress‒strength interference theory is proposed.Furthermore,the impact failure model of electronic detonators considering the strength degradation effect under repeated random loads is established.On this basis,the failure mechanism of electronic detonators under different application environments,such as open-pit blasting and underground blasting,is revealed,which provides scientific theory and methods for the reliability analysis,design and type selection of electronic detonators in rock drilling and blasting. 展开更多
关键词 Rock blasting Electronic detonator Impact loading Stress‒strength interference theory Strength degradation effect
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Dynamic response of polymethacrylimide foam sandwich structures with different core layers under water impact loading 认领 引用
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作者 Peilin Zhu Jili Rong +2 位作者 Shenglong Wang Zichao Chen Zifan Jiang 《Defence Technology（防务技术）》 SCIE EI CAS CSCD 2025年第7期203-222,共20页
Polymethacrylimide(PMI)foam has the highest specific stiffness and strength among polymer foams,with excellent radar-absorbing capabilities,which provide it with broad prospects in underwater ap-plications.To evaluate... Polymethacrylimide(PMI)foam has the highest specific stiffness and strength among polymer foams,with excellent radar-absorbing capabilities,which provide it with broad prospects in underwater ap-plications.To evaluate the impact resistance of PMI foam sandwich structures,the dynamic response and energy absorption characteristics of PMI foam sandwich structures with different core layers under various water impact loads were investigated using combined experimental and numerical methods.A fluid-structure interaction device with a diffusion angle was used for water impact testing of the PMI foam sandwich structures.The 3D-DIC technique was employed to process the deformation images of the sandwich-structure back panel captured by the high-speed cameras.Numerical simulations were performed to analyze the dynamic deformation process of the PMI foam core.The results indicated that the maximum deformation of the back panel exhibited a nonlinear relationship with the impulse.Below the critical impulse,the maximum deformation of the back panel plateaued,which was determined by the core density.Beyond the critical impulse,the rate of deformation increased with the impulse was governed by the core thickness.Compared with different sandwich panels,PMI foam sandwich struc-tures demonstrate significant advantages in terms of impact resistance under high-impulse conditions. 展开更多
关键词 PMI foam sandwich structure Underwater impact loading Impact resistance Energy absorption characteristics
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Mechanical behavior and energy dissipation characteristics of coal under coupled 3D static and graded cyclic impact loading 认领 引用
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作者 Zhuoyue Sun Yongzheng Wu Junchen Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2025年第12期7980-7992,共13页
In this study,a coupled loading method combining three-dimensional static loading with graded cyclic impacts was developed to simulate the stress environment of the surrounding rock under impact ground pressure caused... In this study,a coupled loading method combining three-dimensional static loading with graded cyclic impacts was developed to simulate the stress environment of the surrounding rock under impact ground pressure caused by cyclic disturbances.The mechanical behavior and energy dissipation of coal under this loading method were studied using a split Hopkinson pressure bar(SHPB).The results showed that the pre-applied cyclic low-pressure impacts deteriorated the coal sample's resistance to external loads.Under both cyclic low-pressure impacts and single high-pressure impacts,the dynamic peak stress and secant modulus decreased with increasing impact cycles,exhibiting dynamic fatigue characteristics.The dynamic secant modulus of the sample decreased by 4.14%-6.67%after each impact.The dissipated energy for coal fragmentation samples increased with the number of impacts,averaging 28%under cyclic low-pressure impacts and 29%under single high-pressure impacts.The efficiency of dissipated energy for coal fragmentation initially increased and then decreased as the wave impedance ratio between the coal sample and the bar increased,reaching a maximum of 43.3%when the ratio was 0.06.Based on the defined damage variable,the damage to coal samples from high-pressure impacts was found to be 12 times greater than that under low-pressure conditions.The degree of coal fragmentation was positively correlated with the maximum damage increment.With increasing maximum damage increment,the failure mode of the coal sample evolved from tensile failure to tensile-compressive-shear composite failure. 展开更多
关键词 Coal Mechanical behavior Energy dissipation Cyclic impact loading Damage characteristics
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The Failure Analysis of Carbon Fiber-Reinforced Epoxy Composites against Impact Loading with Numerical and Experimental Investigations 认领 引用 被引量：1
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作者 Md Salah Uddin 《Journal of Polymer Materials》 SCIE CAS 2025年第4期1051-1073,共23页
Carbon fiber-reinforced composites(CFRCs)have a wide range of applications in the aerospace,automotive,and energy sectors.A higher specific strength-to-weight ratio is desired in high-performance applications.The fail... Carbon fiber-reinforced composites(CFRCs)have a wide range of applications in the aerospace,automotive,and energy sectors.A higher specific strength-to-weight ratio is desired in high-performance applications.The failure mechanism of CFRCs involves multiscale phenomena,such as failure that can occur at the matrix,fibers,interface,layers,lamina,and laminates.When an impactor hits the CFRCs,the design involves analyzing each of these stages to prevent failure and optimize the properties of CFRCs under various loading conditions.A numerical model was employed to predict the fracture toughness of CFRCs with varying weight fractions and orientations.Finite Element Analysis(FEA)was conducted at the fiber level on a micrometer scale for the CFRCs against an impact loading.Epoxy composite samples at the coupon level were prepared using the hand layup technique with carbon fibers laid at three different angles,i.e.,longitudinal,transverse,and angular orientations.Samples with five different weight percentages of carbon fibers were prepared and investigated.An Izod impact tester was used to fracture the samples and characterize the energy absorption.The fractured surfaces were observed with a scanning electron microscope(SEM).The numerical and experimental results show that crack propagation is inhibited at higher loading fractions at an angular orientation by creating obstacles for the crack to propagate and arresting the dislocation motion.The fractography analysis through a scanning electron microscope exhibits how the angular orientations of the fibers are reoriented after fracture to prevent further crack propagation. 展开更多
关键词 Impact loading failure analysis carbon fiber epoxy composites crack inhibition fractography and orientations
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Effect of roughness on the shear behavior of rock joints subjected to impact loading 认领 引用 被引量：11
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作者 Feili Wang Shuhong Wang +3 位作者 Wei Yao Xing Li Fanzheng Meng Kaiwen Xia 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第2期339-349,共11页
The shear behavior is regarded as the dominant property of rock joints and is dramatically affected by the joint surface roughness.To date,the effect of surface roughness on the shear behavior of rock joints under sta... The shear behavior is regarded as the dominant property of rock joints and is dramatically affected by the joint surface roughness.To date,the effect of surface roughness on the shear behavior of rock joints under static or cyclic loading conditions has been extensively studied,but such effect under impact loading conditions keeps unclear.To address this issue,a series of impact shear tests was performed using a novel-designed dynamic experimental system combined with the digital image correlation(DIC)technique.The dynamic shear strength,deformability and failure mode of the jointed specimens with various joint roughness coefficients(JRC)are comprehensively analyzed.Results show that the shear strength and shear displacement characteristics of the rock joint under the impact loading keep consistent with those under static loading conditions.However,the temporal variations of shear stress,slip displacement and normal displacement under the impact loading conditions show obviously different behaviors.An elastic rebound of the slip displacement occurs during the impact shearing and its value increases with increasing joint roughness.Two identifiable stages(i.e.compression and dilation)are observed in the normal displacement curves for the rougher rock joints,whereas the joints with small roughness only manifest normal compression displacement.Besides,as the roughness increases,the maximum compression tends to decrease,while the maximum dilation gradually increases.More-over,the microstructural analysis based on scanning electron microscope(SEM)suggests that the roughness significantly affects the characteristics of the shear fractured zone enclosing the joint surface. 展开更多
关键词 Rock joint Impact loading Joint roughness Shear strength Shear deformability
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Unveiling the mechanical response and accommodation mechanism of pre-rolled AZ31 magnesium alloy under high-speed impact loading 认领 引用 被引量：12
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作者 Xiao Liu Hui Yang +3 位作者 Biwu Zhu Yuanzhi Wu Wenhui Liu Changping Tang 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2022年第4期1096-1108,共13页
Split Hopkinson pressure bar(SHPB)tests were conducted on pre-rolled AZ31 magnesium alloy at 150–350℃ with strain rates of 2150s-1,3430s-1 and 4160s-1.The mechanical response,microstructural evolution and accommo... Split Hopkinson pressure bar(SHPB)tests were conducted on pre-rolled AZ31 magnesium alloy at 150–350℃ with strain rates of 2150s-1,3430s-1 and 4160s-1.The mechanical response,microstructural evolution and accommodation mechanism of the pre-rolled AZ31 magnesium alloy under high-speed impact loading were investigated.The twin and shear band are prevailing at low temperature,and the coexistence of twins and recrystallized grains is the dominant microstructure at medium temperature,while at high temperature,dynamic recrystallization(DRX)is almost complete.The increment of temperature reduces the critical condition difference between twinning and DRX,and the recrystallized temperature decreases with increasing strain rate.The mechanical response is related to the competition among the shear band strengthen,the twin strengthen and the fine grain strengthen and determined by the prevailing grain structure.The fine grain strengthen could compensate soften caused by the temperature increase and the reduction of twin and shear band.During high-speed deformation,different twin variants,introduced by pre-rolling,induce different deformation mechanism to accommodate plastic deformation and are in favor for non-basal slip.At low temperature,the high-speed deformation is achieved by twinning,dislocation slip and the following deformation shear band at different deformation stages.At high temperature,the high-speed deformation is realized by twinning and dislocation slip of early deformation stage,transition shear band of medium deformation stage and DRX of final deformation stage. 展开更多
关键词 Mechanical response Pre-twinning Accommodation mechanism Pre-rolled AZ31 magnesium alloy High-speed impact loading
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Long-term mechanical behavior and characteristics of cemented tailings backfill through impact loading 认领 引用 被引量：12
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作者 Yu-ye Tan Elmo Davide +2 位作者 Yu-cheng Zhou Wei-dong Song Xiang Meng 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2020年第2期140-151,共12页
Cemented tailings backfill(CTB)structures are important components of underground mine stopes.It is important to investigate the characteristics and dynamic behavior of CTB materials because they are susceptible to di... Cemented tailings backfill(CTB)structures are important components of underground mine stopes.It is important to investigate the characteristics and dynamic behavior of CTB materials because they are susceptible to disturbance by dynamic loading,such as excavation and blasting.In this study,the authors present the results of a series of Split-Hopkinson pressure bar(SHPB)single and cyclic impact loading tests on CTB specimens to investigate the long-term dynamic mechanical properties of CTB.The stress-strain relationship,dynamic strength,and dynamic failure characteristics of CTB specimens are analyzed and discussed to provide valuable conclusions that will improve our knowledge of CTB long-term mechanical behavior and characteristics.For instance,the dynamic peak stress under cyclic impact loading is approximately twice that under single impact loading,and the CTB specimens are less prone to fracture when cyclically loaded.These findings and conclusions can provide a new set of references for the stability analysis of CTB materials and help guide mine designers in reducing the amount of binding agents and the associated mining cost. 展开更多
关键词 cyclic impact loading cemented tailings backfill dynamic mechanical properties Split–Hopkinson pressure bar dynamic peak stress
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Responses of jointed rock masses subjected to impact loading 认领 引用 被引量：13
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作者 Shabnam Aziznejad Kamran Esmaieli +1 位作者 John Hadjigeorgiou Denis Labrie 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2018年第4期624-634,共11页
Impact-induced damage to jointed rock masses has important consequences in various mining and civil engineering applications. This paper reports a numerical investigation to address the responses of jointed rock masse... Impact-induced damage to jointed rock masses has important consequences in various mining and civil engineering applications. This paper reports a numerical investigation to address the responses of jointed rock masses subjected to impact loading. It also focuses on the static and dynamic properties of an intact rock derived from a series of laboratory tests on meta-sandstone samples from a quarry in Nova Scotia, Canada. A distinct element code(PFC2D) was used to generate a bonded particle model(BPM) to simulate both the static and dynamic properties of the intact rock. The calibrated BPM was then used to construct large-scale jointed rock mass samples by incorporating discrete joint networks of multiple joint intensities into the intact rock matrix represented by the BPM. Finally, the impact-induced damage inflicted by a rigid projectile particle on the jointed rock mass samples was determined through the use of the numerical model. The simulation results show that joints play an important role in the impactinduced rock mass damage where higher joint intensity results in more damage to the rock mass. This is mainly attributed to variations of stress wave propagation in jointed rock masses as compared to intact rock devoid of joints. 展开更多
关键词 Jointed rock mass Impact loading Microcracks Rock damage
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Crack dynamic propagation properties and arrest mechanism under impact loading 认领 引用 被引量：6
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作者 Yuqing Dong Zheming Zhu +3 位作者 Li Ren Lei Zhou Peng Ying Meng Wang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2020年第6期1171-1184,共14页
Crack dynamic propagation and arrest behaviors have received extensive attention over the years.However,there still remain many questions,e.g.under what conditions will a running crack come to arrest?In this paper,dro... Crack dynamic propagation and arrest behaviors have received extensive attention over the years.However,there still remain many questions,e.g.under what conditions will a running crack come to arrest?In this paper,drop weight impact(DWI)tests were conducted to investigate crack arrest mechanism using single cleavage triangle(SCT)rock specimens.Green sandstone was selected to prepare the SCT specimens.Dynamic stress intensity factors(DSIFs)were calculated by ABAQUS code,and the critical DSIFs were determined by crack propagation speeds and fracture time measured by crack propagation gauges(CPGs).The test results show that the critical DSIF at propagation decreases with crack propagation speed.Numerical simulation for SCT specimens under different loading waves was performed using AUTODYN code.The reflected compressive wave from the incident and transmitted plates can induce crack arrests during propagation,and the number of arrest times increases with the wave length.In order to eliminate the effect of the incident and transmitted plates,models consisting of only one SCT specimen without incident and transmitted plates were established,and the same trapezoid-shaped loading wave was applied to the SCT specimen.The results show that for the SCT specimen with transmitted boundary(analogous to an infinite plate),the trapezoid-shaped loading wave cannot induce crack arrest anymore.The numerical results can well describe the occurrence of crack arrest in the experiments. 展开更多
关键词 Crack arrest Stress wave Fracture toughness Reflected wave Impact loading
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Constitutive model for concrete subjected to impact loading 认领 引用 被引量：17
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作者 刘海峰 宁建国 《Journal of Southeast University(English Edition)》 EI CAS 2012年第1期79-84,共6页
To better design and analyze concrete structures, the mechanical properties of concrete subjected to impact loadings are investigated. Concrete is considered to be a two-phase composite made up of micro-cracks and sol... To better design and analyze concrete structures, the mechanical properties of concrete subjected to impact loadings are investigated. Concrete is considered to be a two-phase composite made up of micro-cracks and solid parts which consist of coarse aggregate particles and a cement mortar matrix. The cement mortar matrix is assumed to be elastic, homogeneous and isotropic. Based on the Moil-Tanaka concept of average stress and the Eshelby equivalent inclusion theory, a dynamic constitutive model is developed to simulate the impact responses of concrete. The impact compression experiments of concrete and cement mortar are also carried out. Experimental results show that concrete and cement mortar are rate-dependent. Under the same impact velocity, the load-carrying capacity of concrete is higher than that of cement mortar. Whereas, the maximum strain of concrete is lower than that of cement mortar. Regardless of whether it is concrete or cement mortar, with the increase in the impact velocity, the fragment size of specimens after experiment decreases. 展开更多
关键词 concrete micromechanics dynamic constitutivemodel impact loading
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Influence of desert sand on the mechanical properties of concrete subjected to impact loading 认领 引用 被引量：18
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作者 Liu Haifeng Ma Jurong +1 位作者 Wang Yiying Ning Jianguo 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2017年第6期583-595,共13页
A74-mm-diameter Split Hopkinson pressure bar was used to carry out the dynamic compression experiment of concrete made of desert sand.The dynamic failure processes of concrete different in specimen size,impact velocit... A74-mm-diameter Split Hopkinson pressure bar was used to carry out the dynamic compression experiment of concrete made of desert sand.The dynamic failure processes of concrete different in specimen size,impact velocity,desert sand replacement ratio,size and volume content of coarse aggregate were simulated.Research results showed that concrete made of desert sand had size-effect and was rate-dependent.The peak stress of concrete made of desert sand declined with the minimum size of coarse aggregate.However,the peak stress of concrete made of desert sand increased first,and then declined with the volume content and maximum size of coarse aggregate. 展开更多
关键词 Concrete Desert sand Mechanical properties Impact loading
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Reinforcing effects of polypropylene on energy absorption and fracturing of cement-based tailings backfill under impact loading 认领 引用 被引量：3
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作者 Jiajian Li Shuai Cao Erol Yilmaz 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第4期650-664,共15页
Polypropylene(PP)fiber-reinforced cement-based tailings backfill(FRCTB)is a green compound material with superior crack resistance and has good prospects for application in underground mining.However,FRCTB exhibits su... Polypropylene(PP)fiber-reinforced cement-based tailings backfill(FRCTB)is a green compound material with superior crack resistance and has good prospects for application in underground mining.However,FRCTB exhibits susceptibility to dynamic events,such as impact ground pressure and blast vibrations.This paper investigates the energy and crack distribution behavior of FRCTB under dynamic impact,considering the height/diameter(H/D)effect.Split Hopkinson pressure bar,industrial computed tomography scan,and scanning electron microscopy(SEM)experiments were carried out on six types of FRCTB.Laboratory outcomes confirmed fiber aggregation at the bottom of specimens.When H/D was less than 0.8,the proportion of PP fibers distributed along theθangle direction of80°-90°increased.For the total energy,all samples presented similar energy absorption,reflectance,and transmittance.However,a rise in H/D may cause a rise in the energy absorption rate of FRCTB during the peak phase.A positive correlation existed between the average strain rate and absorbed energy per unit volume.The increase in H/D resulted in a decreased crack volume fraction of FRCTB.When the H/D was greater than or equal to 0.7,the maximum crack volume fraction of FRCTB was observed close to the incidence plane.Radial cracks were present only in the FRCTB with an H/D ratio of 0.5.Samples with H/D ratios of 0.5 and 0.6 showed similar distributions of weakly and heavily damaged areas.PP fibers can limit the emergence and expansion of cracks by influencing their path.SEM observations revealed considerable differences in the bonding strengths between fibers and the FRCTB.Fibers that adhered particularly well to the substrate were attracted together with the hydration products adhering to surfaces.These results show that FRCTB is promising as a sustainable and green backfill for determining the design properties of mining with backfill. 展开更多
关键词 cement-based tailings fiber-reinforced backfills fracture energy absorption impact loading
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Dynamic response characteristics of dry and watersaturated schist under impact loading 认领 引用 被引量：3
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作者 ZHOU Yang SU Sheng-rui CHEN Jian-xun 《Journal of Mountain Science》 SCIE CSCD 2020年第12期3123-3136,共14页
Many geological engineering hazards are closely related to the dynamic mechanical properties of rock materials.However,most existing studies on the dynamic mechanical properties of rock materials were conducted on the... Many geological engineering hazards are closely related to the dynamic mechanical properties of rock materials.However,most existing studies on the dynamic mechanical properties of rock materials were conducted on the hard rocks such as sandstone,granite,limestone,and marble,whereas soft rocks,such as schist,are less studied.Therefore,in this study,a series of triaxial impact tests were conducted on dry and saturated schist by employing a modified triaxial split Hopkinson pressure bar system to reveal the coupling effects of water,strain rate,and triaxial confining pressure on the mechanical properties of schist.The results show that schist is a type of watersensitive rock and the stress-strain curve of saturated schist has apparent ductility.The effects of strain rate on dynamic strain,deformation modulus and peak stress were analyzed.The results also show that the dynamic peak stress is affected by the combined softening effect and viscous effect of water under impact loading.Finally,it was found that the failure mode of schist belongs to typical axial tensile failure under uniaxial impact tests,and shear failure is the main failure mode under triaxial impact tests.With the increase in confining pressure,the failure modes of schist change from tensile failure to shear failure.This research can provide useful parameters for geological engineering hazard prevention in mountain areas. 展开更多
关键词 Dry and water-saturated schist Triaxial stress constraint Modified triaxial split Hopkinson pressure bar Dynamic mechanical behavior Impact loading
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Design of Bridge Expansion Joints with Perforated Dowels Under Impact Loading 认领 引用 被引量：4
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作者 YODA Teruhiko AYASHI Mamiko 《Transactions of Tianjin University》 EI CAS 2008年第5期340-343,共4页
The expansion joints are expected to have movement capacity, bearing capacity for static and dynamic loading, water-tightness, low noise emission and traffic safety. In particular, the failure due to impact loading is... The expansion joints are expected to have movement capacity, bearing capacity for static and dynamic loading, water-tightness, low noise emission and traffic safety. In particular, the failure due to impact loading is the main reason for the observed damages. The problem of dynamic behavior of the expansion joints is so complex that we shall focus our attention on the impact factor for vehicle load that is governed by traffic impact. In order to overcome this difficulty, the cantilever-toothed aluminum joint (finger joint) is one of the promising joints under impact loading. In this study, from the viewpoint of design methodology, numerical studies for impact behavior were conducted for aluminum alloy expansion joints with perforated dowels. The design impact factor for the expansion joints with the perforated dowels against traffic impact loading was examined by using numerical simulations. 展开更多
关键词 bridge expansion joints traffic impact loading perforated dowel
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Degradation mechanism of rock under impact loadings by integrated investigation on crack and damage development 认领 引用 被引量：3
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作者 周子龙 江益辉 +1 位作者 邹洋 翁磊 《Journal of Central South University》 SCIE EI CAS 2014年第12期4646-4652,共7页
Failure of rock under impact loadings involves complex micro-fracturing and progressive damage. Strength increase and splitting failure have been observed during dynamic tests of rock materials. However, the failure m... Failure of rock under impact loadings involves complex micro-fracturing and progressive damage. Strength increase and splitting failure have been observed during dynamic tests of rock materials. However, the failure mechanism still remains unclear. In this work, based on laboratory tests, numerical simulations with the particle flow code(PFC) were carried out to reproduce the micro-fracturing process of granite specimens. Shear and tensile cracks were both recorded to investigate the failure mode of rocks under different loading conditions. At the same time, a dynamic damage model based on the Weibull distribution was established to predict the deformation and degradation behavior of specimens. It is found that micro-cracks play important roles in controlling the dynamic deformation and failure process of rock under impact loadings. The sharp increase in the number of cracks may be the reason for the strength increase of rock under high strain rates. Tensile cracks tend to be the key reason for splitting failure of specimens. Numerical simulation of crack propagation by PFC can give vivid description of the failure process. However, it is not enough for evaluation of material degradation. The dynamic damage model is able to predict the stress-strain relationship of specimens reasonably well, and can be used to explain the degradation of specimens under impact loadings at macro-scale. Crack and damage can describe material degradation at different scales and can be used together to reveal the failure mechanism of rocks. 展开更多
关键词 impact loading dynamic failure particle flow code crack damage
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