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Finite Element Simulations on Failure Behaviors of Granular Materials with Microstructures Using a Micromechanics-Based Cosserat Elastoplastic Model
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作者 Chenxi Xiu Xihua Chu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第3期2305-2338,共34页
This paper presents a micromechanics-based Cosserat continuum model for microstructured granular materials.By utilizing this model,the macroscopic constitutive parameters of granular materials with different microstru... This paper presents a micromechanics-based Cosserat continuum model for microstructured granular materials.By utilizing this model,the macroscopic constitutive parameters of granular materials with different microstructures are expressed as sums of microstructural information.The microstructures under consideration can be classified into three categories:a medium-dense microstructure,a dense microstructure consisting of one-sized particles,and a dense microstructure consisting of two-sized particles.Subsequently,the Cosserat elastoplastic model,along with its finite element formulation,is derived using the extended Drucker-Prager yield criteria.To investigate failure behaviors,numerical simulations of granular materials with different microstructures are conducted using the ABAQUS User Element(UEL)interface.It demonstrates the capacity of the proposed model to simulate the phenomena of strain-softening and strain localization.The study investigates the influence of microscopic parameters,including contact stiffness parameters and characteristic length,on the failure behaviors of granularmaterials withmicrostructures.Additionally,the study examines themesh independence of the presented model and establishes its relationship with the characteristic length.A comparison is made between finite element simulations and discrete element simulations for a medium-dense microstructure,revealing a good agreement in results during the elastic stage.Somemacroscopic parameters describing plasticity are shown to be partially related to microscopic factors such as confining pressure and size of the representative volume element. 展开更多
关键词 Granular materials MICROMECHANICS Cosserat elastoplastic model MICROSTRUCTURES failure behaviors
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Mechanical properties and failure behavior of 3D printed thermoplastic composites using continuous basalt fiber under high-volume fraction 被引量:1
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作者 Hang Zhang Wei-fu Sun 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第9期237-250,共14页
Continuous basalt fiber(CBF)is an outstanding inorganic fiber produced from nature,which has a wide range of applications in the field of armor protection of national defense military.However,the mechanical response a... Continuous basalt fiber(CBF)is an outstanding inorganic fiber produced from nature,which has a wide range of applications in the field of armor protection of national defense military.However,the mechanical response and failure mechanism of 3D printed CBF reinforced components are still not well understood.Here,the 3D printing thermoplastic composites with high volume fraction CBF have been successfully prepared by fused deposition modelling(FDM)method.The effects of fiber printing direction and polymer matrix type on the tensile and flexural properties of the 3D printed composites have been explored,and the detailed failure morphology has been characterized using scanning electron microscopy and optical microscopy.It was found that under high fiber volume fraction,3D printed CBF reinforced polyamides(PA)composites have the best ability to maintain material integrity of the composites,followed by acrylonitrile butadiene styrene(ABS)and high impact polystyrene(HIPS).Besides,the results from rule of mixtures can accurately predict the longitudinal Young’s modulus of the 3D printed specimens,but there exists a large discrepancy for the prediction of the tensile strength.The microstructure analysis shows that the failure modes of 3D printed composites mainly include fiber debonding,fiber pull-out,stress whitening and matrix cracking. 展开更多
关键词 Additive manufacturing Continuous basalt fiber failure behavior Mechanical properties Thermoplastic composites
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Dynamic compressive property and failure behavior of extruded Mg-Gd-Y alloy under high temperatures and high strain rates 被引量:9
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作者 Jin-cheng Yu Zheng Liu +1 位作者 Yang Dong Zhi Wang 《Journal of Magnesium and Alloys》 SCIE EI CAS 2015年第2期134-141,共8页
For the purpose of investigating the dynamic deformational behavior and failure mechanisms of magnesium under high strain rates,the Split Hopkinson Pressure Bar(SHPB)was used for investigating dynamic mechanical prope... For the purpose of investigating the dynamic deformational behavior and failure mechanisms of magnesium under high strain rates,the Split Hopkinson Pressure Bar(SHPB)was used for investigating dynamic mechanical properties of extruded Mg-Gd-Y Magnesium alloy at ambient temperature(300 K),200℃(473 K)and 300℃(573 K)temperature.The samples after compression were analyzed by scanning electron microscope(SEM)and metallographic microscope.Dynamic mechanical properties,crack performance and plastic deformation mechanism of extruded Mg-Gd-Y Magnesium alloy along the extrusion direction(ED)were discussed.The results show that,extruded Mg-Gd-Y Magnesium alloy has the largest dynamic compressive strength which is 535 MPa at ambient temperature(300 K)and strain rate of 2826 s^(−1).When temperature increases,dynamic compressive strength decreases,while ductility increases.The dynamic compression fracture mechanism of extruded Mg-Gd-Y Magnesium alloy is multi-crack propagation and intergranular quasi-cleavage fracture at both ambient temperature and high temperature.The dynamic compressive deformation mechanism of extruded Mg-Gd-Y Magnesium alloy is a combination of twinning,slipping and dynamic recrystallization at both ambient temperature and high temperature. 展开更多
关键词 Extruded Mg-Gd-Y magnesium alloy Split Hopkinson Pressure Bar Dynamic compressive property failure behavior High strain rates High temperature
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Numerical simulations of failure behavior around a circular opening in a non-persistently jointed rock mass under biaxial compression 被引量:7
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作者 Yang Xuxu Jing Hongwen Chen Kunfu 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2016年第4期729-738,共10页
Pre-existing discontinuities change the mechanical properties of rock masses,and further influence failure behavior around an underground opening.In present study,the failure behavior in both Inner and Outer zones aro... Pre-existing discontinuities change the mechanical properties of rock masses,and further influence failure behavior around an underground opening.In present study,the failure behavior in both Inner and Outer zones around a circular opening in a non-persistently jointed rock mass under biaxial compression was investigated through numerical simulations.First,the micro parameters of the PFC^(3D) model were carefully calibrated using the macro mechanical properties determined in physical experiments implemented on jointed rock models.Then,a parametrical study was undertaken of the effect of stress condition,joint dip angle and joint persistency.Under low initial stress,the confining stress improves the mechanical behavior of the surrounding rock masses;while under high initial stress,the surrounding rock mass failed immediately following excavation.At small dip angles the cracks around the circular opening developed generally outwards in a step-path failure pattern;whereas,at high dip angles the surrounding rock mass failed in an instantaneous intact rock failure pattern.Moreover,the stability of the rock mass around the circular opening deteriorated significantly with increasing joint persistency. 展开更多
关键词 Underground opening failure behavior Non-persistent joints Rock mass PFC^3D
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Failure behavior and mechanical properties of novel dieless clinched joints with different sheet thickness ratios 被引量:1
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作者 QIN Deng-lin CHEN Chao 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第9期3077-3087,共11页
As one of the advanced and efficient means of joining,the clinching process is capable of joining sheets with different materials or different sheet thicknesses.In this article,a novel modified clinching process,i.e.,... As one of the advanced and efficient means of joining,the clinching process is capable of joining sheets with different materials or different sheet thicknesses.In this article,a novel modified clinching process,i.e.,the dieless clinching process,was executed to join AA6061 aluminum alloy with sheet thicknesses of 1.5,2.0,2.5 and 3.0 mm according to different sheet stack-ups.The geometrical characteristics,microhardness distribution,failure behavior,static strength,absorbed energy and instantaneous stiffness of the novel dieless joint were gotten and investigated.The results indicated that the sheet thickness ratio has a notable effect on the failure behavior and mechanical properties of the novel dieless clinched joint,and a relatively large sheet thickness ratio can improve the joint performance when joining sheets with different sheet thicknesses. 展开更多
关键词 joining clinching process sheet thickness ratio failure behavior mechanical properties
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Failure behavior of highly stressed rocks under quasi-static and intensive unloading conditions 被引量:3
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作者 Jie Li Pengxian Fan Mingyang Wang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2013年第4期287-293,共7页
Unloading failure of rocks,especially highly stressed rocks,is one of the key issues in construction of underground structures.Based on this,analytical models for rocks under quasi-static and intensive unloading condi... Unloading failure of rocks,especially highly stressed rocks,is one of the key issues in construction of underground structures.Based on this,analytical models for rocks under quasi-static and intensive unloading conditions are established to study the failure behavior of highly stressed rocks.In case of rock failure under quasi-static unloading,the rock mass ahead of working face is regarded as an elasto-brittle material,and the stress-displacement curves are used to characterize the tensile fracture of peak-stress area.It is observed that,when intensive unloading happens,there is an elastic unloading wave(perturbation wave) propagating in the rock mass.If the initial stress exceeds the critical stress,there will be a fracture wave,following the elastic unloading wave.To study the propagation feature of fracture wave,the conservation laws of mass,momentum and energy are employed.Results show that the post-peak deformation,strength and energy dissipation are essential to the failure process of highly stressed rocks. 展开更多
关键词 Deep rock mass Unloading failure behavior Quasi-static unloading Intensive unloading
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Failure behavior of interfacial domain in SiC-matrix based composites 被引量:5
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作者 Jinxue Ding Xiaokang Ma +3 位作者 Xiaomeng Fan Jimei Xue Fang Ye Laifei Cheng 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2021年第29期1-10,共10页
In this work,the microstructure,failure behavior and interfacial properties with respective to the interfacial domain in SiCf/BN/SiC and C_(f)/PyC/SiC composites were studied via the fiber push-in test.The differences... In this work,the microstructure,failure behavior and interfacial properties with respective to the interfacial domain in SiCf/BN/SiC and C_(f)/PyC/SiC composites were studied via the fiber push-in test.The differences in the mechanical response of the interfacial domain were observed.During the fiber push-in test for SiCf/BN/SiC,the interface debonding accompanied with interphase fracture occurred,resulting in an obvious sign of the onset of debonding on loading-displacement(P-u)curves.While the good continuity of P-u curves can be observed for Cf/PyC/SiC,which is due to that the failure is in the form of interface debonding along with interphase lateral slipping caused by the extension of buckled carbon fiber,without any interphase fracture.The interfacial properties calculated from the fiber push-in test show that Cf/PyC/SiC possesses a weaker interfacial domain compared with SiC_(f)/BN/SiC.The interfacial shear stress of SiCf/BN/SiC and C_(f)/PyC/SiC composites amounts 94.2 and 48.1 MPa,respectively. 展开更多
关键词 SiC-matrix based composites Interfacial domain Fiber push-in test failure behavior Interfacial mechanical properties
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Experimental and theoretical investigation of the failure behavior of a reinforced concrete target under high-energy penetration 被引量:2
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作者 Fanlin Meng Tianbao Ma Xiangzhao Xu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2020年第1期116-129,共14页
The dynamic mechanical properties of concrete and reinforced concrete targets subjected to high-speed projectile impact loading have a significant influence on the impact resistance of protective structures.In this st... The dynamic mechanical properties of concrete and reinforced concrete targets subjected to high-speed projectile impact loading have a significant influence on the impact resistance of protective structures.In this study,high-speed projectile penetration and perforation of concrete and reinforced concrete structures was carried out to determine the high-energy impact loading.The failure behaviors of projectile penetration and perforation of the concrete and reinforced concrete targets were investigated,and the destruction characteristics of the targets were measured.An analytical model was established using the principle of minimum potential energy.The results show that the theoretical predictions are consistent with the experimental data,indicating that the energy method is effective for predicting the dynamic mechanical properties of concrete and reinforced concrete targets under high-speed projectile penetration. 展开更多
关键词 Reinforced concrete PENETRATION Analytical model failure behavior
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Numerical investigation on failure behavior of steel plate under explosive loading 被引量:1
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作者 ZHENG Kai WANG ZhiHua 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2021年第6期1311-1324,共14页
The failure behavior of metal materials under strong dynamic loading such as explosive and impact loading has important applications in the fields of defense industry and civil security. In this study, a novel coupled... The failure behavior of metal materials under strong dynamic loading such as explosive and impact loading has important applications in the fields of defense industry and civil security. In this study, a novel coupled bidirectional weighted mapping method between Lagrange particles and Euler meshes is proposed to numerically simulate the dynamic response and failure process of steel structure under explosive loading. In this method, the Lagrange particles and Euler meshes are used to describe the materials that need to be accurately tracked and can more accurately characterize the deformation history and failure process of the material. A comparison between the numerical results and experimental data shows that this method can be used to solve large deformation problem of multi-medium materials and the failure problems of complex structures under strong impact loading. 展开更多
关键词 steel plate explosive loading coupled bidirectional mapping method failure behavior
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Failure behavior and criteria of metallic glasses
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作者 Yan Chen Lanhong Dai 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2022年第2期1-23,I0001,共24页
Metallic glasses(MGs)constitute an emerging class of advanced structural materials due to their excellent mechanical properties.However,brittle failure at room temperature and the resultant complicated fracture behavi... Metallic glasses(MGs)constitute an emerging class of advanced structural materials due to their excellent mechanical properties.However,brittle failure at room temperature and the resultant complicated fracture behavior greatly limit their wide engineering applications.Over the past decades,the deformation and fracture in ductile or brittle mode referring to material compositions,load conditions,sample size,etc.,have been widely studied,and significant progress has been made in understanding the failure behavior of MGs.Micromechanisms of fracture have been revealed involving shear banding,cavitation and the nature of the crack tip field.The ductile-to-brittle transition and inherent governing parameters have been found.To well describe and predict the failure behavior of MGs,failure criteria for ductile and brittle MGs have been established empirically or based on atomic interactions.In this paper,we provide a detailed review of the above advances and identify outstanding issues in the failure of MGs that need to be further clarified. 展开更多
关键词 Metallic glasses failure behavior Shear band CAVITATION failure criteria
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Restraint effect of partition wall on the tunnel floor heave in layered rock mass
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作者 YANG Yunyun HUANG Da +2 位作者 ZHONG Zhu LIU Yang PENG Jianbing 《Journal of Mountain Science》 SCIE CSCD 2024年第7期2462-2479,共18页
The presence of horizontal layered rocks in tunnel engineering significantly impacts the stability and strength of the surrounding rock mass,leading to floor heave in the tunnel.This study focused on preparing layered... The presence of horizontal layered rocks in tunnel engineering significantly impacts the stability and strength of the surrounding rock mass,leading to floor heave in the tunnel.This study focused on preparing layered specimens of rock-like material with varying thickness to investigate the failure behaviors of tunnel floors.The results indicate that thin-layered rock mass exhibits weak interlayer bonding,causing rock layers near the surface to buckle and break upwards when subjected to horizontal squeezing.With an increase in the layer thickness,a transition in failure mode occurs from upward buckling to shear failure along the plane,leading to a noticeable reduction in floor heave deformation.The primary cause of significant deformation in floor heave is upward buckling failure.To address this issue,the study proposes the installation of a partition wall in the middle of the floor to mitigate heave deformation of the rock layers.The results demonstrate that the partition wall has a considerable stabilizing effect on the floor,reducing the zone of buckling failure and minimizing floor heave deformation.It is crucial for the partition wall to be sufficiently high to prevent buckling failure and ensure stability.Through simulation calculations on an engineering example,it is confirmed that implementing a partition wall can effectively reduce floor heave and enhance the stability of tunnel floor. 展开更多
关键词 Layered rock Floor heave Horizontal compression test failure behavior Partition wall
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A multifunctional rock testing system for rock failure analysis under different stress states: Development and application 被引量:3
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作者 Shucai Li Jie Hu +4 位作者 Florian Amann Liping Li Hongliang Liu Shaoshuai Shi Pooya Hamdi 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2022年第5期1531-1544,共14页
The stress state in a rock mass is complex. Stress redistribution around underground excavation may lead to various failure modes, including compressive-shear, tensile-shear, and tensile failures. The ability to perfo... The stress state in a rock mass is complex. Stress redistribution around underground excavation may lead to various failure modes, including compressive-shear, tensile-shear, and tensile failures. The ability to perform laboratory tests with these complex stress states is significant for establishing new strength criteria. The present paper introduces a new rock testing system with “tensile-compressive-shear”loading functions. The device includes bi-directional and double-range hydraulic cylinders, auxiliary loading equipment, and roller rows that can perform direct compressive-shear tests, direct tensile tests,and direct tensile-shear tests. The testing system provides maximum vertical and lateral loading forces of2000 k N and allows testing cubical rock specimens with dimensions of 0.5 m × 0.5 m × 0.5 m. The performance of the testing machine was evaluated by testing a rock-like material based on cement mortar under compressive-shear, tensile, and tensile-shear stress states. The failure process and deformation characteristics were monitored during loading using acoustic emission(AE) transient recorder,piezoelectric AE sensors, a high-speed camera, and a thermal infrared camera. The failure mechanism was investigated by analyzing AE counts, AE amplitude, strain, and temperature changes on the rock specimen surface. The test results confirmed that the testing system could successfully simulate the abovementioned stress path. The AE counts and amplitude responses were influenced by different failure modes. The temperature response during the compressive-shear test indicated the development of a high-temperature band on the rock specimen surface. In contrast, a negligible temperature change was observed during the tensile and tensile-shear tests. The newly developed multifunctional rock testing system allows laboratory tests under various failure modes. The monitoring results of multiple variables during rock failure tests provide valuable information on failure characteristics. 展开更多
关键词 Rock testing system Compressive-shear test Tensile test Tensile-shear test failure behavior Multiple variable evolutions
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Microscale deformation behavior of sandstone mineral particles based on XCT scanning 被引量:1
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作者 Ya-guang QIN De-sheng GU +4 位作者 Jian-hua HU Dong-jie YANG Shao-wei MA Xin BAI Chun-di FENG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第4期1261-1276,共16页
This work aimed to quantify the physical and mechanical behavior of three-dimensional microstructures in rocks under uniaxial compression.A high-precision in situ XCT(X-ray transmission computed tomography)technology ... This work aimed to quantify the physical and mechanical behavior of three-dimensional microstructures in rocks under uniaxial compression.A high-precision in situ XCT(X-ray transmission computed tomography)technology was applied to investigating the behavior of mineral grains in sandstone:the movement,the rotation deformation,and the principal strains between fault zone and non-fault zone.The results indicate that after unloading,the shear strain of mineral grains is periodic in the radial direction,the strain of mineral grains in the fracture zone is about 30 times of the macro strain of the specimen,which is about 5 times in the non-fracture zone,and the shear strain near the fault zone is larger than the compressive strain,and there is the shear stress concentration feature. 展开更多
关键词 grain deformation in situ XCT failure behavior Stokes rotation material line
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Analysis of Failure of Unsaturated Soils
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作者 Ricardo Schiava Guillermo Etse 《Journal of Geological Resource and Engineering》 2014年第2期99-106,共8页
In this work, an analysis of failure condition in partially saturated soils using the extended Macari Runesson Sture Lade model is presented. The elastoplastic constitutive model is based on an extension of the well-k... In this work, an analysis of failure condition in partially saturated soils using the extended Macari Runesson Sture Lade model is presented. The elastoplastic constitutive model is based on an extension of the well-know MRS Lade model by Sture et al., whereby the suction and effective stress tensor are introduced as an additional independent and dependent stress components, respectively. The condition for discontinuous bifurcation in partially saturated porous media and the localized failure predictions of the proposed material formulation for different suctions are also analyzed and discussed. The localization analysis with this model demonstrates that an increment of the suction is related to a destabilizing effect of the discontinuous bifurcation so the localized failure can be diffuse or continuous. 展开更多
关键词 Unsaturated soil ELASTO-PLASTICITY failure behavior.
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Method for Evaluating the Reliability of Compressor Impeller of Turbocharger for Vehicle Application in Plateau Area 被引量:2
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作者 WANG Zheng WANG Zengquan +2 位作者 WANG A-na ZHUANG Li WANG Jinwei 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第6期1218-1225,共8页
As turbocharging diesel engines for vehicle application are applied in plateau area, the environmental adaptability of engines has drawn more attention. For the environmental adaptability problem of turbocharging dies... As turbocharging diesel engines for vehicle application are applied in plateau area, the environmental adaptability of engines has drawn more attention. For the environmental adaptability problem of turbocharging diesel engines for vehicle application, the present studies almost focus on the optimization of performance match between turbocharger and engine, and the reliability problem of turbocharger is almost ignored. The reliability problem of compressor impeller of turhocharger for vehicle application when diesel engines operate in plateau area is studied. Firstly, the rule that the rotational speed of turbocharger changes with the altitude height is presented, and the potential failure modes of compressor impeller are analyzed. Then, the failure behavior models of compressor impeller are built, and the reliability models of compressor impeller operating in plateau area are developed. Finally, the rule that the reliability of compressor impeller changes with the altitude height is studied, the measurements for improving the reliability of the compressor impellers of turbocharger operating in plateau area are given. The results indicate that when the operating speed of diesel engine is certain, the rotational speed of turbocharger increases with the increase of altitude height, and the failure risk of compressor impeller with the failure modes of hub fatigue and blade resonance increases. The reliability of compressor impeller decreases with the increase of altitude height, and it also decreases as the increase of number of the mission profile cycle of engine. The method proposed can not only be used to evaluating the reliability of compressor impeller when diesel engines operate in plateau area but also be applied to direct the structural optimization of compressor impeller. 展开更多
关键词 TURBOCHARGER plateau area compressor impeller failure behavior RELIABILITY
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Numerical investigation on interface enhancement mechanism of Ag-SnO_(2) contact materials with Cu additive 被引量:1
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作者 MAYuan-yuan LI Gui-jing FENGWen-jie 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第4期1085-1097,共13页
The electrical contact and mechanical performances of Ag-SnO_(2) contact materials are often improved by additives,especially Cu and its oxides.To reveal the improvement mechanism of metal additive,the effects of Cu n... The electrical contact and mechanical performances of Ag-SnO_(2) contact materials are often improved by additives,especially Cu and its oxides.To reveal the improvement mechanism of metal additive,the effects of Cu nanoparticles on the interface strength and failure behavior of the Ag-SnO_(2) contact materials are investigated by numerical simulations and experiments.Three-dimensional representative volume element(RVE)models for the Ag-SnO_(2) materials without and with Cu nanoparticles are established,and the cohesive zone model is used to simulate the interface debonding process.The results show that the stress−strain relationships and failure modes predicted by the simulation agree well with the experimental ones.The adhesion strengths of the Ag/SnO_(2) and Ag/Cu interfaces are respectively predicted to be 100 and 450 MPa through the inverse method.It is found that the stress concentration around the SnO_(2) phase is the primary reason for the interface debonding,which leads to the failure of Ag-SnO_(2) contact material.The addition of Cu particles not only improves the interface strength,but also effectively suppresses the initiation and propagation of cracks.The results have an reference value for improving the processability of Ag based contact materials. 展开更多
关键词 Ag-SnO_(2)contact material numerical simulation interface damage failure behavior
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Carbon nanotube films with ultrahigh thermal-shock and thermalshock-fatigue resistance characterized by ultra-fast ascending shock testing
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作者 Mingquan Zhu Shijun Wang +11 位作者 Yunxiang Bai Feng Gao Zhenxing Zhu Congying Wang Peng Zhang Hao Jin Hui Zhang Luqi Liu Zhiping Xu Xinghong Zhang Fei Wei Zhong Zhang 《Nano Research》 SCIE EI CSCD 2024年第8期6777-6784,共8页
The exploration of material failure behavior not only involves defining its limits and underlying mechanisms but also entails devising strategies for improvement and protection in extreme conditions.We've pioneere... The exploration of material failure behavior not only involves defining its limits and underlying mechanisms but also entails devising strategies for improvement and protection in extreme conditions.We've pioneered an advanced multi-scale,high-speed ascending thermal shock testing platform capable of inducing unprecedented heat shocks at rates surpassing 105℃/s.Through meticulous examination of the thermal shock responses of carbon nanotube(CNT)films,we've achieved remarkable breakthroughs.By employing an innovative macro-scale synchronous tightening and relaxing approach,we've attained a critical temperature differential in CNT films that exceeds an exceptional 2500℃—surpassing any previously reported metric for highperformance,thermal-shock-resistant materials.Notably,these samples have demonstrated exceptional resilience,retaining virtually unchanged strength even after enduring 10,000 thermal shock cycles at temperatures exceeding 1000℃.Furthermore,our research has revealed a novel thermal shock/fatigue failure mechanism that fundamentally diverges from conventional theories centered on thermal stress. 展开更多
关键词 carbon nanotubes failure behavior thermal shock CHARACTERIZATION
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Fatigue behavior of direct laser deposited Ti-6.5Al-2Zr-1Mo-1V titanium alloy and its life distribution model 被引量:7
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作者 Xiaofan HE Tianshuai WANG +2 位作者 Xiaobo WANG Weigang ZHAN Yuhai LI 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2018年第11期2124-2135,共12页
The present work aims to investigate the fatigue behavior of Direct Laser Deposition(DLD) Ti-6.5 Al-2 Zr-1 Mo-1 V titanium alloy under constant amplitude stress. 22 pieces of DLD Ti-6.5 Al-2 Zr-1 Mo-1 V titanium alloy... The present work aims to investigate the fatigue behavior of Direct Laser Deposition(DLD) Ti-6.5 Al-2 Zr-1 Mo-1 V titanium alloy under constant amplitude stress. 22 pieces of DLD Ti-6.5 Al-2 Zr-1 Mo-1 V titanium alloy standard cylinder specimens were tested under a stress level of 800 MPa with a stress ratio of 0.06. Fatigue fractography and fatigue life data were obtained.Through the fracture surface analysis, the specimens were divided into two categories in accordance with the location of crack initiation and defect types. Comparison of fatigue life and behavior between two specimen types was given, which was followed by a discussion about the impact of defect type, size and position on the fatigue life of the specimen. The fatigue test results also show a large variation of fatigue life. To illustrate the statistical characteristics of the fatigue life, probabilistic analysis was performed, and a novel bimodal lognormal model was established. The model has a good fit with the experimental data and can reduce the scatter of the fatigue life significantly. 展开更多
关键词 Additive Manufacturing Bimodal Lognormal distribution Direct Laser Deposition Fatigue life Mixed failure behavior
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Composite structural modeling and tensile mechanical behavior of graphene reinforced metal matrix composites 被引量:9
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作者 苏益士 李赞 +5 位作者 俞洋 赵蕾 李志强 郭强 熊定邦 张荻 《Science China Materials》 SCIE EI CSCD 2018年第1期112-124,共13页
Owing to its distinguished mechanical stiffness and strength, graphene has become an ideal reinforcing material in kinds of composite materials. In this work, the graphene(reduced graphene oxide) reinforced aluminum... Owing to its distinguished mechanical stiffness and strength, graphene has become an ideal reinforcing material in kinds of composite materials. In this work, the graphene(reduced graphene oxide) reinforced aluminum(Al)matrix composites were fabricated by flaky powder metallurgy. Tensile tests of pure Al matrix and graphene/Al composites with bioinspired layered structures are conducted.By means of an independently developed Python-based structural modeling program, three-dimensional microscopic structural models of graphene/Al composites can be established, in which the size, shape, orientation, location and content of graphene can be reconstructed in line with the actual graphene/Al composite structures. Elastoplastic mechanical properties, damaged materials behaviors, grapheneAl interfacial behaviors and reasonable boundary conditions are introduced and applied to perform the simulations. Based on the experimental and numerical tensile behaviors of graphene/Al composites, the effects of graphene morphology,graphene-Al interface, composite configuration and failure behavior within the tensile mechanical deformations of graphene/Al composites can be revealed and indicated, respectively.From the analysis above, a good understanding can be brought to light for the deformation mechanism of graphene/Al composites. 展开更多
关键词 graphene/Al composites structural modeling mechanical properties composite configuration failure behavior
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Application of the expanded distinct element method for the study of crack growth in rock-like materials under uniaxial compression 被引量:5
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作者 Lei YANG Yujing JIANG +2 位作者 Bo LI Shucai LI Yang GAO 《Frontiers of Structural and Civil Engineering》 SCIE EI 2012年第2期121-131,共11页
The expanded distinct element method(EDEM)was used to investigate the crack growth in rock-like materials under uniaxial compression.The tensile-shear failure criterion and the Griffith failure criterion were implante... The expanded distinct element method(EDEM)was used to investigate the crack growth in rock-like materials under uniaxial compression.The tensile-shear failure criterion and the Griffith failure criterion were implanted into the EDEM to determine the initiation and propagation of pre-existing cracks,respectively.Uniaxial compression experiments were also performed with the artificial rock-like samples to verify the validity of the EDEM.Simulation results indicated that the EDEM model with the tensile-shear failure criterion has strong capabilities for modeling the growth of pre-existing cracks,and model results have strong agreement with the failure and mechanical properties of experimental samples.The EDEM model with the Griffith failure criterion can only simulate the splitting failure of samples due to tensile stresses and is incapable of providing a comprehensive interpretation for the overall failure of rock masses.Research results demonstrated that sample failure primarily resulted from the growth of single cracks(in the form of tensile wing cracks and shear secondary cracks)and the coalescence of two cracks due to the growth of wing cracks in the rock bridge zone.Additionally,the inclination angle of the pre-existing crack clearly influences the final failure pattern of the samples. 展开更多
关键词 expanded distinct element method(EDEM) crack growth rock-like material tensile-shear failure criterion Griffith failure criterion mechanical and failure behavior
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