The insertion and extraction of lithium ions in active materials lead to significant volumetric deformation,resulting in stresses that drive the mechanical degradation of these materials.This accumulation of mechanica...The insertion and extraction of lithium ions in active materials lead to significant volumetric deformation,resulting in stresses that drive the mechanical degradation of these materials.This accumulation of mechanical degradation ultimately leads to mechanical failure in lithium-ion batteries(LIB).This paper summarizes the experimental characterization techniques used to observe the mechanical degradation of lithium battery cells,electrodes,and particles across macro,micro,and nano scales.Additionally,the mechanical failure model for LIB that spans from the microscopic to the macroscopic scale has been outlined.Finally,we analyze the current challenges and opportunities,including the standardization of battery measurements,the quantification of mechanical failures,and the correlation between mechanical failures and electrochemical performance.展开更多
Negative Poisson’s ratio materials and structures exhibit lateral expansion under tensile loading,demonstrating significant mechanical advantages over conventional materials.This study systematically investigated thr...Negative Poisson’s ratio materials and structures exhibit lateral expansion under tensile loading,demonstrating significant mechanical advantages over conventional materials.This study systematically investigated three typical two-dimensional negative Poisson’s ratio metamaterial structures(Concave honeycomb,Anti-chiral,and Anti-chiral concave honeycomb hybrid structures)through both experimental tests and numerical analysis.The test specimens were fabricated using selective laser melting(SLM)additive manufacturing technology,and the experimental test was conducted with the use of a DIC strain measurement system.The numerical studies were performed considering both static tensile loading and dynamic impact loading with different strain rates.The deformation behaviors,failure process,negative Poisson’s ratio effects,and energy absorption capacity of the three different metamaterial structures are systematically investigated,and the associated mechanical mechanisms are thoroughly revealed.Results and findings of this work could provide valuable guidance for the engineering design and application of negative Poisson’s ratio metamaterials and structures.展开更多
Lithium-ion batteries(LIBs)are susceptible to mechanical failures that can occur at various scales,including particle,electrode and overall cell levels.These failures are influenced by a combination of multi-physical ...Lithium-ion batteries(LIBs)are susceptible to mechanical failures that can occur at various scales,including particle,electrode and overall cell levels.These failures are influenced by a combination of multi-physical fields of electrochemical,mechanical and thermal factors,making them complex and multi-physical in nature.The consequences of these mechanical failures on battery performance,lifetime and safety vary depending on the specific type of failure.However,the complex nature of mechanical degradation in batteries often involves interrelated processes,in which different failure mechanisms interact and evolve.Despite extensive research efforts,the detailed mechanisms behind these failures still require further clarification.To bridge this knowledge gap,this review systematically investigates three key aspects:multiscale mechanical failures;their implications for performance,lifetime and safety;and the interconnections between the different types and scales of the mechanical failures.By adopting a multiscale and multidisciplinary perspective,fragmented ideas from current research are integrated into a comprehensive framework,providing a deeper understanding of the mechanical behaviors and interactions within LIBs.We highlight the main characteristics of mechanical failures in LIBs and present valuable insights and prospects in four key areas of theories,materials,designs and applications,for improving the performance,lifetime and safety of LIBs by addressing current challenges in the field.As a valuable resource,this review may serve as a bridge for researchers from diverse disciplines,facilitating their understanding of mechanical failures in LIBs and encouraging further advancements in the field.展开更多
Sodium-ion batteries(SIBs)have attracted significant attention in large-scale energy storage system because of their abundant sodium resource and cost-effectiveness.Layered oxide materials are particularly promising a...Sodium-ion batteries(SIBs)have attracted significant attention in large-scale energy storage system because of their abundant sodium resource and cost-effectiveness.Layered oxide materials are particularly promising as SIBs cathodes due to their high theoretical capacities and facile synthesis.However,their practical applications are hindered by the limitations in energy density and cycling stability.The comprehensive understanding of failure mechanisms within bulk structure and at the cathode/electrolyte interface of cathodes is still lacking.In this review,the issues related to bulk phase degradation and surface degradation,such as irreversible phase transitions,cation migration,transition metal dissolution,air/moisture instability,intergranular cracking,interfacial reactions,and reactive oxygen loss,are discussed.The latest advances and strategies to improve the stability of layered oxide cathodes and full cells are provided,as well as our perspectives on the future development of SIBs.展开更多
Calcareous sands are widely distributed on the coral reefs,continental shelf,and seashores between 30north and south latitude and are commonly utilized as filling materials for the construction of artificial islands a...Calcareous sands are widely distributed on the coral reefs,continental shelf,and seashores between 30north and south latitude and are commonly utilized as filling materials for the construction of artificial islands and infrastructure foundations.In this study,calcareous sands were cemented by enzymatically induced carbonate precipitation(EICP)technique.Drained triaxial tests were conducted on the EICPtreated calcareous sands.Results showed that the specimens with different cementation levels exhibited different responses in mechanical behavior.The differences in the sand fabric after consolidation under a relatively high confining pressure resulted in the untreated specimen exhibiting a higher peak strength compared to the lightly cemented specimen.High confining pressures exhibited a strongly inhibiting effect on dilatancy,which could be counteracted by increasing the cementation level.The EICP-treated specimen could have one or two yield points(smaller-strain and larger-strain yields).For lightly cemented specimens,the smaller-strain yield stress decreased under high confining pressures due to the partial carbonate bonding degradation during consolidation.The stress line of untreated particle breakage(UPB)was a critical boundary to distinguish failure mode in the p′-q space.For the EICP-treated specimens,the yield stress located above or below the UPB stress line indicates the simultaneous or sequential breakage of the carbonate bonds and sand particles,respectively.Accordingly,the EICPtreated specimen exhibited brittle or ductile properties.Failure mode transformation could be triggered by increasing cementation level or confining pressure.展开更多
Composite rock layers are widely present in mining and tunnel construction projects,and are prone to dynamic tensile failure along bedding planes under dynamic disturbances.To ensure engineering safety,it is necessary...Composite rock layers are widely present in mining and tunnel construction projects,and are prone to dynamic tensile failure along bedding planes under dynamic disturbances.To ensure engineering safety,it is necessary to conduct research on the dynamic tensile characteristics under different working conditions.Considering the difficulty of on-site sampling,composite rock samples were prepared with cement mortar,and dynamic Brazilian splitting tests were carried out using split Hopkinson pressure bar(SHPB)equipment,a high-speed camera,and PFC^(2D)numerical software to explore their dynamic tensile properties under dynamic disturbance under different strength ratios and other factors.The results show that the dynamic tensile strength of samples exhibits a rising trend with the strength ratio and strain rate growth.As the incident angle increases from 0°to 90°,the stress contour deflects transform from center-splitting failure to tension-shear combined failure and back again.The influence of the incident order in different lithology rocks on the dynamic tensile strength of composite samples is controlled by strain rate,and when the strain rate increases to 400 s^(-1),the difference in strength due to the sequence of incident stress waves is within 5%.Based on PFC^(2D),the strength ratio of composite samples has a certain influence on the distribution of microfractures.With strength ratios equaling 1.5 or 2.0,the cracks are mainly concentrated on the softer material side,while a large number of cracks are distributed on both sides of the bedding plane with a strength ratio equal to 1.2.展开更多
Mechanical stability is critically essential in the design of thermoelectric devices.In this study,we employed first-principles calculations based on density functional theory to investigate the failure mechanisms at ...Mechanical stability is critically essential in the design of thermoelectric devices.In this study,we employed first-principles calculations based on density functional theory to investigate the failure mechanisms at the CoSb_(3)/Ni interface.Our findings reveal that the CoSb_(3)(100)/Ni(100)and CoSb_(3)(100)/Ni(111)_1 configurations are favorable interface structures.The ideal tensile strength of the CoSb_(3)/Ni interface is markedly lower than that of bulk CoSb_(3),which can be attributed to structural rearrangements near the interface that weaken the strength of the Co–Sb bonds.Interface failure occurs in CoSb_(3),where covalent Sb–Sb bonds exhibit a tendency to soften prior to the ionic Co–Sb bonds due to their comparatively lower rigidity.Consequently,the breakage of the Co–Sb bonds leads to interface failure.Structural failure at both single-layer Sb_CoSb_(3)(100)/Ni(100)and single-layer Sb_CoSb_(3)(100)/Ni(111)_1 interfaces results from ruptures in intermediate Co–Sb bonds in CoSb_(3),whereas failures at double-layer Sb_CoSb_(3)(100)/Ni(100)and double-layer Sb_CoSb_(3)(100)/Ni(111)_1 interfaces stem from fractures in the uppermost Co–Sb bonds.This behavior is primarily driven by atomic rearrangements near the single-layer Sb_CoSb_(3)interface,which promote bond formation between Sb–Ni and Co–Ni,thereby enhancing stability within the superstructure of CoSb_(3).This study will provide a theoretical basis for the interface design of thermoelectric devices.展开更多
Utilizing coarse aggregates containing mining waste rock for backfilling addresses the strength requirements and reduces the expenses associated with binder and solid waste treatment.However,this type of material is p...Utilizing coarse aggregates containing mining waste rock for backfilling addresses the strength requirements and reduces the expenses associated with binder and solid waste treatment.However,this type of material is prone to aggregate segregation,which can lead to uneven deformation and damage to the backfill.We employed an image-segmentation method that incorporated machine learning to analyze the distribution information of the aggregates on the splitting surface of the test blocks.The results revealed a nonlinear rela-tionship between aggregate segregation and variations in solid concentration(SC)and cement/aggregate ratio(C/A).The SC of 81wt%-82wt%and C/A of 10.00wt%-12.50wt%reflect surges in fluid dynamics,friction effects,and shifts in their dominance.A uniaxial compression experiment,supplemented with additional strain gauges and digital image correlation technology,enabled us to analyze the mechanical properties and failure mechanism under the influence of aggregate segregation.It was found that the uniaxial compressive strength,ranging from 1.75 MPa to 12.65 MPa,is linearly related to both the SC and C/A,and exhibits no significant relation-ship with the degree of segregation in numerical terms.However,the degree of segregation affects the development trend of the elastic modulus to a certain extent,and a standard deviation of the aggregate area ratio of less than 1.63 clearly indicates a higher elastic modu-lus.In the pouring direction,the top area of the test block tended to form a macroscopic fracture surface earlier.By contrast,the compressibility of the bottom area was greater than that of the top area.The intensification of aggregate segregation widened the differences in the deformation and failure characteristics between the different areas.For samples with different uniformities,significant differences in local deformation ranging from 515.00μεto 1693.70μεwere observed during the stable deformation stage.The extreme unevenness of the aggregate leads to rapid crack penetration in the sample,causing macroscopic tensile failure and resulting in premature structural failure.展开更多
Exploring dynamic mechanical responses and failure behaviors of hot dry rock(HDR)is significant for geothermal exploitation and stability assessment.In this study,via the split Hopkinson pressure bar(SHPB)system,a ser...Exploring dynamic mechanical responses and failure behaviors of hot dry rock(HDR)is significant for geothermal exploitation and stability assessment.In this study,via the split Hopkinson pressure bar(SHPB)system,a series of dynamic compression tests were conducted on granite treated by cyclic thermal shocks at different temperatures.We analyzed the effects of cyclic thermal shock on the thermal-related physical and dynamic mechanical behaviors of granite.Specifically,the P-wave velocity,dynamic strength,and elastic modulus of the tested granite decrease with increasing temperature and cycle number,while porosity and peak strain increase.The degradation law of dynamic mechanical properties could be described by a cubic polynomial.Cyclic thermal shock promotes shear cracks propagation,causing dynamic failure mode of granite to transition from splitting to tensile-shear composite failure,accompanied by surface spalling and debris splashing.Moreover,the thermal shock damage evolution and coupled failure mechanism of tested granite are discussed.The evolution of thermal shock damage with thermal shock cycle numbers shows an obvious S-shaped surface,featured by an exponential correlation with dynamic mechanical parameters.In addition,with increasing thermal shock temperature and cycles,granite mineral species barely change,but the length and width of thermal cracks increase significantly.The non-uniform expansion of minerals,thermal shock-induced cracking,and water-rock interaction are primary factors for deteriorating dynamic mechanical properties of granite under cyclic thermal shock.展开更多
Rock-like specimens containing a joint with different inclination angles and roughness were prepared using 3D printing technology.Then,true triaxial compression loading experiments were conducted on those jointed spec...Rock-like specimens containing a joint with different inclination angles and roughness were prepared using 3D printing technology.Then,true triaxial compression loading experiments were conducted on those jointed specimens.The increase in roughness leads to an increase in the axial strength and peak strain.With the increasing inclination angle,the axial strength initially decreases from 30°to 60°and then increases from 60°to 90°.While the peak strain first rises from 30°to 45°and then declines from 45°to 90°.The variation in failure mode results from differences in lateral stress on the joints under different strike directions.Specimens with joint strike parallel to the intermediate principal stress predominantly showed matrix or matrix-joint mixed shear failure,whereas those parallel to the minimum principal stress exhibited matrix shear failure.The analysis results of acoustic emission signals indicate the crack number and shear crack percentage increase with the increasing roughness and first decrease(30°to 60°),then increase(60°to 90°)with the increasing inclination angle.The research results can provide some guidance for the design and support of underground engineering with jointed surrounding rock.展开更多
After the excavation of deep mining tunnels and underground caverns,the stability of surrounding rock controlled by structural planes is prone to structural damage and even engineering disasters due to three-dimension...After the excavation of deep mining tunnels and underground caverns,the stability of surrounding rock controlled by structural planes is prone to structural damage and even engineering disasters due to three-dimensional stress redistribution and multi-directional dynamic construction interference.However,the shear mechanical behavior,fracture evolution mechanism and precursor characteristics of rockmass under true triaxial stress and multi-directional coupling disturbance are not unclear.Therefore,this study carried out true triaxial shear tests on limestone intermittent structural planes under uni-,bi-and tri-directional coupling disturbances to analyze its mechanical behavior,fracture evolution mechanism and precursor characteristics.The results show that as the disturbance direction increase,the shear strength of limestone generally decreases,while the roughness of structural planes and the degree of anisotropy generally exhibit an increasing trend.The proportion of shear cracks on the structural plane increases with the increase of shear stress.The disturbance strain rate before failure shows a U-shaped trend.Near to disturbance failure,there were more high-energy and high-amplitude acoustic emission events near the structural plane,and b-value drops rapidly below 1,while lgN/b ratio increased to above 3.These findings provide experimental recognition and theoretical support for assessing the stability of rockmass under blasting excavation.展开更多
Based on the high-purity single-crystal tungsten nanowire firstly prepared by the metal-catalyzed vapor-phase reaction method, molecular dynamics method was used to calculate tensile stress-strain curves and simulate ...Based on the high-purity single-crystal tungsten nanowire firstly prepared by the metal-catalyzed vapor-phase reaction method, molecular dynamics method was used to calculate tensile stress-strain curves and simulate microscopic deformation structures of the single-crystal tungsten nanowires with different crystal orientations of 〈100〉, 〈110〉and 〈111〉, in order to reveal the effect of crystal orientation on their tensile mechanical properties and failure mechanisms. Research results show that all of the stress-strain curves are classified into four stages： elastic stage, damage stage, yielding stage and failure stage, where 〈100〉orientation has a special hardening stage after yielding and two descending stages. The crystal orientation has little effect on elastic modulus but great effect on tensile strength, yielding strength and ductility, depending on different atomic surface energies and principal sliding planes. The calculated values of elastic modulus are in good agreement with the tested values of elastic modulus.展开更多
To investigate the long-term stability of soft-hard interbedded rock masses with initial damage induced by earthquakes and periodic drying and wetting,this study prepared samples with different initial damage through ...To investigate the long-term stability of soft-hard interbedded rock masses with initial damage induced by earthquakes and periodic drying and wetting,this study prepared samples with different initial damage through cyclic loading and unloading(CLU)experiments followed by cyclic drying and wetting(CDW)experiments,and finally conducted creep experiments.The study analyzed the effects of initial damage on creep mechanical behavior,crack evolution,and explored failure precursor information,revealing the damage failure mechanisms.The results show that the structural characteristics of the rock mass control its macroscopic failure mode.Initial damage promotes microcrack development,influences the fracture mode,and increases the proportion of high-frequency(200−280 kHz)acoustic emission events during creep.Meanwhile,initial damage exacerbates creep characteristics,increasing the creep rate,shortening total creep failure time,and reducing long-term strength.The damage failure is attributed to:the generation of internal cracks and pores in the rock caused by CLU;mineral hydrolysis and expansion-contraction due to CDW,resulting in weakened intergranular cementation;and full development of cracks and pores under creep stress.Additionally,the deformation difference coefficient and the coefficient of variation of RA/AF values can serve as precursor indicators for creep failure.展开更多
This study introduces electromagnetic dynamic self-piercing riveting(ED-SPR),an innovative technique that integrates electromagnetic riveting principles with static self-piercing riveting(S-SPR)for highperformance str...This study introduces electromagnetic dynamic self-piercing riveting(ED-SPR),an innovative technique that integrates electromagnetic riveting principles with static self-piercing riveting(S-SPR)for highperformance structural joints.A dedicated methodology and experimental apparatus for ED-SPR were systematically designed and validated.Quantitative comparative analyses between ED-SPR and S-SPR were conducted on three critical material combinations:CFRP/Al,low-strength steel HC340 LA/Al,and high-strength steel DP590/Al.Key findings demonstrate that the electromagnetic-driven process reduces installation resistance by 60%and achieves a 30%larger interlock distance at the joint base compared to S-SPR.These quantitative advantages directly contribute to an approximately 30%increase in load-bearing capacity and superior damage tolerance in ED-SPR joints,as evidenced by tensile-shear testing of single-lap joints.Furthermore,distinct failure modes were observed:ED-SPR joints exhibited top plate pull-out failure in CFRP/Al and DP590/Al configurations,contrasting with the predominant rivet pull-out failure in S-SPR counterparts.Surface morphology and damage evolution were characterized via scanning electron microscopy(SEM)on post-assembly and tensile-failed specimens.The study establishes a foundation for optimizing electromagnetic-driven riveting parameters to mitigate CFRP delamination and further enhance joint reliability in vehicle body and aircraft fuselage structures.展开更多
Shield tunneling in saturated ground poses challenges due to the potential risk of ground collapse resulting from seepage force and inadequate support pressure.This study employed a laboratory model test and a theoret...Shield tunneling in saturated ground poses challenges due to the potential risk of ground collapse resulting from seepage force and inadequate support pressure.This study employed a laboratory model test and a theoretical validation to elucidate the mechanisms of face failure and subsequent ground collapse in saturated ground during slurry pressure-balanced shield(SPBS)tunneling operations.A slurry circulation system was developed to ensure steady shield tunneling and to replicate the phenomena of ground collapse.Investigations into shield tunneling parameters and ground responses,including soil pressure,pore water pressure,and surface subsidence,were conducted to understand the mechanisms of face failure and subsequent ground collapse.The theoretical solution for the critical collapse pressure of the tunnel face,based on the rotational failure mechanism,was validated through the comparison with the experimentally determined critical collapse pressure.The results indicate that:(1)appropriate adjustments of tunneling parameters are crucial for promoting filtercake formation,maintaining chamber pressure,and minimizing ground subsidence;(2)chamber pressure,soil pressure,pore water pressure,and ground subsidence are closely correlated with shield tunneling parameters and the formation of filter cake;(3)ground collapse follows a continuous failure mode due to the destruction of filtercake and the decrease in chamber pressure;(4)the soil pressure at the cutterhead is more sensitive to disturbances from shield tunneling than chamber pressure;and(5)experimentally determined critical collapse pressures is consistent with the theoretical solution of limit analysis.展开更多
The failure mechanisms and structural damage of SiC MOSFETs induced by heavy ion irradiation were demonstrated.The findings reveal three degradation modes,depending on the drain voltage.At a relatively low voltage,the...The failure mechanisms and structural damage of SiC MOSFETs induced by heavy ion irradiation were demonstrated.The findings reveal three degradation modes,depending on the drain voltage.At a relatively low voltage,the damage is triggered by the formation and activation of gate latent damage(LDs),with damage concentrated in the gate oxide.The second degradation mode involves permanent leakage current degradation,with damage progressively transitioning from the oxide to the SiC material as the drain voltage escalates.Ultimately,the device undergoes catastrophic burnout above certain voltages,characterized by the lattice temperature reaching the sublimation point of SiC,resulting in surface cavity and complete structural destruction.This paper presents a comprehensive investigation of SiC MOSFETs under heavy ion exposure,providing radiation resistance methods of SiC-based devices for aerospace applications.展开更多
Self-piercing riveting(SPR)is a cold forming technique used to fasten together two or more sheets of materials with a rivet without the need to predrill a hole.The application of SPR in the automotive sector has becom...Self-piercing riveting(SPR)is a cold forming technique used to fasten together two or more sheets of materials with a rivet without the need to predrill a hole.The application of SPR in the automotive sector has become increasingly popular mainly due to the growing use of lightweight materials in transportation applications.However,SPR joining of these advanced light materials remains a challenge as these materials often lack a good combination of high strength and ductility to resist the large plastic deformation induced by the SPR process.In this paper,SPR joints of advanced materials and their corresponding failure mechanisms are discussed,aiming to provide the foundation for future improvement of SPR joint quality.This paper is divided into three major sections:1)joint failures focusing on joint defects originated from the SPR process and joint failure modes under different mechanical loading conditions,2)joint corrosion issues,and 3)joint optimisation via process parameters and advanced techniques.展开更多
Lots of field investigations have proven that layer-crack structure usually appears during the excavation process of deep rock or coal mass.To provide experimental data for studying the formation mechanism of layer-cr...Lots of field investigations have proven that layer-crack structure usually appears during the excavation process of deep rock or coal mass.To provide experimental data for studying the formation mechanism of layer-crack structure,this study researches the influence of lateral pressure on the mechanical behavior of different rock types.Four rock types have been tested and the formation mechanism of macro-fracture surface is analyzed.Results indicate that the brittleness and burst proneness of rock or coal material are stronger than that of gypsum material due to the different mineral compositions and structures.When the lateral pressure is less than 10%uniaxial strength,the peak stress and elastic modulus increase with the increase of lateral pressure;but when the lateral pressure is larger than 10%uniaxial strength,the two parameters decrease slightly or keep steady.This is because when the lateral pressure reaches a certain value,local failure will be formed during the process of applying lateral pressure.Under the condition of low lateral pressure,the failure of the specimen is dominated by the tensile mechanism;under the condition of relatively high lateral pressure,the area of the specimen close to the free surface is tensile splitting failure,and the area far from the free surface is shear failure.展开更多
A new unified macro- and micro-mechanics failure analysis method for composite structures was developed in order to take the effects of composite micro structure into consideration. In this method, the macro stress di...A new unified macro- and micro-mechanics failure analysis method for composite structures was developed in order to take the effects of composite micro structure into consideration. In this method, the macro stress distribution of composite structure was calculated by commercial finite element analysis software. According to the macro stress distribution, the damage point was searched and the micro-stress distribution was calculated by reformulated finite-volume direct averaging micromechanics （FVDAM）, which was a multi-scale finite element method for composite. The micro structure failure modes were estimated with the failure strength of constituents. A unidirectional composite plate with a circular hole in the center under two kinds of loads was analyzed with the traditional macro-mechanical failure analysis method and the unified macro- and micro-mechanics failure analysis method. The results obtained by the two methods are consistent, which show this new method＇s accuracy and efficiency.展开更多
The mechanical behavior and failure mechanism of recycled semi-flexible pavement material were investigated by different scales method. The macroscopic mechanical behavior of samples was studied by static and dynamic ...The mechanical behavior and failure mechanism of recycled semi-flexible pavement material were investigated by different scales method. The macroscopic mechanical behavior of samples was studied by static and dynamic splitting tensile tests on mechanics testing system(MTS). The mechanical analysis in micro scale was carried out by material image analysis method and finite element analysis system. The strains of recycled semi-flexible pavement material on samples surface and in each phase materials were obtained. The test results reveal that the performance of recovered asphalt binder was the major determinant on the structural stability of recycled semi-flexible pavement material. The asphalt binder with high viscoelasticity could delay the initial cracking time and reduce the residual strain under cyclic loading conditions. The failure possibility order of each phase in recycled semi-flexible pavement material was asphalt binder, reclaimed aggregate, cement paste and virgin aggregate.展开更多
基金funded by the Key Research and Development Project of Guangdong Province(No.2023B0909050004)the National Natural Science Foundation of China(No.12402214).
文摘The insertion and extraction of lithium ions in active materials lead to significant volumetric deformation,resulting in stresses that drive the mechanical degradation of these materials.This accumulation of mechanical degradation ultimately leads to mechanical failure in lithium-ion batteries(LIB).This paper summarizes the experimental characterization techniques used to observe the mechanical degradation of lithium battery cells,electrodes,and particles across macro,micro,and nano scales.Additionally,the mechanical failure model for LIB that spans from the microscopic to the macroscopic scale has been outlined.Finally,we analyze the current challenges and opportunities,including the standardization of battery measurements,the quantification of mechanical failures,and the correlation between mechanical failures and electrochemical performance.
基金supported by the National Natural Science Foundation of China(No.12472136)Innovation Fund of Marine Defense Technology Innovation Center(No.25GFC-JJ16-3608).
文摘Negative Poisson’s ratio materials and structures exhibit lateral expansion under tensile loading,demonstrating significant mechanical advantages over conventional materials.This study systematically investigated three typical two-dimensional negative Poisson’s ratio metamaterial structures(Concave honeycomb,Anti-chiral,and Anti-chiral concave honeycomb hybrid structures)through both experimental tests and numerical analysis.The test specimens were fabricated using selective laser melting(SLM)additive manufacturing technology,and the experimental test was conducted with the use of a DIC strain measurement system.The numerical studies were performed considering both static tensile loading and dynamic impact loading with different strain rates.The deformation behaviors,failure process,negative Poisson’s ratio effects,and energy absorption capacity of the three different metamaterial structures are systematically investigated,and the associated mechanical mechanisms are thoroughly revealed.Results and findings of this work could provide valuable guidance for the engineering design and application of negative Poisson’s ratio metamaterials and structures.
基金support from the China Scholarship Council,the National Natural Science Foundation of China(52375144,52375145 and 52205153)the China Postdoctoral Science Foundation(2022M721138 and 2023T160216)+1 种基金Shanghai Pujiang Programme(23PJD019)the East China University of Science and Technology,and the University of Strathclyde during the course of this work.
文摘Lithium-ion batteries(LIBs)are susceptible to mechanical failures that can occur at various scales,including particle,electrode and overall cell levels.These failures are influenced by a combination of multi-physical fields of electrochemical,mechanical and thermal factors,making them complex and multi-physical in nature.The consequences of these mechanical failures on battery performance,lifetime and safety vary depending on the specific type of failure.However,the complex nature of mechanical degradation in batteries often involves interrelated processes,in which different failure mechanisms interact and evolve.Despite extensive research efforts,the detailed mechanisms behind these failures still require further clarification.To bridge this knowledge gap,this review systematically investigates three key aspects:multiscale mechanical failures;their implications for performance,lifetime and safety;and the interconnections between the different types and scales of the mechanical failures.By adopting a multiscale and multidisciplinary perspective,fragmented ideas from current research are integrated into a comprehensive framework,providing a deeper understanding of the mechanical behaviors and interactions within LIBs.We highlight the main characteristics of mechanical failures in LIBs and present valuable insights and prospects in four key areas of theories,materials,designs and applications,for improving the performance,lifetime and safety of LIBs by addressing current challenges in the field.As a valuable resource,this review may serve as a bridge for researchers from diverse disciplines,facilitating their understanding of mechanical failures in LIBs and encouraging further advancements in the field.
基金supported by the National Natural Science Foundation of China(Grant No.W2412060,22325902 and 52171215)the State Key Laboratory of Clean Energy Utilization(Open Fund Project No.ZJUCEU2023002)。
文摘Sodium-ion batteries(SIBs)have attracted significant attention in large-scale energy storage system because of their abundant sodium resource and cost-effectiveness.Layered oxide materials are particularly promising as SIBs cathodes due to their high theoretical capacities and facile synthesis.However,their practical applications are hindered by the limitations in energy density and cycling stability.The comprehensive understanding of failure mechanisms within bulk structure and at the cathode/electrolyte interface of cathodes is still lacking.In this review,the issues related to bulk phase degradation and surface degradation,such as irreversible phase transitions,cation migration,transition metal dissolution,air/moisture instability,intergranular cracking,interfacial reactions,and reactive oxygen loss,are discussed.The latest advances and strategies to improve the stability of layered oxide cathodes and full cells are provided,as well as our perspectives on the future development of SIBs.
基金funding support from the National Nature Science Foundation of China(Grant No.42030714).
文摘Calcareous sands are widely distributed on the coral reefs,continental shelf,and seashores between 30north and south latitude and are commonly utilized as filling materials for the construction of artificial islands and infrastructure foundations.In this study,calcareous sands were cemented by enzymatically induced carbonate precipitation(EICP)technique.Drained triaxial tests were conducted on the EICPtreated calcareous sands.Results showed that the specimens with different cementation levels exhibited different responses in mechanical behavior.The differences in the sand fabric after consolidation under a relatively high confining pressure resulted in the untreated specimen exhibiting a higher peak strength compared to the lightly cemented specimen.High confining pressures exhibited a strongly inhibiting effect on dilatancy,which could be counteracted by increasing the cementation level.The EICP-treated specimen could have one or two yield points(smaller-strain and larger-strain yields).For lightly cemented specimens,the smaller-strain yield stress decreased under high confining pressures due to the partial carbonate bonding degradation during consolidation.The stress line of untreated particle breakage(UPB)was a critical boundary to distinguish failure mode in the p′-q space.For the EICP-treated specimens,the yield stress located above or below the UPB stress line indicates the simultaneous or sequential breakage of the carbonate bonds and sand particles,respectively.Accordingly,the EICPtreated specimen exhibited brittle or ductile properties.Failure mode transformation could be triggered by increasing cementation level or confining pressure.
基金Project(242102320036)supported by the Science and the Technology Development Plant of Henan Province,ChinaProject(52278367)supported by the National Natural Science Foundation of China。
文摘Composite rock layers are widely present in mining and tunnel construction projects,and are prone to dynamic tensile failure along bedding planes under dynamic disturbances.To ensure engineering safety,it is necessary to conduct research on the dynamic tensile characteristics under different working conditions.Considering the difficulty of on-site sampling,composite rock samples were prepared with cement mortar,and dynamic Brazilian splitting tests were carried out using split Hopkinson pressure bar(SHPB)equipment,a high-speed camera,and PFC^(2D)numerical software to explore their dynamic tensile properties under dynamic disturbance under different strength ratios and other factors.The results show that the dynamic tensile strength of samples exhibits a rising trend with the strength ratio and strain rate growth.As the incident angle increases from 0°to 90°,the stress contour deflects transform from center-splitting failure to tension-shear combined failure and back again.The influence of the incident order in different lithology rocks on the dynamic tensile strength of composite samples is controlled by strain rate,and when the strain rate increases to 400 s^(-1),the difference in strength due to the sequence of incident stress waves is within 5%.Based on PFC^(2D),the strength ratio of composite samples has a certain influence on the distribution of microfractures.With strength ratios equaling 1.5 or 2.0,the cracks are mainly concentrated on the softer material side,while a large number of cracks are distributed on both sides of the bedding plane with a strength ratio equal to 1.2.
基金supported by the National Natural Science Foundation of China(Nos.92163212,92163215,and 92163119)support by Act 211 Government of the Russian Federation,under No.02.A03.21.0011by the Supercomputer Simulation Laboratory of South Ural State University.
文摘Mechanical stability is critically essential in the design of thermoelectric devices.In this study,we employed first-principles calculations based on density functional theory to investigate the failure mechanisms at the CoSb_(3)/Ni interface.Our findings reveal that the CoSb_(3)(100)/Ni(100)and CoSb_(3)(100)/Ni(111)_1 configurations are favorable interface structures.The ideal tensile strength of the CoSb_(3)/Ni interface is markedly lower than that of bulk CoSb_(3),which can be attributed to structural rearrangements near the interface that weaken the strength of the Co–Sb bonds.Interface failure occurs in CoSb_(3),where covalent Sb–Sb bonds exhibit a tendency to soften prior to the ionic Co–Sb bonds due to their comparatively lower rigidity.Consequently,the breakage of the Co–Sb bonds leads to interface failure.Structural failure at both single-layer Sb_CoSb_(3)(100)/Ni(100)and single-layer Sb_CoSb_(3)(100)/Ni(111)_1 interfaces results from ruptures in intermediate Co–Sb bonds in CoSb_(3),whereas failures at double-layer Sb_CoSb_(3)(100)/Ni(100)and double-layer Sb_CoSb_(3)(100)/Ni(111)_1 interfaces stem from fractures in the uppermost Co–Sb bonds.This behavior is primarily driven by atomic rearrangements near the single-layer Sb_CoSb_(3)interface,which promote bond formation between Sb–Ni and Co–Ni,thereby enhancing stability within the superstructure of CoSb_(3).This study will provide a theoretical basis for the interface design of thermoelectric devices.
基金funded by the National Natural Science Foundation of China(Nos.52130404 and 52304121)the Fundamental Research Funds for the Central Universities,China(No.FRF-TP-22-112A1).
文摘Utilizing coarse aggregates containing mining waste rock for backfilling addresses the strength requirements and reduces the expenses associated with binder and solid waste treatment.However,this type of material is prone to aggregate segregation,which can lead to uneven deformation and damage to the backfill.We employed an image-segmentation method that incorporated machine learning to analyze the distribution information of the aggregates on the splitting surface of the test blocks.The results revealed a nonlinear rela-tionship between aggregate segregation and variations in solid concentration(SC)and cement/aggregate ratio(C/A).The SC of 81wt%-82wt%and C/A of 10.00wt%-12.50wt%reflect surges in fluid dynamics,friction effects,and shifts in their dominance.A uniaxial compression experiment,supplemented with additional strain gauges and digital image correlation technology,enabled us to analyze the mechanical properties and failure mechanism under the influence of aggregate segregation.It was found that the uniaxial compressive strength,ranging from 1.75 MPa to 12.65 MPa,is linearly related to both the SC and C/A,and exhibits no significant relation-ship with the degree of segregation in numerical terms.However,the degree of segregation affects the development trend of the elastic modulus to a certain extent,and a standard deviation of the aggregate area ratio of less than 1.63 clearly indicates a higher elastic modu-lus.In the pouring direction,the top area of the test block tended to form a macroscopic fracture surface earlier.By contrast,the compressibility of the bottom area was greater than that of the top area.The intensification of aggregate segregation widened the differences in the deformation and failure characteristics between the different areas.For samples with different uniformities,significant differences in local deformation ranging from 515.00μεto 1693.70μεwere observed during the stable deformation stage.The extreme unevenness of the aggregate leads to rapid crack penetration in the sample,causing macroscopic tensile failure and resulting in premature structural failure.
基金The authors are grateful for the financial support from the National Natural Science Foundation of China(Grant Nos.52225904 and 52039007)the Natural Science Foundation of Sichuan Province(Grant No.2023NSFSC0377)supported by the New Cornerstone Science Foundation through the XPLORER PRIZE.
文摘Exploring dynamic mechanical responses and failure behaviors of hot dry rock(HDR)is significant for geothermal exploitation and stability assessment.In this study,via the split Hopkinson pressure bar(SHPB)system,a series of dynamic compression tests were conducted on granite treated by cyclic thermal shocks at different temperatures.We analyzed the effects of cyclic thermal shock on the thermal-related physical and dynamic mechanical behaviors of granite.Specifically,the P-wave velocity,dynamic strength,and elastic modulus of the tested granite decrease with increasing temperature and cycle number,while porosity and peak strain increase.The degradation law of dynamic mechanical properties could be described by a cubic polynomial.Cyclic thermal shock promotes shear cracks propagation,causing dynamic failure mode of granite to transition from splitting to tensile-shear composite failure,accompanied by surface spalling and debris splashing.Moreover,the thermal shock damage evolution and coupled failure mechanism of tested granite are discussed.The evolution of thermal shock damage with thermal shock cycle numbers shows an obvious S-shaped surface,featured by an exponential correlation with dynamic mechanical parameters.In addition,with increasing thermal shock temperature and cycles,granite mineral species barely change,but the length and width of thermal cracks increase significantly.The non-uniform expansion of minerals,thermal shock-induced cracking,and water-rock interaction are primary factors for deteriorating dynamic mechanical properties of granite under cyclic thermal shock.
基金Projects(52074259,52204132)supported by the National Natural Science Foundation of ChinaProject(104023002)supported by the Yunlong Lake Laboratory of Deep Underground Science and Engineering Project,China+2 种基金Project(BK20220157)supported by Natural Science Foundation of Jiangsu Province of ChinaProject(2023JJ40285)supported by Hunan Provincial Natural Science Foundation of ChinaProject(22B0469)supported by Scientific Research Foundation of Hunan Provincial Education Department,China。
文摘Rock-like specimens containing a joint with different inclination angles and roughness were prepared using 3D printing technology.Then,true triaxial compression loading experiments were conducted on those jointed specimens.The increase in roughness leads to an increase in the axial strength and peak strain.With the increasing inclination angle,the axial strength initially decreases from 30°to 60°and then increases from 60°to 90°.While the peak strain first rises from 30°to 45°and then declines from 45°to 90°.The variation in failure mode results from differences in lateral stress on the joints under different strike directions.Specimens with joint strike parallel to the intermediate principal stress predominantly showed matrix or matrix-joint mixed shear failure,whereas those parallel to the minimum principal stress exhibited matrix shear failure.The analysis results of acoustic emission signals indicate the crack number and shear crack percentage increase with the increasing roughness and first decrease(30°to 60°),then increase(60°to 90°)with the increasing inclination angle.The research results can provide some guidance for the design and support of underground engineering with jointed surrounding rock.
基金support received from the National Natural Science Foundation of China(Nos.52274145,52469019,and 52109119)the Guangxi Natural Science Foundation(No.2025GXNSFAA069165)the Chinese Postdoctoral Science Fund Project(No.2022M723408).
文摘After the excavation of deep mining tunnels and underground caverns,the stability of surrounding rock controlled by structural planes is prone to structural damage and even engineering disasters due to three-dimensional stress redistribution and multi-directional dynamic construction interference.However,the shear mechanical behavior,fracture evolution mechanism and precursor characteristics of rockmass under true triaxial stress and multi-directional coupling disturbance are not unclear.Therefore,this study carried out true triaxial shear tests on limestone intermittent structural planes under uni-,bi-and tri-directional coupling disturbances to analyze its mechanical behavior,fracture evolution mechanism and precursor characteristics.The results show that as the disturbance direction increase,the shear strength of limestone generally decreases,while the roughness of structural planes and the degree of anisotropy generally exhibit an increasing trend.The proportion of shear cracks on the structural plane increases with the increase of shear stress.The disturbance strain rate before failure shows a U-shaped trend.Near to disturbance failure,there were more high-energy and high-amplitude acoustic emission events near the structural plane,and b-value drops rapidly below 1,while lgN/b ratio increased to above 3.These findings provide experimental recognition and theoretical support for assessing the stability of rockmass under blasting excavation.
基金Projects(50374082,5071112018)supported by the National Natural Science Foundation of China
文摘Based on the high-purity single-crystal tungsten nanowire firstly prepared by the metal-catalyzed vapor-phase reaction method, molecular dynamics method was used to calculate tensile stress-strain curves and simulate microscopic deformation structures of the single-crystal tungsten nanowires with different crystal orientations of 〈100〉, 〈110〉and 〈111〉, in order to reveal the effect of crystal orientation on their tensile mechanical properties and failure mechanisms. Research results show that all of the stress-strain curves are classified into four stages： elastic stage, damage stage, yielding stage and failure stage, where 〈100〉orientation has a special hardening stage after yielding and two descending stages. The crystal orientation has little effect on elastic modulus but great effect on tensile strength, yielding strength and ductility, depending on different atomic surface energies and principal sliding planes. The calculated values of elastic modulus are in good agreement with the tested values of elastic modulus.
基金Project(U22A20603)supported by the National Natural Science Foundation of ChinaProject(2023YFC3008300)supported by the National Key Research and Development Program of China。
文摘To investigate the long-term stability of soft-hard interbedded rock masses with initial damage induced by earthquakes and periodic drying and wetting,this study prepared samples with different initial damage through cyclic loading and unloading(CLU)experiments followed by cyclic drying and wetting(CDW)experiments,and finally conducted creep experiments.The study analyzed the effects of initial damage on creep mechanical behavior,crack evolution,and explored failure precursor information,revealing the damage failure mechanisms.The results show that the structural characteristics of the rock mass control its macroscopic failure mode.Initial damage promotes microcrack development,influences the fracture mode,and increases the proportion of high-frequency(200−280 kHz)acoustic emission events during creep.Meanwhile,initial damage exacerbates creep characteristics,increasing the creep rate,shortening total creep failure time,and reducing long-term strength.The damage failure is attributed to:the generation of internal cracks and pores in the rock caused by CLU;mineral hydrolysis and expansion-contraction due to CDW,resulting in weakened intergranular cementation;and full development of cracks and pores under creep stress.Additionally,the deformation difference coefficient and the coefficient of variation of RA/AF values can serve as precursor indicators for creep failure.
基金sponsored by National Natural Science Foundation of China(Nos.52305146 and 52275165)Natural Science Foundation of Chongqing,China(No.cstb2022nscqmsx1290)+1 种基金the financial support from the Major Special Project for Technological Innovation and Application Development of Chongqing(No.CSTB2024TIAD-STX0015)the Key Laboratory Project of Shaanxi Province(No.2025SYS-SYSZD-064)。
文摘This study introduces electromagnetic dynamic self-piercing riveting(ED-SPR),an innovative technique that integrates electromagnetic riveting principles with static self-piercing riveting(S-SPR)for highperformance structural joints.A dedicated methodology and experimental apparatus for ED-SPR were systematically designed and validated.Quantitative comparative analyses between ED-SPR and S-SPR were conducted on three critical material combinations:CFRP/Al,low-strength steel HC340 LA/Al,and high-strength steel DP590/Al.Key findings demonstrate that the electromagnetic-driven process reduces installation resistance by 60%and achieves a 30%larger interlock distance at the joint base compared to S-SPR.These quantitative advantages directly contribute to an approximately 30%increase in load-bearing capacity and superior damage tolerance in ED-SPR joints,as evidenced by tensile-shear testing of single-lap joints.Furthermore,distinct failure modes were observed:ED-SPR joints exhibited top plate pull-out failure in CFRP/Al and DP590/Al configurations,contrasting with the predominant rivet pull-out failure in S-SPR counterparts.Surface morphology and damage evolution were characterized via scanning electron microscopy(SEM)on post-assembly and tensile-failed specimens.The study establishes a foundation for optimizing electromagnetic-driven riveting parameters to mitigate CFRP delamination and further enhance joint reliability in vehicle body and aircraft fuselage structures.
基金support of the National Natural Science Foundation of China(Grant Nos.52179116 and 51991392)the support of Key Deployment Projects of Chinese Academy of Sciences(Grant No.ZDRW-ZS-2021-3).
文摘Shield tunneling in saturated ground poses challenges due to the potential risk of ground collapse resulting from seepage force and inadequate support pressure.This study employed a laboratory model test and a theoretical validation to elucidate the mechanisms of face failure and subsequent ground collapse in saturated ground during slurry pressure-balanced shield(SPBS)tunneling operations.A slurry circulation system was developed to ensure steady shield tunneling and to replicate the phenomena of ground collapse.Investigations into shield tunneling parameters and ground responses,including soil pressure,pore water pressure,and surface subsidence,were conducted to understand the mechanisms of face failure and subsequent ground collapse.The theoretical solution for the critical collapse pressure of the tunnel face,based on the rotational failure mechanism,was validated through the comparison with the experimentally determined critical collapse pressure.The results indicate that:(1)appropriate adjustments of tunneling parameters are crucial for promoting filtercake formation,maintaining chamber pressure,and minimizing ground subsidence;(2)chamber pressure,soil pressure,pore water pressure,and ground subsidence are closely correlated with shield tunneling parameters and the formation of filter cake;(3)ground collapse follows a continuous failure mode due to the destruction of filtercake and the decrease in chamber pressure;(4)the soil pressure at the cutterhead is more sensitive to disturbances from shield tunneling than chamber pressure;and(5)experimentally determined critical collapse pressures is consistent with the theoretical solution of limit analysis.
基金Project supported by the National Key Research and Development Program of China(Grant No.2023YFA1609000)the National Natural Science Foundation of China(Grant Nos.U2341222,U2441248,12275061,and 12075069)。
文摘The failure mechanisms and structural damage of SiC MOSFETs induced by heavy ion irradiation were demonstrated.The findings reveal three degradation modes,depending on the drain voltage.At a relatively low voltage,the damage is triggered by the formation and activation of gate latent damage(LDs),with damage concentrated in the gate oxide.The second degradation mode involves permanent leakage current degradation,with damage progressively transitioning from the oxide to the SiC material as the drain voltage escalates.Ultimately,the device undergoes catastrophic burnout above certain voltages,characterized by the lattice temperature reaching the sublimation point of SiC,resulting in surface cavity and complete structural destruction.This paper presents a comprehensive investigation of SiC MOSFETs under heavy ion exposure,providing radiation resistance methods of SiC-based devices for aerospace applications.
文摘Self-piercing riveting(SPR)is a cold forming technique used to fasten together two or more sheets of materials with a rivet without the need to predrill a hole.The application of SPR in the automotive sector has become increasingly popular mainly due to the growing use of lightweight materials in transportation applications.However,SPR joining of these advanced light materials remains a challenge as these materials often lack a good combination of high strength and ductility to resist the large plastic deformation induced by the SPR process.In this paper,SPR joints of advanced materials and their corresponding failure mechanisms are discussed,aiming to provide the foundation for future improvement of SPR joint quality.This paper is divided into three major sections:1)joint failures focusing on joint defects originated from the SPR process and joint failure modes under different mechanical loading conditions,2)joint corrosion issues,and 3)joint optimisation via process parameters and advanced techniques.
基金Project(51904165)supported by the National Natural Science Foundation of ChinaProject(ZR2019QEE026)supported by the Shandong Provincial Natural Science Foundation,ChinaProject(ZR2019ZD13)supported by the Major Program of Shandong Provincial Natural Science Foundation,China。
文摘Lots of field investigations have proven that layer-crack structure usually appears during the excavation process of deep rock or coal mass.To provide experimental data for studying the formation mechanism of layer-crack structure,this study researches the influence of lateral pressure on the mechanical behavior of different rock types.Four rock types have been tested and the formation mechanism of macro-fracture surface is analyzed.Results indicate that the brittleness and burst proneness of rock or coal material are stronger than that of gypsum material due to the different mineral compositions and structures.When the lateral pressure is less than 10%uniaxial strength,the peak stress and elastic modulus increase with the increase of lateral pressure;but when the lateral pressure is larger than 10%uniaxial strength,the two parameters decrease slightly or keep steady.This is because when the lateral pressure reaches a certain value,local failure will be formed during the process of applying lateral pressure.Under the condition of low lateral pressure,the failure of the specimen is dominated by the tensile mechanism;under the condition of relatively high lateral pressure,the area of the specimen close to the free surface is tensile splitting failure,and the area far from the free surface is shear failure.
基金co-supported by National Basic Research Program of China, National Natural Science Foundation of China(No. 51075204)Aeronautical Science Foundation of China (No.2009ZB52028, No. 2012ZB52026)+1 种基金Research Fund for the Doctoral Program of Higher Education of China (No. 20070287039)NUAA Research Funding (No. NZ2012106)
文摘A new unified macro- and micro-mechanics failure analysis method for composite structures was developed in order to take the effects of composite micro structure into consideration. In this method, the macro stress distribution of composite structure was calculated by commercial finite element analysis software. According to the macro stress distribution, the damage point was searched and the micro-stress distribution was calculated by reformulated finite-volume direct averaging micromechanics （FVDAM）, which was a multi-scale finite element method for composite. The micro structure failure modes were estimated with the failure strength of constituents. A unidirectional composite plate with a circular hole in the center under two kinds of loads was analyzed with the traditional macro-mechanical failure analysis method and the unified macro- and micro-mechanics failure analysis method. The results obtained by the two methods are consistent, which show this new method＇s accuracy and efficiency.
文摘The mechanical behavior and failure mechanism of recycled semi-flexible pavement material were investigated by different scales method. The macroscopic mechanical behavior of samples was studied by static and dynamic splitting tensile tests on mechanics testing system(MTS). The mechanical analysis in micro scale was carried out by material image analysis method and finite element analysis system. The strains of recycled semi-flexible pavement material on samples surface and in each phase materials were obtained. The test results reveal that the performance of recovered asphalt binder was the major determinant on the structural stability of recycled semi-flexible pavement material. The asphalt binder with high viscoelasticity could delay the initial cracking time and reduce the residual strain under cyclic loading conditions. The failure possibility order of each phase in recycled semi-flexible pavement material was asphalt binder, reclaimed aggregate, cement paste and virgin aggregate.
