Tension-tension fatigue life tests on nano-grained delaminated low-carbon steel sheet under different fatigue loads are carried out to study the fatigue properties of the steel. The three-dimensional microstructures o...Tension-tension fatigue life tests on nano-grained delaminated low-carbon steel sheet under different fatigue loads are carried out to study the fatigue properties of the steel. The three-dimensional microstructures of the steel are observed by TEM. In addition, the morphology of the fatigue fracture of the specimen under different loads is observed by SEM. The results show that micro-cracks form on the weak interface of the nano-grained steel under low-stress conditions, which hinders the propagation of the main cracks and reduces the fatigue crack propagation rate, resulting in the extending fatigue life of the steel.展开更多
A method for the direct syntheses of partially and fully delaminated MWW zeolites is reported herein.Two organic amines were introduced into the hydrothermal synthetic system:hexamethyleneimine(HMI),which acted as the...A method for the direct syntheses of partially and fully delaminated MWW zeolites is reported herein.Two organic amines were introduced into the hydrothermal synthetic system:hexamethyleneimine(HMI),which acted as the structure-directing agent for the MWW layered structure;and dicyclohexylamine(DCHA),in the role of an in-situ delaminating agent.By varying the amount of DCHA,partially and fully delaminated MWW zeolites having two MWW structure layers and one single layer,respectively,were obtained.These were denoted as SCM-1(Sinopec Composite Material)and SCM-6,respectively.The delaminated materials possess ultra-large external surface areas,and the transmission electron microscopy images illustrated their layered nature.In the reaction of liquid phase benzene alkylation with ethylene,SCM-1,the double-layered MWW zeolite,exhibited far superior catalytic performance compared to zeolite MCM-22.展开更多
A macro-micro analytical approach for the anti-penetrating contact problem at the interfaces of the delamination in symmetrically cross-plied,fiber-reinforced rectangular laminates is presented in this paper.The lamin...A macro-micro analytical approach for the anti-penetrating contact problem at the interfaces of the delamination in symmetrically cross-plied,fiber-reinforced rectangular laminates is presented in this paper.The laminate is simply supported and subjected to a uniform transverse load with a through-width delamination buried at the center position.A contact factor is defined to characterize the contact effect and determined using the micro-mechanics of composite material.By analyzing the kinematics of nonlinear deformation at the interfaces of the delamination,the contact force is derived.Asymptotic solutions from perturbation analysis are presented.It is found that the deformation of the laminate involves a global deflection and a local buckling.The antipenetrating contact effects are characterized by the local buckling and are intrinsic properties of the laminates,relying only on the geometries of the delamination and the material properties.Parametric analyses show that the location and size of the contact areas and the distribution of the contact force are hardly affected by the aspect ratio.展开更多
The colloid of delaminated layered double hydroxides(LDHs), a new LDH-based catalyst, is described. The semi-heterogeneous delaminated colloidal MgPdA1-LDH, in which the total surface of catalytic site-bearing lamella...The colloid of delaminated layered double hydroxides(LDHs), a new LDH-based catalyst, is described. The semi-heterogeneous delaminated colloidal MgPdA1-LDH, in which the total surface of catalytic site-bearing lamellae was rendered accessible for chemical reactivity, showed excellent catalysis toward Suzuki reaction. The turnover frequency of this catalyst for Suzuki reaction between bromobenzene and phenylboronic acid is about 8000 h^-1.展开更多
In this paper, the postbuckling governing equations and the analytical expression of the energy release rates associated with delamination growth in a compression-loaded cylindrical shell are derived by using the vari...In this paper, the postbuckling governing equations and the analytical expression of the energy release rates associated with delamination growth in a compression-loaded cylindrical shell are derived by using the variational principle of moving boundary and the Griffith fracture criterion. The finite difference method is used to generate the postbuckling solutions of the delaminated cylindrical shells, and with these solutions, the values of the energy release rates are determined. In simulational examples, the effects of a wide range of parameters, such as delamination sizes and depths, boundary conditions, geometrical parameters, material properties and laminate stacking sequences on the energy release rates of axisymmetrical laminated cylindrical shells are intensively discussed.展开更多
The elasto-plastic postbuckling of fiber metal laminated beams with delamination and the energy release rate along the delamination front are discussed in this paper. Considering geometrical nonlinearity, thermal envi...The elasto-plastic postbuckling of fiber metal laminated beams with delamination and the energy release rate along the delamination front are discussed in this paper. Considering geometrical nonlinearity, thermal environment and geometrical initial imperfection, the incremental nonlinear equilibrium equations of delaminated fiber metal laminated beams are established, which are solved using the differential quadrature method and iterative method. Based on these, according to the J-integral theory, the elasto-plastic energy release rate is studied. The effects of some important parameters on the elasto-plastic postbuckling behavior and energy release rate of the aramid reinforced aluminum laminated beams are discussed in details.展开更多
The intracontinental subduction of a>200-km-long section of the Tajik-Tarim lithosphere beneath the Pamir Mountains is proposed to explain nearly 30 km of shortening in the Tajik fold-thrust belt and the Pamir upli...The intracontinental subduction of a>200-km-long section of the Tajik-Tarim lithosphere beneath the Pamir Mountains is proposed to explain nearly 30 km of shortening in the Tajik fold-thrust belt and the Pamir uplift.Seismic imaging revealed that the upper slab was scraped and that the lower slab had subducted to a depth of>150 km.These features constitute the tectonic complexity of the Pamirs,as well as the thermal subduction mechanism involved,which remains poorly understood.Hence,in this study,high-resolution three-dimensional(3D)kinematic modeling is applied to investigate the thermal structure and geometry of the subducting slab beneath the Pamirs.The modeled slab configuration reveals distinct along-strike variations,with a steeply dipping slab beneath the southern Pamirs,a more gently inclined slab beneath the northern Pamirs,and apparent upper slab termination at shallow depths beneath the Pamirs.The thermal field reveals a cold slab core after delamination,with temperatures ranging from 400℃to 800℃,enveloped by a hotter mantle reaching~1400℃.The occurrence of intermediate-depth earthquakes aligns primarily with colder slab regions,particularly near the slab tear-off below the southwestern Pamirs,indicating a strong correlation between slab temperature and seismicity.In contrast,the northern Pamirs exhibit reduced seismicity at depth,which is likely associated with thermal weakening and delamination.The central Pamirs show a significant thermal anomaly caused by a concave slab,where the coldest crust does not descend deeply,further suggesting crustal detachment or mechanical failure.The lateral asymmetry in slab temperature possibly explains the mechanism of lateral tearing and differential slab-mantle coupling.展开更多
Suspended graphene nanopores are widely used in nanofluidic devices,as the machined graphene defects can be downscaled to the angstrom scale.Our recent experimental results showed that the suspended graphene can becom...Suspended graphene nanopores are widely used in nanofluidic devices,as the machined graphene defects can be downscaled to the angstrom scale.Our recent experimental results showed that the suspended graphene can become delaminated from the edges of SiN nanopore under an applied electrical field,theoretical understanding of this process is still lacking.In this work,we analytically studied the voltage-induced blistering of suspended graphene using an energy approach.The external electric field induces accumulation of ions at the graphene-electrolyte interface,causing Maxwell stress resulting in bending and stretching of the graphene and blister formation.We theoretically derived the angle of the graphene blister to the SiN nanopore by energy approach.We found that once the vertical component of the Maxwell stress on the graphene at the perimeter of SiN nanopore ex-ceeds the van der Waals force between the graphene and substrate,the graphene starts to detach from the edges of SiN nanopore.We derived that the threshold voltage of single-layer graphene detachment is in order of 100 mV,which needs to be cautioned for electrical measurements of suspended graphene nanofluidic devices since the voltage amplitude is just in the range of voltage operation for typical electrochemical measurements.The threshold voltage increases as SiN nanopore becomes smaller and in-creases with the number of graphene layers.Our work theoretically describes the blister formation and delamination of graphene from its substrate nanopores.We expect this theory to be useful for optimizing and understanding the unexpected conduction phenomena observed in suspended graphene nanofluidic devices.展开更多
The mining height of a coal seam is a critical factor influencing the detachment,collapse,and formation of the collapse angle of the strata during strata movement.To clarify the mechanism by which mining height affect...The mining height of a coal seam is a critical factor influencing the detachment,collapse,and formation of the collapse angle of the strata during strata movement.To clarify the mechanism by which mining height affects strata movement characteristics,a physical model experiment was conducted based on the geological conditions of the Panel 122104 in Caojiatan Coal Mine in Shaanxi.The experiment examined strata movement at mining heights of 1 m and 10 m,identifying differences in detachment,collapse behavior,and collapse angles under these two conditions.The results indicate the following:Delamination range directly governs collapse patterns,with higher stress concentration accelerating delamination initiation and expanding affected zones.1 m mining height exhibits a“superposed fixed beam”structure with lower strength compared to the“fixed beam+cantilever beam”configuration under 10 m height.A model estimating collapse step shows 9.13%average error.Strata structure dictates collapse angle mechanisms:Pseudo-plastic deformation under 1 m height determines collapse angle through vertical tensile stress boundaries,whereas 10 m height exhibits brittle fracture behavior with collapse angles approximating fracture angles.Periodic collapse volume above working face directly correlates with mine pressure intensity and is positively correlated with the caving step distance,collapse angle,and caving range.These parameters show higher values under 10 m mining height,resulting in more pronounced mine pressure manifestations compared to 1 m conditions.展开更多
The high-temperature mechanical behaviors of Multi-Layer Composite Panels(MCP)and Corrugated Sandwich Panels(CSP)of Continuous Glass Fiber-Reinforced Polypropylene(CGFRPP)are critical for their application in aerospac...The high-temperature mechanical behaviors of Multi-Layer Composite Panels(MCP)and Corrugated Sandwich Panels(CSP)of Continuous Glass Fiber-Reinforced Polypropylene(CGFRPP)are critical for their application in aerospace fields,which have been rarely mentioned in previous studies.High-temperature quasi-static tensile and compression tests on CGFRPP MCP are conducted first.The results showed that the tensile and compression strength,stiffness,and tensile modulus of MCP decreased with increasing temperature.The Gibson model was found to be more suitable for predicting the high-temperature mechanical performance of MCP after comparing the calculated results of different theoretical models with experimental data.Secondly,hightemperature planar compression tests were conducted on the CGFRPP CSP,revealing that the main failure modes were corrugated core buckling and delamination between the face panel and core material,with delamination being intensified at higher temperatures.Therefore,we proposed a strength theoretical model that considers structural buckling failure and interface delamination failure,and introduced the influence factor to evaluate the effect of interface delamination on structural strength.展开更多
Geodynamic processes following the Indo-Eurasian plate collision remain a key research focus,and the Jinshajiang-Red River tectonic zone(JRTZ),situated along this collision boundary,provides critical insights into pos...Geodynamic processes following the Indo-Eurasian plate collision remain a key research focus,and the Jinshajiang-Red River tectonic zone(JRTZ),situated along this collision boundary,provides critical insights into post-collision tectonic evolution.In this study,we identify a lithological assemblage in the JRTZ,including amphibolite,granite gneiss,and migmatite.These rocks exhibit contrasting geochemical signatures,reflecting multiple source regions:asthenospheric mantle,lithospheric mantle,mafic lower and upper crust.Specifically,amphibolite(28.5 Ma)formed through the partial melting of OIB-like mantle source,whereas S-type granite gneiss(28.2 Ma)originated from the dehydration melting of metamorphosed sedimentary rocks.Amphibole monzonite(28.9 Ma)records the mixing of ancient crustal material with mantle-derived components,while migmatite(37.9 Ma)resulted from deep melting processes of metasedimentary rocks under shear conditions.We propose that the ongoing Indo-Eurasian convergence progressively thickened the crust,ultimately driving large-scale lithospheric delamination between the Eocene and Oligocene.This delamination triggered asthenospheric upwelling,which provided the thermal input required for widespread melting.This lithospheric delamination event started around 38-37 Ma and lasted at least until 28 Ma.展开更多
A comprehensive numerical investigation into mixed⁃mode delamination is presented in this study.It aims to assess the impact of thermal and friction effects through mixed⁃mode flexure crack propagation testing.Finite ...A comprehensive numerical investigation into mixed⁃mode delamination is presented in this study.It aims to assess the impact of thermal and friction effects through mixed⁃mode flexure crack propagation testing.Finite element analysis was employed to model the delamination process,incorporating a contact cohesive zone model.This model couples the traction⁃separation law,the contact law,and the Coulomb friction law simultaneously.The thermomechanical analysis in this study is performed using a sequentially coupled approach,implemented with the finite element software ABAQUS.The findings underscore the importance of this study.展开更多
The buckling behavior of a typical structure consisting of a micro constantan wire and a polymer membrane under coupled electrical-mechanical loading was studied. The phenomenon that the constantan wire delaminates fr...The buckling behavior of a typical structure consisting of a micro constantan wire and a polymer membrane under coupled electrical-mechanical loading was studied. The phenomenon that the constantan wire delaminates from the polymer membrane was observed after unloading. The interfacial toughness of the constantan wire and the polymer membrane was estimated. Moreover, several new instability modes of the constantan wire could be further triggered based on the buckle-driven delamination. After electrical loading and tensile loading, the constantan wire was likely to fracture based on buckling. After electrical loading and compressive loading, the constantan wire was easily folded at the top of the buckling region. On the occasion, the constantan wire buckled towards the inside of the polymer membrane under electrical-compressive loading. The mechanisms of these instability modes were analyzed.展开更多
The friction and wear behaviors of Inconel 690 flat against Si3Ni4 ball were investigated using a hydraulic fretting test rig equipped with a liquid container device. The loads of 20-80 N, reciprocating amplitudes of ...The friction and wear behaviors of Inconel 690 flat against Si3Ni4 ball were investigated using a hydraulic fretting test rig equipped with a liquid container device. The loads of 20-80 N, reciprocating amplitudes of 80-200 μm and two different environments （distilled water and hydrazine solution at temperatures from 25 to 90 ℃） were selected. The results show that the ratio of Ft/Fn is lower in distilled water than that in hydrazine solution at the same temperature in the slip regime. Both the ratio of Ft/Fn and wear volume gradually increase with increasing medium temperature under the given normal load and displacement amplitude. Besides the displacement amplitude and load, temperature also plays an important role for wear behavior of Inconel 690 material. The increase of temperature could reduce the concentration of dissolved oxygen, and promote the absorption reaction of hydrazine and dissolved oxygen. As a result, the oxidative corrosion rate is obviously lowered. Abrasive wear and delamination wear are the main mechanisms of Inconel 690 in distilled water. However, in hydrazine solution the cracks accompanied by abrasive wear and delamination wear are the main mechanisms.展开更多
On the basis ofa 2D 4-node Mindlin shell element method, a novel self-adapting delamination finite element method is presented, which is developed to model the delamination damage of composite laminates. In the method...On the basis ofa 2D 4-node Mindlin shell element method, a novel self-adapting delamination finite element method is presented, which is developed to model the delamination damage of composite laminates. In the method, the sublaminate elements are generated automatically when the delamination damage occurs or extends. Thus, the complex process and state of delamination damage can be simulated practically with high efficiency for both analysis and modeling. Based on the self-adapting delamination method, linear dynamic finite element damage analysis is performed to simulate the low-velocity impact damage process of three types of mixed woven composite laminates. Taking the frictional force among sublaminations during delaminating and the transverse normal stress into account, the analytical results are consistent with those of the experimental data.展开更多
The demand for highly porous yet transparent aerogels with mechanical flexibility and solar-thermal dual-regulation for energy-saving windows is significant but challenging.Herein,a delaminated aerogel film(DAF)is fab...The demand for highly porous yet transparent aerogels with mechanical flexibility and solar-thermal dual-regulation for energy-saving windows is significant but challenging.Herein,a delaminated aerogel film(DAF)is fabricated through filtration-induced delaminated gelation and ambient drying.The delaminated gelation process involves the assembly of fluorinated cellulose nanofiber(FCNF)at the solid-liquid interface between the filter and the filtrate during filtration,resulting in the formation of lamellar FCNF hydrogels with strong intra-plane and weak interlayer hydrogen bonding.By exchanging the solvents from water to hexane,the hydrogen bonding in the FCNF hydrogel is further enhanced,enabling the formation of the DAF with intra-layer mesopores upon ambient drying.The resulting aerogel film is lightweight and ultra-flexible,which pos-sesses desirable properties of high visible-light transmittance(91.0%),low thermal conductivity(33 mW m^(-1) K^(-1)),and high atmospheric-window emissivity(90.1%).Furthermore,the DAF exhibits reduced surface energy and exceptional hydrophobicity due to the presence of fluorine-containing groups,enhancing its durability and UV resistance.Consequently,the DAF has demonstrated its potential as solar-thermal regulatory cooling window materials capable of simultaneously providing indoor lighting,thermal insulation,and daytime radiative cooling under direct sunlight.Significantly,the enclosed space protected by the DAF exhibits a temperature reduction of 2.6℃ compared to that shielded by conventional architectural glass.展开更多
Based on the conventional compliance and area methods, a high precision method named the angle method is presented in this work. The interlaminar fracture toughness is determined by measurement of the load and the ben...Based on the conventional compliance and area methods, a high precision method named the angle method is presented in this work. The interlaminar fracture toughness is determined by measurement of the load and the bending angle at the loading point without measurement of the crack length, and the improvement of the conventional compliance method is made, which is more precise and can be used to general DCB specimen with unequal flexural stiffness of the cantilevers. The interlaminar fracture toughness in 0/ θ(θ =0°,30°,60°,90°) interfaces of two epoxy composites, one being the carbon fibre reinforced brittle matrix T300/4211, the other the carbon fibre reinforced tough matrix T300/3261, is measured by both compliance and angle methods, and the relationship between fracture toughness and the ply angle θ is obtained. It is found that the interlaminar fracture toughness is correlated with the type of matrix and the ply angles near the crack front.展开更多
40Ar-39Ar dating of albite from the Meishan and Taocun iron deposits yields plateau ages of 122.90±0.16 Ma and 124.89±0.30 Ma, and isochron ages of 122.60±0.16 Ma and 124.90±0.29 Ma, respectively. ...40Ar-39Ar dating of albite from the Meishan and Taocun iron deposits yields plateau ages of 122.90±0.16 Ma and 124.89±0.30 Ma, and isochron ages of 122.60±0.16 Ma and 124.90±0.29 Ma, respectively. Phlogopite from the Zhongshan-Gushan ore field has a plateau age of 126.7±0.17 Ma and an isochron age of 127.21±1.63 Ma. Analysis of regional geodynamic evolution of the middle-lower Yangtze River region suggests that the porphyry iron deposits were formed as a result of large-scale lithosphere delamination and strong sinistral strike-slip movement of the Tancheng Lujiang fault zone. The copper, molybdenum and gold deposit system in the middle-lower Yangtze River region was formed during the stress transition period of the eastern China continent.展开更多
Numerous theoretical and experimental efforts have been made to explain the dependence of the static wrink^h~g morphology on the materials＇ physical properties, whereas the dy- namic wrinkling process remains elusive...Numerous theoretical and experimental efforts have been made to explain the dependence of the static wrink^h~g morphology on the materials＇ physical properties, whereas the dy- namic wrinkling process remains elusive. In the present work, we design a wrinkling model consisting of a soft substrate and a graphene-like rigid thin film to investigate this dynamic process. The simulation shows that the whole wrinkling process includes three stages. At the incubation and wrinkling stages, the stress along the horizon direction of the soft substrate transfers to the stiff film. However, at the equilibrium stage, the stress of the rigid film slowly transfers back to the substrate although the total energy still decreases. It is found that the stress of the substrate concentrates at the top surface, especially at the trough, whereas the stress distribution of the film depends on direction. In the perpendicular direc- tion, the stress at the wave＇s equilibrium position surpasses that at the crest and trough and, oppositely, the stress concentrates at the crest and trough in the horizon direction. Present model reproduces both wrinkling and delamination patterns and can be a powerful tool to deeply understand the structure deformation of material induced by stress release.展开更多
The tribological properties of AICoCrFeNi and AICoCrFeNiTi0.5 high entropy alloys under gear oil and multiply alkylated cyclopentanes （MACs） lubrication condition have been studied. The equiaxed crystal structure of...The tribological properties of AICoCrFeNi and AICoCrFeNiTi0.5 high entropy alloys under gear oil and multiply alkylated cyclopentanes （MACs） lubrication condition have been studied. The equiaxed crystal structure of AICoCrFeNi alloy is obtained after heat-treatment. The AlCoCrFeNiTi0.5 alloy keeps dendrite structure. Under the gear oil with good lubrication action, AlCoCrFeNiTi0.5 alloy preserves better tribological properties than AICoCrFeNi alloy. The delamination and crack behaviors tend to occur in the grain boundary of AICoCrFeNi alloy and along the interdendrite region of AICoCrFeNiTi0.5 alloy. Under the MACs with relatively poor lubrication action, the applied load slightly influences the wear behavior of AICoCrFeNi alloy, but seriously impacts the wear mechanism of AlCoCrFeNiTi0.5 alloy. Compared with AlCoCrFeNi alloy, AlCoCrFeNiTi0.5 alloy keeps better wear-resistance at low applied load of 100 N, but preserves less wearresistance at high applied load of 200 N.展开更多
基金supported by the National Natural Science Foundation of China under grant No. 50371073
文摘Tension-tension fatigue life tests on nano-grained delaminated low-carbon steel sheet under different fatigue loads are carried out to study the fatigue properties of the steel. The three-dimensional microstructures of the steel are observed by TEM. In addition, the morphology of the fatigue fracture of the specimen under different loads is observed by SEM. The results show that micro-cracks form on the weak interface of the nano-grained steel under low-stress conditions, which hinders the propagation of the main cracks and reduces the fatigue crack propagation rate, resulting in the extending fatigue life of the steel.
文摘A method for the direct syntheses of partially and fully delaminated MWW zeolites is reported herein.Two organic amines were introduced into the hydrothermal synthetic system:hexamethyleneimine(HMI),which acted as the structure-directing agent for the MWW layered structure;and dicyclohexylamine(DCHA),in the role of an in-situ delaminating agent.By varying the amount of DCHA,partially and fully delaminated MWW zeolites having two MWW structure layers and one single layer,respectively,were obtained.These were denoted as SCM-1(Sinopec Composite Material)and SCM-6,respectively.The delaminated materials possess ultra-large external surface areas,and the transmission electron microscopy images illustrated their layered nature.In the reaction of liquid phase benzene alkylation with ethylene,SCM-1,the double-layered MWW zeolite,exhibited far superior catalytic performance compared to zeolite MCM-22.
基金supported by the National Natural Science Foundation of China(Nos.11172113 and 11032005)
文摘A macro-micro analytical approach for the anti-penetrating contact problem at the interfaces of the delamination in symmetrically cross-plied,fiber-reinforced rectangular laminates is presented in this paper.The laminate is simply supported and subjected to a uniform transverse load with a through-width delamination buried at the center position.A contact factor is defined to characterize the contact effect and determined using the micro-mechanics of composite material.By analyzing the kinematics of nonlinear deformation at the interfaces of the delamination,the contact force is derived.Asymptotic solutions from perturbation analysis are presented.It is found that the deformation of the laminate involves a global deflection and a local buckling.The antipenetrating contact effects are characterized by the local buckling and are intrinsic properties of the laminates,relying only on the geometries of the delamination and the material properties.Parametric analyses show that the location and size of the contact areas and the distribution of the contact force are hardly affected by the aspect ratio.
基金Supported by the National Natural Science Foundation of China(No.20476092)the Science Foundation of Taizhou University, China(No.09ZD12)
文摘The colloid of delaminated layered double hydroxides(LDHs), a new LDH-based catalyst, is described. The semi-heterogeneous delaminated colloidal MgPdA1-LDH, in which the total surface of catalytic site-bearing lamellae was rendered accessible for chemical reactivity, showed excellent catalysis toward Suzuki reaction. The turnover frequency of this catalyst for Suzuki reaction between bromobenzene and phenylboronic acid is about 8000 h^-1.
基金The project supported by the National Natural Science Foundation of China(10572049）
文摘In this paper, the postbuckling governing equations and the analytical expression of the energy release rates associated with delamination growth in a compression-loaded cylindrical shell are derived by using the variational principle of moving boundary and the Griffith fracture criterion. The finite difference method is used to generate the postbuckling solutions of the delaminated cylindrical shells, and with these solutions, the values of the energy release rates are determined. In simulational examples, the effects of a wide range of parameters, such as delamination sizes and depths, boundary conditions, geometrical parameters, material properties and laminate stacking sequences on the energy release rates of axisymmetrical laminated cylindrical shells are intensively discussed.
基金Project supported by the National Natural Science Foundation of China(No.11272117)
文摘The elasto-plastic postbuckling of fiber metal laminated beams with delamination and the energy release rate along the delamination front are discussed in this paper. Considering geometrical nonlinearity, thermal environment and geometrical initial imperfection, the incremental nonlinear equilibrium equations of delaminated fiber metal laminated beams are established, which are solved using the differential quadrature method and iterative method. Based on these, according to the J-integral theory, the elasto-plastic energy release rate is studied. The effects of some important parameters on the elasto-plastic postbuckling behavior and energy release rate of the aramid reinforced aluminum laminated beams are discussed in details.
基金the Chinese Academy of Sciences Pioneer Hundred Talents Program and the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0708)supported by a MEXT(Ministry of Education,Culture,Sports,Science and Technology)KAKENHI(Grants-in-Aid for Scientific Research)grant(Grant No.21H05203)Kobe University Strategic International Collaborative Research Grant(Type B Fostering Joint Research).
文摘The intracontinental subduction of a>200-km-long section of the Tajik-Tarim lithosphere beneath the Pamir Mountains is proposed to explain nearly 30 km of shortening in the Tajik fold-thrust belt and the Pamir uplift.Seismic imaging revealed that the upper slab was scraped and that the lower slab had subducted to a depth of>150 km.These features constitute the tectonic complexity of the Pamirs,as well as the thermal subduction mechanism involved,which remains poorly understood.Hence,in this study,high-resolution three-dimensional(3D)kinematic modeling is applied to investigate the thermal structure and geometry of the subducting slab beneath the Pamirs.The modeled slab configuration reveals distinct along-strike variations,with a steeply dipping slab beneath the southern Pamirs,a more gently inclined slab beneath the northern Pamirs,and apparent upper slab termination at shallow depths beneath the Pamirs.The thermal field reveals a cold slab core after delamination,with temperatures ranging from 400℃to 800℃,enveloped by a hotter mantle reaching~1400℃.The occurrence of intermediate-depth earthquakes aligns primarily with colder slab regions,particularly near the slab tear-off below the southwestern Pamirs,indicating a strong correlation between slab temperature and seismicity.In contrast,the northern Pamirs exhibit reduced seismicity at depth,which is likely associated with thermal weakening and delamination.The central Pamirs show a significant thermal anomaly caused by a concave slab,where the coldest crust does not descend deeply,further suggesting crustal detachment or mechanical failure.The lateral asymmetry in slab temperature possibly explains the mechanism of lateral tearing and differential slab-mantle coupling.
基金supported by the National Natural Science Foundation of China(Grant Nos.12075191,12388101,and 12241201)Fundamental Research Funds for the Central Universities(Grant No.D5000230373)Innovation Capability Support Program of Shaanxi(Grant No.2024RS-CXTD-15).
文摘Suspended graphene nanopores are widely used in nanofluidic devices,as the machined graphene defects can be downscaled to the angstrom scale.Our recent experimental results showed that the suspended graphene can become delaminated from the edges of SiN nanopore under an applied electrical field,theoretical understanding of this process is still lacking.In this work,we analytically studied the voltage-induced blistering of suspended graphene using an energy approach.The external electric field induces accumulation of ions at the graphene-electrolyte interface,causing Maxwell stress resulting in bending and stretching of the graphene and blister formation.We theoretically derived the angle of the graphene blister to the SiN nanopore by energy approach.We found that once the vertical component of the Maxwell stress on the graphene at the perimeter of SiN nanopore ex-ceeds the van der Waals force between the graphene and substrate,the graphene starts to detach from the edges of SiN nanopore.We derived that the threshold voltage of single-layer graphene detachment is in order of 100 mV,which needs to be cautioned for electrical measurements of suspended graphene nanofluidic devices since the voltage amplitude is just in the range of voltage operation for typical electrochemical measurements.The threshold voltage increases as SiN nanopore becomes smaller and in-creases with the number of graphene layers.Our work theoretically describes the blister formation and delamination of graphene from its substrate nanopores.We expect this theory to be useful for optimizing and understanding the unexpected conduction phenomena observed in suspended graphene nanofluidic devices.
文摘The mining height of a coal seam is a critical factor influencing the detachment,collapse,and formation of the collapse angle of the strata during strata movement.To clarify the mechanism by which mining height affects strata movement characteristics,a physical model experiment was conducted based on the geological conditions of the Panel 122104 in Caojiatan Coal Mine in Shaanxi.The experiment examined strata movement at mining heights of 1 m and 10 m,identifying differences in detachment,collapse behavior,and collapse angles under these two conditions.The results indicate the following:Delamination range directly governs collapse patterns,with higher stress concentration accelerating delamination initiation and expanding affected zones.1 m mining height exhibits a“superposed fixed beam”structure with lower strength compared to the“fixed beam+cantilever beam”configuration under 10 m height.A model estimating collapse step shows 9.13%average error.Strata structure dictates collapse angle mechanisms:Pseudo-plastic deformation under 1 m height determines collapse angle through vertical tensile stress boundaries,whereas 10 m height exhibits brittle fracture behavior with collapse angles approximating fracture angles.Periodic collapse volume above working face directly correlates with mine pressure intensity and is positively correlated with the caving step distance,collapse angle,and caving range.These parameters show higher values under 10 m mining height,resulting in more pronounced mine pressure manifestations compared to 1 m conditions.
基金co-supported by the National Natural Science Foundation of China(Nos.12372127,12202085,12302464)the Fundamental Research Funds for the Central Universities,China(No.2024CDJXY009)+1 种基金the Chongqing Outstanding Youth Fund,China(No.CSTB2024NSCQ-JQX0028)the Chongqing Natural Science Foundation,China(Nos.cstc2021ycjh-bgzxm0117,CSTB2022NSCQ-MSX0608)。
文摘The high-temperature mechanical behaviors of Multi-Layer Composite Panels(MCP)and Corrugated Sandwich Panels(CSP)of Continuous Glass Fiber-Reinforced Polypropylene(CGFRPP)are critical for their application in aerospace fields,which have been rarely mentioned in previous studies.High-temperature quasi-static tensile and compression tests on CGFRPP MCP are conducted first.The results showed that the tensile and compression strength,stiffness,and tensile modulus of MCP decreased with increasing temperature.The Gibson model was found to be more suitable for predicting the high-temperature mechanical performance of MCP after comparing the calculated results of different theoretical models with experimental data.Secondly,hightemperature planar compression tests were conducted on the CGFRPP CSP,revealing that the main failure modes were corrugated core buckling and delamination between the face panel and core material,with delamination being intensified at higher temperatures.Therefore,we proposed a strength theoretical model that considers structural buckling failure and interface delamination failure,and introduced the influence factor to evaluate the effect of interface delamination on structural strength.
基金supported by the National Natural Science Foundation of China(Grant No.42472181)the National Key Research and Development Program of China(Grant No.2021YFA0719000)CNPC Innovation Fund(Grant No.2021DQ02-0103).
文摘Geodynamic processes following the Indo-Eurasian plate collision remain a key research focus,and the Jinshajiang-Red River tectonic zone(JRTZ),situated along this collision boundary,provides critical insights into post-collision tectonic evolution.In this study,we identify a lithological assemblage in the JRTZ,including amphibolite,granite gneiss,and migmatite.These rocks exhibit contrasting geochemical signatures,reflecting multiple source regions:asthenospheric mantle,lithospheric mantle,mafic lower and upper crust.Specifically,amphibolite(28.5 Ma)formed through the partial melting of OIB-like mantle source,whereas S-type granite gneiss(28.2 Ma)originated from the dehydration melting of metamorphosed sedimentary rocks.Amphibole monzonite(28.9 Ma)records the mixing of ancient crustal material with mantle-derived components,while migmatite(37.9 Ma)resulted from deep melting processes of metasedimentary rocks under shear conditions.We propose that the ongoing Indo-Eurasian convergence progressively thickened the crust,ultimately driving large-scale lithospheric delamination between the Eocene and Oligocene.This delamination triggered asthenospheric upwelling,which provided the thermal input required for widespread melting.This lithospheric delamination event started around 38-37 Ma and lasted at least until 28 Ma.
文摘A comprehensive numerical investigation into mixed⁃mode delamination is presented in this study.It aims to assess the impact of thermal and friction effects through mixed⁃mode flexure crack propagation testing.Finite element analysis was employed to model the delamination process,incorporating a contact cohesive zone model.This model couples the traction⁃separation law,the contact law,and the Coulomb friction law simultaneously.The thermomechanical analysis in this study is performed using a sequentially coupled approach,implemented with the finite element software ABAQUS.The findings underscore the importance of this study.
基金Projects(2010CB631005,2011CB606105)support by the National Basic Research Program of ChinaProjects(11232008,91216301,11227801,11172151)supported by the National Natural Science Foundation of ChinaProject supported by Tsinghua University Initiative Scientific Research Program
文摘The buckling behavior of a typical structure consisting of a micro constantan wire and a polymer membrane under coupled electrical-mechanical loading was studied. The phenomenon that the constantan wire delaminates from the polymer membrane was observed after unloading. The interfacial toughness of the constantan wire and the polymer membrane was estimated. Moreover, several new instability modes of the constantan wire could be further triggered based on the buckle-driven delamination. After electrical loading and tensile loading, the constantan wire was likely to fracture based on buckling. After electrical loading and compressive loading, the constantan wire was easily folded at the top of the buckling region. On the occasion, the constantan wire buckled towards the inside of the polymer membrane under electrical-compressive loading. The mechanisms of these instability modes were analyzed.
基金Project(51075342)supported by the National Natural Science Foundation of China
文摘The friction and wear behaviors of Inconel 690 flat against Si3Ni4 ball were investigated using a hydraulic fretting test rig equipped with a liquid container device. The loads of 20-80 N, reciprocating amplitudes of 80-200 μm and two different environments （distilled water and hydrazine solution at temperatures from 25 to 90 ℃） were selected. The results show that the ratio of Ft/Fn is lower in distilled water than that in hydrazine solution at the same temperature in the slip regime. Both the ratio of Ft/Fn and wear volume gradually increase with increasing medium temperature under the given normal load and displacement amplitude. Besides the displacement amplitude and load, temperature also plays an important role for wear behavior of Inconel 690 material. The increase of temperature could reduce the concentration of dissolved oxygen, and promote the absorption reaction of hydrazine and dissolved oxygen. As a result, the oxidative corrosion rate is obviously lowered. Abrasive wear and delamination wear are the main mechanisms of Inconel 690 in distilled water. However, in hydrazine solution the cracks accompanied by abrasive wear and delamination wear are the main mechanisms.
基金National Natural Science Foundation of China (50073002)
文摘On the basis ofa 2D 4-node Mindlin shell element method, a novel self-adapting delamination finite element method is presented, which is developed to model the delamination damage of composite laminates. In the method, the sublaminate elements are generated automatically when the delamination damage occurs or extends. Thus, the complex process and state of delamination damage can be simulated practically with high efficiency for both analysis and modeling. Based on the self-adapting delamination method, linear dynamic finite element damage analysis is performed to simulate the low-velocity impact damage process of three types of mixed woven composite laminates. Taking the frictional force among sublaminations during delaminating and the transverse normal stress into account, the analytical results are consistent with those of the experimental data.
基金The authors are grateful for the financial support from the National Natural Science Foundation of China(Grant Nos.52273067,52122303,52233006)the Fundamental Research Funds for the Central Universities(Grant No.2232023A-03)the Shuguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission(23SG29).
文摘The demand for highly porous yet transparent aerogels with mechanical flexibility and solar-thermal dual-regulation for energy-saving windows is significant but challenging.Herein,a delaminated aerogel film(DAF)is fabricated through filtration-induced delaminated gelation and ambient drying.The delaminated gelation process involves the assembly of fluorinated cellulose nanofiber(FCNF)at the solid-liquid interface between the filter and the filtrate during filtration,resulting in the formation of lamellar FCNF hydrogels with strong intra-plane and weak interlayer hydrogen bonding.By exchanging the solvents from water to hexane,the hydrogen bonding in the FCNF hydrogel is further enhanced,enabling the formation of the DAF with intra-layer mesopores upon ambient drying.The resulting aerogel film is lightweight and ultra-flexible,which pos-sesses desirable properties of high visible-light transmittance(91.0%),low thermal conductivity(33 mW m^(-1) K^(-1)),and high atmospheric-window emissivity(90.1%).Furthermore,the DAF exhibits reduced surface energy and exceptional hydrophobicity due to the presence of fluorine-containing groups,enhancing its durability and UV resistance.Consequently,the DAF has demonstrated its potential as solar-thermal regulatory cooling window materials capable of simultaneously providing indoor lighting,thermal insulation,and daytime radiative cooling under direct sunlight.Significantly,the enclosed space protected by the DAF exhibits a temperature reduction of 2.6℃ compared to that shielded by conventional architectural glass.
文摘Based on the conventional compliance and area methods, a high precision method named the angle method is presented in this work. The interlaminar fracture toughness is determined by measurement of the load and the bending angle at the loading point without measurement of the crack length, and the improvement of the conventional compliance method is made, which is more precise and can be used to general DCB specimen with unequal flexural stiffness of the cantilevers. The interlaminar fracture toughness in 0/ θ(θ =0°,30°,60°,90°) interfaces of two epoxy composites, one being the carbon fibre reinforced brittle matrix T300/4211, the other the carbon fibre reinforced tough matrix T300/3261, is measured by both compliance and angle methods, and the relationship between fracture toughness and the ply angle θ is obtained. It is found that the interlaminar fracture toughness is correlated with the type of matrix and the ply angles near the crack front.
基金the State Basic Research Program of China(Grant No.G1999043206)
文摘40Ar-39Ar dating of albite from the Meishan and Taocun iron deposits yields plateau ages of 122.90±0.16 Ma and 124.89±0.30 Ma, and isochron ages of 122.60±0.16 Ma and 124.90±0.29 Ma, respectively. Phlogopite from the Zhongshan-Gushan ore field has a plateau age of 126.7±0.17 Ma and an isochron age of 127.21±1.63 Ma. Analysis of regional geodynamic evolution of the middle-lower Yangtze River region suggests that the porphyry iron deposits were formed as a result of large-scale lithosphere delamination and strong sinistral strike-slip movement of the Tancheng Lujiang fault zone. The copper, molybdenum and gold deposit system in the middle-lower Yangtze River region was formed during the stress transition period of the eastern China continent.
基金the High Performance Computing Center of Tianjin University, China and the National Natural Science Foundation of China （No.91127046, No.21274107, and No.21474075）.
文摘Numerous theoretical and experimental efforts have been made to explain the dependence of the static wrink^h~g morphology on the materials＇ physical properties, whereas the dy- namic wrinkling process remains elusive. In the present work, we design a wrinkling model consisting of a soft substrate and a graphene-like rigid thin film to investigate this dynamic process. The simulation shows that the whole wrinkling process includes three stages. At the incubation and wrinkling stages, the stress along the horizon direction of the soft substrate transfers to the stiff film. However, at the equilibrium stage, the stress of the rigid film slowly transfers back to the substrate although the total energy still decreases. It is found that the stress of the substrate concentrates at the top surface, especially at the trough, whereas the stress distribution of the film depends on direction. In the perpendicular direc- tion, the stress at the wave＇s equilibrium position surpasses that at the crest and trough and, oppositely, the stress concentrates at the crest and trough in the horizon direction. Present model reproduces both wrinkling and delamination patterns and can be a powerful tool to deeply understand the structure deformation of material induced by stress release.
基金the financial support from the National Natural Science Foundation of China(No.51271151)the Program of Introducing Talents of Discipline to Universities(No.B08040)
文摘The tribological properties of AICoCrFeNi and AICoCrFeNiTi0.5 high entropy alloys under gear oil and multiply alkylated cyclopentanes （MACs） lubrication condition have been studied. The equiaxed crystal structure of AICoCrFeNi alloy is obtained after heat-treatment. The AlCoCrFeNiTi0.5 alloy keeps dendrite structure. Under the gear oil with good lubrication action, AlCoCrFeNiTi0.5 alloy preserves better tribological properties than AICoCrFeNi alloy. The delamination and crack behaviors tend to occur in the grain boundary of AICoCrFeNi alloy and along the interdendrite region of AICoCrFeNiTi0.5 alloy. Under the MACs with relatively poor lubrication action, the applied load slightly influences the wear behavior of AICoCrFeNi alloy, but seriously impacts the wear mechanism of AlCoCrFeNiTi0.5 alloy. Compared with AlCoCrFeNi alloy, AlCoCrFeNiTi0.5 alloy keeps better wear-resistance at low applied load of 100 N, but preserves less wearresistance at high applied load of 200 N.
