Fiber-reinforced composites are an ideal material for the lightweight design of aerospace structures. Especially in recent years, with the rapid development of composite additive manufacturing technology, the design o...Fiber-reinforced composites are an ideal material for the lightweight design of aerospace structures. Especially in recent years, with the rapid development of composite additive manufacturing technology, the design optimization of variable stiffness of fiber-reinforced composite laminates has attracted widespread attention from scholars and industry. In these aerospace composite structures, numerous cutout panels and shells serve as access points for maintaining electrical, fuel, and hydraulic systems. The traditional fiber-reinforced composite laminate subtractive drilling manufacturing inevitably faces the problems of interlayer delamination, fiber fracture, and burr of the laminate. Continuous fiber additive manufacturing technology offers the potential for integrated design optimization and manufacturing with high structural performance. Considering the integration of design and manufacturability in continuous fiber additive manufacturing, the paper proposes linear and nonlinear filtering strategies based on the Normal Distribution Fiber Optimization (NDFO) material interpolation scheme to overcome the challenge of discrete fiber optimization results, which are difficult to apply directly to continuous fiber additive manufacturing. With minimizing structural compliance as the objective function, the proposed approach provides a strategy to achieve continuity of discrete fiber paths in the variable stiffness design optimization of composite laminates with regular and irregular holes. In the variable stiffness design optimization model, the number of candidate fiber laying angles in the NDFO material interpolation scheme is considered as design variable. The sensitivity information of structural compliance with respect to the number of candidate fiber laying angles is obtained using the analytical sensitivity analysis method. Based on the proposed variable stiffness design optimization method for complex perforated composite laminates, the numerical examples consider the variable stiffness design optimization of typical non-perforated and perforated composite laminates with circular, square, and irregular holes, and systematically discuss the number of candidate discrete fiber laying angles, discrete fiber continuous filtering strategies, and filter radius on structural compliance, continuity, and manufacturability. The optimized discrete fiber angles of variable stiffness laminates are converted into continuous fiber laying paths using a streamlined process for continuous fiber additive manufacturing. Meanwhile, the optimized non-perforated and perforated MBB beams after discrete fiber continuous treatment, are manufactured using continuous fiber co-extrusion additive manufacturing technology to verify the effectiveness of the variable stiffness fiber optimization framework proposed in this paper.展开更多
This study aims to investigate the propagation of harmonic waves in nonlocal magneto-electro-elastic(MEE)laminated composites with interface stress imperfections using an analytical approach.The pseudo-Stroh formulati...This study aims to investigate the propagation of harmonic waves in nonlocal magneto-electro-elastic(MEE)laminated composites with interface stress imperfections using an analytical approach.The pseudo-Stroh formulation and nonlocal theory proposed by Eringen were adopted to derive the propagator matrix for each layer.Both the propagator and interface matrices were formulated to determine the recursive fields.Subsequently,the dispersion equation was obtained by imposing traction-free and magneto-electric circuit open boundary conditions on the top and bottom surfaces of the plate.Dispersion curves,mode shapes,and natural frequencies were calculated for sandwich plates composed of BaTiO3 and CoFe2O4.Numerical simulations revealed that both interface stress and the nonlocal effect influenced the tuning of the dispersion curve and mode shape for the given layup.The nonlocal effect caused a significant decrease in the dispersion curves,particularly in the high-frequency regions.Additionally,compared to the nonlocal effect,the interface stress exerted a greater influence on the mode shapes.The generalized analytical framework developed in this study provides an effective tool for both the theoretical analysis and practical design of MEE composite laminates.展开更多
A partial-periodic model is proposed for predicting structural properties of composite laminate structures.The partial-periodic model contains periodic boundary conditions in one direction or two directions,and free b...A partial-periodic model is proposed for predicting structural properties of composite laminate structures.The partial-periodic model contains periodic boundary conditions in one direction or two directions,and free boundary condition in other directions.In the present study,partial-periodic model for composite laminate beam structures is particularly studied.Three-point bending experiments for laminate beam specimens with different laying parameters are firstly used to verify the present partial-periodic model.In addition,a detailed finite element method(FEM)model is also used to further quantitatively compare with the present partial-periodic model for composite laminate beams with different laying parameters.The results indicate that the proposed partial-periodic model is capable of providing accurate predictions in most cases.The computational time cost of the proposed partial-periodic model is much lower than that of the detailed FEM model as well.Convergence studies are also conducted for the present partial-periodic model with different model sizes and element sizes.It is suggested that the proposed partial-periodic model has the potential to be used as an accurate and time-saving tool for predicting the structural properties of composite laminate beam structures.展开更多
The remarkable mechanical properties exhibited by laminated structures have generated significant in-terest in the realm of additively manufactured laminated high-entropy alloys(HEAs).Despite this bur-geoning interest...The remarkable mechanical properties exhibited by laminated structures have generated significant in-terest in the realm of additively manufactured laminated high-entropy alloys(HEAs).Despite this bur-geoning interest,the nexus between process,structure,and properties within laminated HEAs remains largely uncharted.There is a vast space for investigating the effect of the typical heterogeneous interface on the macroscopic mechanical properties.This study focuses on the influence of the characteristic het-erogeneous interface on macroscopic mechanical properties of laminated HEAs,particularly anisotropy.Using the 3D-printed Fe_(50)Mn_(30)Co_(10)Cr_(10)-CoCrNi HEA as a model,we investigate the impact of interface geometry on mechanical characteristics.Tensile tests show that the reduced interface spacing increases yield strength.This laminated HEA displays significant anisotropy in strength and ductility,depending on the loading direction relative to the interface.Electron microscopic observations suggest that finer layer spacing enhances interface and dislocation strengthening,increasing yield strength.Anisotropic behaviors are confirmed to be mediated by interface orientation,explained in terms of deformation compatibility and crack development at the interface.This research offers fundamental insights into the relationship between heterogeneous interfaces and the mechanical properties in laminated HEAs.The knowledge is vital for designing,fabricating,and optimizing laminated HEAs through additive manufacturing,advancing their engineering applications.展开更多
Three types of Al/Al−27%Si laminated composites,each containing 22%Si,were fabricated via hot pressing and hot rolling.The microstructures,mechanical properties and thermo-physical properties of these composites were ...Three types of Al/Al−27%Si laminated composites,each containing 22%Si,were fabricated via hot pressing and hot rolling.The microstructures,mechanical properties and thermo-physical properties of these composites were investigated.The results demonstrated that the three laminated composites exhibited similar microstructural features,characterized by well-bonded interfaces between the Al layer and the Al−27%Si alloy layer.The tensile and flexural strengths of the composites were significantly higher than those of both Al−22%Si and Al−27%Si alloys.These strengths increased gradually with decreasing the layer thickness,reaching peak values of 222.5 and 407.4 MPa,respectively.Crack deflection was observed in the cross-sections of the bending fracture surfaces,which contributed to the enhanced strength and toughness.In terms of thermo-physical properties,the thermal conductivity of the composites was lower than that of Al−22%Si and Al−27%Si alloys.The minimum reductions in thermal conductivity were 6.8%and 0.9%for the T3 laminated composite,respectively.Additionally,the coefficient of thermal expansion of the composites was improved,exhibiting varying temperature-dependent behaviors.展开更多
In Ti-Al laminated composites,cracks nucleate preferentially at the Al_(3)Ti layer,but the inhibitory effect of Al_(3)Ti on crack extension is ignored.Interestingly,by combining experiment and phase-field crystal simu...In Ti-Al laminated composites,cracks nucleate preferentially at the Al_(3)Ti layer,but the inhibitory effect of Al_(3)Ti on crack extension is ignored.Interestingly,by combining experiment and phase-field crystal simulation,we found that the micrometer Al_(3)Ti particles in the diffusion layer play the role of crack deflection and passivation,which is attributed to the lattice distortion induced by Al_(3)Ti consumes the energy of the crack in extension.In addition,it is found that the growth process of Al_(3)Ti is divided into two stages:nucleation stage and growth stage.Compared with the growth stage,the Al_(3)Ti grains in the nucleation stage are finer in the growth layer.Finer grains show better crack deflection and avoid stress concentration.展开更多
Al/Cu laminate composite was fabricated based on hot press sintering using Cu sheet and Al powders as raw materials.The effects of sintering parameters on interfacial structure and mechanical properties were investiga...Al/Cu laminate composite was fabricated based on hot press sintering using Cu sheet and Al powders as raw materials.The effects of sintering parameters on interfacial structure and mechanical properties were investigated.The results revealed that a uniform Al/Cu interface with excellent bonding quality was achieved.The thickness of intermetallic compounds(IMCs)reached 33.88μm after sintering at 620℃for 2 h,whereas it was only 14.88μm when sintered at 600℃for 1 h.AlCu phase was developed through the reaction between Al4Cu9 and Al2Cu with prolonging sintering time,and an amorphous oxide strip formed at AlCu/Al4Cu9 interface.Both the grain morphology and interfacial structure affected the tensile strength of Al/Cu laminate,whereas the mode of tensile fracture strongly relied on the interfacial bonding strength.The highest tensile strength of 151.1 MPa and bonding strength of 93.7 MPa were achieved after sintering at 600℃for 1 h.展开更多
Fiber Metal Laminates(FMLs),as high-performance composite materials,demonstrate exceptional potential in a wide range of applications,such as aeronautical and astronautical industries.However,the traditional cured FML...Fiber Metal Laminates(FMLs),as high-performance composite materials,demonstrate exceptional potential in a wide range of applications,such as aeronautical and astronautical industries.However,the traditional cured FMLs possess complex interlayer stresses and low forming limits,restricting further promotion and application of FMLs.Low-constraint FMLs exhibit a lower forming resistance and better formability due to no curing during the forming process;however,the formation mechanism and response are not clear.This paper presents the Forming Limit Diagram(FLD)of low-constraint GLARE(glass fiber reinforced aluminum laminates)based on the forming limit test,and compares it with the conventionally cured laminates to evaluate the differences in the forming limit.In addition,combined with the analysis of failure mechanism and micro-deformation mechanism of specimens,the influence of different temperatures(20–80℃)and forming states(width)on the deformation performance of laminates is further explored.The results reveal that the forming limit curve of low-constraint laminates shifts up with the increase of temperature,the forming limit initially increases with the increase of width,then followed by a gradual decrease,and the maximum principal strain of low-constraint laminates is increased by 29% at 80℃ compared to 20℃.The cured laminate has a principal strain range of 0–0.02,while the low-constraint laminates have a principal strain range of 0.03–0.14.Compared with cured laminates,low-constraint laminates possess a higher forming limit due to the improvement in deformable degree between layers by resin flow and fiber slippage,which enhances their formability.This study is expected to serve as a reference for establishing forming limit criteria and optimizing forming schemes for low-constraint laminates.展开更多
The Cu/1010 steel bimetal laminated composites(BLCs)were rolled to different thicknesses to investigate the effect of rolling direction and reduction on the microstructure evolution and mechanical properties.The diffe...The Cu/1010 steel bimetal laminated composites(BLCs)were rolled to different thicknesses to investigate the effect of rolling direction and reduction on the microstructure evolution and mechanical properties.The difference of mechanical properties between the Cu and 1010 steel causes different thickness reductions,percentage spread,and cladding ratios.The formation of strong texture induces larger strength of the rolled samples,and as the volume fraction of 1010 steel is larger in Route-A,its strength is consistently greater than that in Route-B.The obstruction of interface to crystal and dislocation slip results in the formation of interface distortion,inducing dislocation density gradient when the rolling reduction is low in Route-A.The slip planes of the Cu and 1010 steel are more prone to suffer the normal strain,while the shear strain of other crystal planes is obviously larger than the normal strain under rolling load near the interface.展开更多
Plasma electrolytic oxidation(PEO)coatings were prepared on Al−Mg laminated macro composites(LMCs)using both unipolar and bipolar waveforms in an appropriate electrolyte for both aluminum and magnesium alloys.The tech...Plasma electrolytic oxidation(PEO)coatings were prepared on Al−Mg laminated macro composites(LMCs)using both unipolar and bipolar waveforms in an appropriate electrolyte for both aluminum and magnesium alloys.The techniques of FESEM/EDS,grazing incident beam X-ray diffraction(GIXRD),and electrochemical methods of potentiodynamic polarization and electrochemical impedance spectroscopy(EIS)were used to characterize the coatings.The results revealed that the coatings produced using the bipolar waveform exhibited lower porosity and higher thickness than those produced using the unipolar one.The corrosion performance of the specimens’cut edge was investigated using EIS after 1,8,and 12 h of immersion in a 3.5 wt.%NaCl solution.It was observed that the coating produced using the bipolar waveform demonstrated the highest corrosion resistance after 12 h of immersion,with an estimated corrosion resistance of 5.64 kΩ·cm^(2),which was approximately 3 times higher than that of the unipolar coating.Notably,no signs of galvanic corrosion were observed in the LMCs,and only minor corrosion attacks were observed on the magnesium layer in some areas.展开更多
Longitudinal seismic performance is a critical aspect to be considered during the tunnel design process,in addition to cross-sectional considerations.The present study proposed using a laminated shear energy dissipati...Longitudinal seismic performance is a critical aspect to be considered during the tunnel design process,in addition to cross-sectional considerations.The present study proposed using a laminated shear energy dissipation(LSED)structure to achieve effective longitudinal seismic design.The proposed structure consists of thin steel plates and alternately bonded layers of rubber,which can be installed around the periphery of the secondary lining.This configuration guarantees that the tunnels will exhibit optimal axial deformation capacity and robust rigid resistance to circumferential compression from the surrounding rock.To evaluate the impact of the LSED structure on the longitudinal seismic performance of the tunnel,a fine numerical model of the LSED structureetunnel liningesurrounding rock system was developed using finite element simulation.The evaluation criteria include maximum principal stress and strain energy.The seismic response of the tunnel with the LSED structure exhibited a notable reduction of over 40%in terms of seismic attenuation rate when subjected to the Trinidad seismic wave compared to the tunnel without the LSED structure.Furthermore,the aseismic mechanism of the proposed LSED structure is discussed,considering both internal factors such as the rubber shear modulus,steel plate dimensions,and number and location of structures,and external influencing factors such as seismic wave parameters and surrounding rock quality.Meanwhile,the effectiveness of the tunnel with the LSED structure has been quantitatively demonstrated in terms of seismic fragility curves.展开更多
To improve design accuracy and reliability of structures,this study solves the uncertain natural frequencies with consideration for geometric nonlinearity and structural uncertainty.Frequencies of the laminated plate ...To improve design accuracy and reliability of structures,this study solves the uncertain natural frequencies with consideration for geometric nonlinearity and structural uncertainty.Frequencies of the laminated plate with all four edges clamped(CCCC)are derived based on Navier's method and Galerkin's method.The novelty of the current work is that the number of unknowns in the displacement field model of a CCCC plate with free midsurface(CCCC-2 plate)is only three compared with four or five in cases of other exposed methods.The present analytical method is proved to be accurate and reliable by comparing linear natural frequencies and nonlinear natural frequencies with other models available in the open literature.Furthermore,a novel method for analyzing effects of mean values and tolerance zones of uncertain structural parameters on random frequencies is proposed based on a self-developed Multiscale Feature Extraction and Fusion Network(MFEFN)system.Compared with a direct Monte Carlo Simulation(MCS),the MFEFNbased procedure significantly reduces the calculation burden with a guarantee of accuracy.Our research provides a method to calculate nonlinear natural frequencies under two boundary conditions and presentes a surrogate model to predict frequencies for accuracy analysis and optimization design.展开更多
The development of geological lamination in shale reservoirs influences fracture propagation during hydraulic stimulation,and the fracture generation mechanism as it propagates through the laminated interface is close...The development of geological lamination in shale reservoirs influences fracture propagation during hydraulic stimulation,and the fracture generation mechanism as it propagates through the laminated interface is closely related to fracturing effects.In this paper,the laminated shale was selected to conduct three-point bending experiments using digital image correlation(DIC)and acoustic emission(AE)techniques,which revealed that the propagation path of cross-layer fractures exhibits dislocation features.The cohesive fracture mechanism of cross-layer fractures is investigated from the viewpoint of the fracture process zone(FPZ),which displays the characteristics of intermittence and dislocation during fracture development.A computational criterion for predicting the dislocation of cross-layer fracture at the interface is proposed,which shows that the maximum dislocation range does not exceed 72%of the FPZ length.Considering the mechanical differences between adjacent layers of laminated shale,the cohesive zone model of cross-layer fracture is discussed,from which the constitutive relationship and fracture energy during FPZ development are characterized,and the discontinuous nature of the constitutive relationship is found.This study improves the understanding of the geometry and cohesive fracture mechanism of the cross-layer fracture and provides valuable insights for field fracturing in shale reservoirs.展开更多
1060/7050 Al/Al laminated metal composites(LMCs)with heterogeneous lamellar structures were prepared by accumulative roll bonding(ARB),cold rolling and subsequent annealing treatment.The strengthening mechanism was in...1060/7050 Al/Al laminated metal composites(LMCs)with heterogeneous lamellar structures were prepared by accumulative roll bonding(ARB),cold rolling and subsequent annealing treatment.The strengthening mechanism was investigated by microstructural characterization,mechanical property tests and in-situ fracture morphology observations.The results show that microstructural differences between the constituent layers are present in the Al/Al LMCs after various numbers of ARB cycles.Compared with rolled 2560-layered Al/Al LMCs with 37.5%and 50.0%rolling reductions,those with 62.5%rolling reductions allow for more effective improvements in the mechanical properties after annealing treatment due to their relatively high mechanical incompatibility across the interface.During tensile deformation,with the increased magnitude of incompatibility in the 2560-layered Al/Al LMC with a heterogeneous lamellar structure,the densities of the geometrically necessary dislocations(GNDs)increase to accommodate the relatively large strain gradient,resulting in considerable back stress strengthening and improved mechanical properties.展开更多
Regarding laminated structures,an electromechanically coupled Finite Element(FE)model based on Layerwise Third-Order Shear Deformation(LW-TOSD)theory is proposed for sta-tic and dynamic analysis.LW-TOSD ensures the co...Regarding laminated structures,an electromechanically coupled Finite Element(FE)model based on Layerwise Third-Order Shear Deformation(LW-TOSD)theory is proposed for sta-tic and dynamic analysis.LW-TOSD ensures the continuity of in-plane displacements and trans-verse shear stresses.The current LW-TOSD can be applied to arbitrary multi-layer laminated structures with only seven Degrees of Freedom(DOFs)for each element node and eliminates the use of the shear correction factors.Moreover,a shear penalty stiffness matrix is constructed to sat-isfy artificial constraints to optimize the structural shear strain.A dynamic finite element model is obtained based on LW-TOSD using the Hamilton's principle.First,the accuracy of the current model is validated by comparing with literature and ABAQUS results.Then,this study carries out numerical investigations of piezolaminated structures for different width-to-thickness ratios,length-to-width ratios,penalty stiffness matrix,boundary conditions,electric fields and dynamics.展开更多
High spatiotemporal resolution brain electrical signals are critical for basic neuroscience research and high-precision focus diagnostic localization,as the spatial scale of some pathologic signals is at the submillim...High spatiotemporal resolution brain electrical signals are critical for basic neuroscience research and high-precision focus diagnostic localization,as the spatial scale of some pathologic signals is at the submillimeter or micrometer level.This entails connecting hundreds or thousands of electrode wires on a limited surface.This study reported a class of flexible,ultrathin,highdensity electrocorticogram(ECoG)electrode arrays.The challenge of a large number of wiring arrangements was overcome by a laminated structure design and processing technology improvement.The flexible,ultrathin,high-density ECoG electrode array was conformably attached to the cortex for reliable,high spatial resolution electrophysiologic recordings.The minimum spacing between electrodes was 15μm,comparable to the diameter of a single neuron.Eight hundred electrodes were prepared with an electrode density of 4444 mm^(-2).In focal epilepsy surgery,the flexible,high-density,laminated ECoG electrode array with 36 electrodes was applied to collect epileptic spike waves inrabbits,improving the positioning accuracy of epilepsy lesions from the centimeter to the submillimeter level.The flexible,high-density,laminated ECoG electrode array has potential clinical applications in intractable epilepsy and other neurologic diseases requiring high-precision electroencephalogram acquisition.展开更多
The snap-through behaviors and nonlinear vibrations are investigated for a bistable composite laminated cantilever shell subjected to transversal foundation excitation based on experimental and theoretical approaches....The snap-through behaviors and nonlinear vibrations are investigated for a bistable composite laminated cantilever shell subjected to transversal foundation excitation based on experimental and theoretical approaches.An improved experimental specimen is designed in order to satisfy the cantilever support boundary condition,which is composed of an asymmetric region and a symmetric region.The symmetric region of the experimental specimen is entirely clamped,which is rigidly connected to an electromagnetic shaker,while the asymmetric region remains free of constraint.Different motion paths are realized for the bistable cantilever shell by changing the input signal levels of the electromagnetic shaker,and the displacement responses of the shell are collected by the laser displacement sensors.The numerical simulation is conducted based on the established theoretical model of the bistable composite laminated cantilever shell,and an off-axis three-dimensional dynamic snap-through domain is obtained.The numerical solutions are in good agreement with the experimental results.The nonlinear stiffness characteristics,dynamic snap-through domain,and chaos and bifurcation behaviors of the shell are quantitatively analyzed.Due to the asymmetry of the boundary condition and the shell,the upper stable-state of the shell exhibits an obvious soft spring stiffness characteristic,and the lower stable-state shows a linear stiffness characteristic of the shell.展开更多
The dynamic responses and generated voltage in a curved sandwich beam with glass reinforced laminate(GRL)layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact(LVI)are investigate...The dynamic responses and generated voltage in a curved sandwich beam with glass reinforced laminate(GRL)layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact(LVI)are investigated.The current study aims to carry out a dynamic analysis on the sandwich beam when the impactor hits the top face sheet with an initial velocity.For the layer analysis,the high-order shear deformation theory(HSDT)and Frostig's second model for the displacement fields of the core layer are used.The classical non-adhesive elastic contact theory and Hunter's principle are used to calculate the dynamic responses in terms of time.In order to validate the analytical method,the outcomes of the current investigation are compared with those gained by the experimental tests carried out by other researchers for a rectangular composite plate subject to the LVI.Finite element(FE)simulations are conducted by means of the ABAQUS software.The effects of the parameters such as foam modulus,layer material,fiber angle,impactor mass,and its velocity on the generated voltage are reviewed.展开更多
Poly(p-phenylene-2,6-benzobisoxazole)(PBO)fiber and polytetrafluoroethylene(PTFE)resin have been widely acknowledged as excellent wave-transparent materials for future high-frequency applications due to their exceptio...Poly(p-phenylene-2,6-benzobisoxazole)(PBO)fiber and polytetrafluoroethylene(PTFE)resin have been widely acknowledged as excellent wave-transparent materials for future high-frequency applications due to their exceptional dielectric properties.However,the weak interfacial bonding between these two materials hampers their full potential.In this study,we successfully addressed this limitation by enhancing the surface roughness of PBO fibers and introducing active sites through the insitu grafting of silica nanowires.The added silica acted as an interfacial anchor on the PBO fiber surface,significantly improving the bonding force between PBO and PTFE.PBO/PTFE wave-transparent laminated composites were fabricated using hot compression molding.The results demonstrate that the PBO(treated with insitu grown silica)/PTFE laminated composites exhibit superior interlaminar shear strength(ILSS),flexural strength,flexural modulus,and tensile modulus compared to the pristine PBO/PTFE laminated composites.Specifically,these properties are found to be 58.6%,32.9%,138.1%,and 25.35%higher,respectively.Additionally,these composites demonstrate low dielectric constant and dielectric loss.Most notably,they achieve a wave transmittance of 91.45%at 10 GHz,indicating significant potential for wide-range applications in next-generation advanced military weapons,such as“lightweight/high-strength/wavetransparent”electromagnetic window materials,as well as civilian communication base stations.展开更多
The development of new design strategies to create innovative structural materials,refine existing ones,and achieves compatible combinations of strength and plasticity remains a worldwide goal.Promising alloys,such as...The development of new design strategies to create innovative structural materials,refine existing ones,and achieves compatible combinations of strength and plasticity remains a worldwide goal.Promising alloys,such as shape memory alloys(SMAs),bulk metallic glasses(BMGs),high entropy alloys(HEAs),and heterogeneous pure metals such as Cu,have excellent mechanical responses,but they still fall short of meeting all the requirements of structural materials due to specific flaws,such as lack of tensile de-formation for BMGs and low yielding strength for HEAs.To address these shortcomings,proposals such as integrating glassy matrices and crystallized alloys,such as HEAs/SMAs,have been suggested.However,these solutions have unresolved issues,such as the challenging control of B2 phase formation in BMG composites.Recently,glass-crystal(A/C)laminated alloys with alternating layers have been reported to exhibit improved mechanical properties and activated work-hardening behaviors,but they still face press-ing issues such as bonding interfaces and unknown deformation mechanisms.This review focuses on design routes such as the selection of alloy components and processing techniques,exploration of micro-structural evolution and deformation modes with an increase in strain,and future solutions to address pressing and unsolved issues.These prominent advantages include diversified deformation mechanisms,such as deformation twinning,martensitic phase transformation,and precipitation hardening,as well as tuned interactive reactions of shear bands(SBs)near the A/C interfaces.Thus,this review provides a promising pathway to design and develop structural materials in the materials field community.展开更多
基金supports for this research were provided by the National Natural Science Foundation of China(No.12272301,12002278,U1906233)the Guangdong Basic and Applied Basic Research Foundation,China(Nos.2023A1515011970,2024A1515010256)+1 种基金the Dalian City Supports Innovation and Entrepreneurship Projects for High-Level Talents,China(2021RD16)the Key R&D Project of CSCEC,China(No.CSCEC-2020-Z-4).
文摘Fiber-reinforced composites are an ideal material for the lightweight design of aerospace structures. Especially in recent years, with the rapid development of composite additive manufacturing technology, the design optimization of variable stiffness of fiber-reinforced composite laminates has attracted widespread attention from scholars and industry. In these aerospace composite structures, numerous cutout panels and shells serve as access points for maintaining electrical, fuel, and hydraulic systems. The traditional fiber-reinforced composite laminate subtractive drilling manufacturing inevitably faces the problems of interlayer delamination, fiber fracture, and burr of the laminate. Continuous fiber additive manufacturing technology offers the potential for integrated design optimization and manufacturing with high structural performance. Considering the integration of design and manufacturability in continuous fiber additive manufacturing, the paper proposes linear and nonlinear filtering strategies based on the Normal Distribution Fiber Optimization (NDFO) material interpolation scheme to overcome the challenge of discrete fiber optimization results, which are difficult to apply directly to continuous fiber additive manufacturing. With minimizing structural compliance as the objective function, the proposed approach provides a strategy to achieve continuity of discrete fiber paths in the variable stiffness design optimization of composite laminates with regular and irregular holes. In the variable stiffness design optimization model, the number of candidate fiber laying angles in the NDFO material interpolation scheme is considered as design variable. The sensitivity information of structural compliance with respect to the number of candidate fiber laying angles is obtained using the analytical sensitivity analysis method. Based on the proposed variable stiffness design optimization method for complex perforated composite laminates, the numerical examples consider the variable stiffness design optimization of typical non-perforated and perforated composite laminates with circular, square, and irregular holes, and systematically discuss the number of candidate discrete fiber laying angles, discrete fiber continuous filtering strategies, and filter radius on structural compliance, continuity, and manufacturability. The optimized discrete fiber angles of variable stiffness laminates are converted into continuous fiber laying paths using a streamlined process for continuous fiber additive manufacturing. Meanwhile, the optimized non-perforated and perforated MBB beams after discrete fiber continuous treatment, are manufactured using continuous fiber co-extrusion additive manufacturing technology to verify the effectiveness of the variable stiffness fiber optimization framework proposed in this paper.
基金supported by the Ministry of Science and Technology Taiwan under Grant No.MOST 109-2628-E-009-002-MY3.
文摘This study aims to investigate the propagation of harmonic waves in nonlocal magneto-electro-elastic(MEE)laminated composites with interface stress imperfections using an analytical approach.The pseudo-Stroh formulation and nonlocal theory proposed by Eringen were adopted to derive the propagator matrix for each layer.Both the propagator and interface matrices were formulated to determine the recursive fields.Subsequently,the dispersion equation was obtained by imposing traction-free and magneto-electric circuit open boundary conditions on the top and bottom surfaces of the plate.Dispersion curves,mode shapes,and natural frequencies were calculated for sandwich plates composed of BaTiO3 and CoFe2O4.Numerical simulations revealed that both interface stress and the nonlocal effect influenced the tuning of the dispersion curve and mode shape for the given layup.The nonlocal effect caused a significant decrease in the dispersion curves,particularly in the high-frequency regions.Additionally,compared to the nonlocal effect,the interface stress exerted a greater influence on the mode shapes.The generalized analytical framework developed in this study provides an effective tool for both the theoretical analysis and practical design of MEE composite laminates.
基金financial support from the National Key Research and Development Plan(2022YFB3707700)the National Natural Science Foundation of China(11872138 and 12172074)+1 种基金the Liaoning Revitalization Talents Program(XLYC2001003)the Dalian Excellent Young Science and Technology Talent Program(2023RY025).
文摘A partial-periodic model is proposed for predicting structural properties of composite laminate structures.The partial-periodic model contains periodic boundary conditions in one direction or two directions,and free boundary condition in other directions.In the present study,partial-periodic model for composite laminate beam structures is particularly studied.Three-point bending experiments for laminate beam specimens with different laying parameters are firstly used to verify the present partial-periodic model.In addition,a detailed finite element method(FEM)model is also used to further quantitatively compare with the present partial-periodic model for composite laminate beams with different laying parameters.The results indicate that the proposed partial-periodic model is capable of providing accurate predictions in most cases.The computational time cost of the proposed partial-periodic model is much lower than that of the detailed FEM model as well.Convergence studies are also conducted for the present partial-periodic model with different model sizes and element sizes.It is suggested that the proposed partial-periodic model has the potential to be used as an accurate and time-saving tool for predicting the structural properties of composite laminate beam structures.
基金supported by the National Natural Science Foundation of China(No.12272392 and 11790292)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB22040303)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2022020).
文摘The remarkable mechanical properties exhibited by laminated structures have generated significant in-terest in the realm of additively manufactured laminated high-entropy alloys(HEAs).Despite this bur-geoning interest,the nexus between process,structure,and properties within laminated HEAs remains largely uncharted.There is a vast space for investigating the effect of the typical heterogeneous interface on the macroscopic mechanical properties.This study focuses on the influence of the characteristic het-erogeneous interface on macroscopic mechanical properties of laminated HEAs,particularly anisotropy.Using the 3D-printed Fe_(50)Mn_(30)Co_(10)Cr_(10)-CoCrNi HEA as a model,we investigate the impact of interface geometry on mechanical characteristics.Tensile tests show that the reduced interface spacing increases yield strength.This laminated HEA displays significant anisotropy in strength and ductility,depending on the loading direction relative to the interface.Electron microscopic observations suggest that finer layer spacing enhances interface and dislocation strengthening,increasing yield strength.Anisotropic behaviors are confirmed to be mediated by interface orientation,explained in terms of deformation compatibility and crack development at the interface.This research offers fundamental insights into the relationship between heterogeneous interfaces and the mechanical properties in laminated HEAs.The knowledge is vital for designing,fabricating,and optimizing laminated HEAs through additive manufacturing,advancing their engineering applications.
基金supported by the National Natural Science Foundation of China(No.52274369)the National Key Laboratory of Science and Technology on High-strength Structural Materials,China(No.623020034).
文摘Three types of Al/Al−27%Si laminated composites,each containing 22%Si,were fabricated via hot pressing and hot rolling.The microstructures,mechanical properties and thermo-physical properties of these composites were investigated.The results demonstrated that the three laminated composites exhibited similar microstructural features,characterized by well-bonded interfaces between the Al layer and the Al−27%Si alloy layer.The tensile and flexural strengths of the composites were significantly higher than those of both Al−22%Si and Al−27%Si alloys.These strengths increased gradually with decreasing the layer thickness,reaching peak values of 222.5 and 407.4 MPa,respectively.Crack deflection was observed in the cross-sections of the bending fracture surfaces,which contributed to the enhanced strength and toughness.In terms of thermo-physical properties,the thermal conductivity of the composites was lower than that of Al−22%Si and Al−27%Si alloys.The minimum reductions in thermal conductivity were 6.8%and 0.9%for the T3 laminated composite,respectively.Additionally,the coefficient of thermal expansion of the composites was improved,exhibiting varying temperature-dependent behaviors.
基金supported by the National Natural Science Foundation of China(Nos.52375394,52074246,52275390,52205429,52201146)the National Defense Basic Scientific Research Program of China(JCKY2020408B002)the Key Research and Development Program of Shanxi Province(202102050201011,202202050201014).
文摘In Ti-Al laminated composites,cracks nucleate preferentially at the Al_(3)Ti layer,but the inhibitory effect of Al_(3)Ti on crack extension is ignored.Interestingly,by combining experiment and phase-field crystal simulation,we found that the micrometer Al_(3)Ti particles in the diffusion layer play the role of crack deflection and passivation,which is attributed to the lattice distortion induced by Al_(3)Ti consumes the energy of the crack in extension.In addition,it is found that the growth process of Al_(3)Ti is divided into two stages:nucleation stage and growth stage.Compared with the growth stage,the Al_(3)Ti grains in the nucleation stage are finer in the growth layer.Finer grains show better crack deflection and avoid stress concentration.
基金the financial support from the National Natural Science Foundation of China(Nos.51875317,52222510)Key Research and Development Program of Shandong Province,China(No.2021ZLGX01)。
文摘Al/Cu laminate composite was fabricated based on hot press sintering using Cu sheet and Al powders as raw materials.The effects of sintering parameters on interfacial structure and mechanical properties were investigated.The results revealed that a uniform Al/Cu interface with excellent bonding quality was achieved.The thickness of intermetallic compounds(IMCs)reached 33.88μm after sintering at 620℃for 2 h,whereas it was only 14.88μm when sintered at 600℃for 1 h.AlCu phase was developed through the reaction between Al4Cu9 and Al2Cu with prolonging sintering time,and an amorphous oxide strip formed at AlCu/Al4Cu9 interface.Both the grain morphology and interfacial structure affected the tensile strength of Al/Cu laminate,whereas the mode of tensile fracture strongly relied on the interfacial bonding strength.The highest tensile strength of 151.1 MPa and bonding strength of 93.7 MPa were achieved after sintering at 600℃for 1 h.
基金supported by the National Natural Science Fund of China(Nos.52005153,12227801,32300666,12072005,U23A2607)the Tianjin"Project+Team"Key Training Program,China(No.XC202052)+4 种基金the Key Program of Research and Development of Hebei Province,China(Nos.202030507040009,23311812D)the Natural Science Foundation of Hebei Province,China(No.E2023202183)the Project of High-Level Team Construction Introduction of Hebei Province,China(No.244A7620D)the Research Cooperation Project of Universities Stationed in Hebei Province and Shijiazhuang City,China(No.241080114A)Hebei Province Military-Civilian Integration Science and Technology Innovation Project,China(No.SJMYF2022X15)。
文摘Fiber Metal Laminates(FMLs),as high-performance composite materials,demonstrate exceptional potential in a wide range of applications,such as aeronautical and astronautical industries.However,the traditional cured FMLs possess complex interlayer stresses and low forming limits,restricting further promotion and application of FMLs.Low-constraint FMLs exhibit a lower forming resistance and better formability due to no curing during the forming process;however,the formation mechanism and response are not clear.This paper presents the Forming Limit Diagram(FLD)of low-constraint GLARE(glass fiber reinforced aluminum laminates)based on the forming limit test,and compares it with the conventionally cured laminates to evaluate the differences in the forming limit.In addition,combined with the analysis of failure mechanism and micro-deformation mechanism of specimens,the influence of different temperatures(20–80℃)and forming states(width)on the deformation performance of laminates is further explored.The results reveal that the forming limit curve of low-constraint laminates shifts up with the increase of temperature,the forming limit initially increases with the increase of width,then followed by a gradual decrease,and the maximum principal strain of low-constraint laminates is increased by 29% at 80℃ compared to 20℃.The cured laminate has a principal strain range of 0–0.02,while the low-constraint laminates have a principal strain range of 0.03–0.14.Compared with cured laminates,low-constraint laminates possess a higher forming limit due to the improvement in deformable degree between layers by resin flow and fiber slippage,which enhances their formability.This study is expected to serve as a reference for establishing forming limit criteria and optimizing forming schemes for low-constraint laminates.
基金the National Key Research and Development Program of China(No.2018YFE0306103)the National Natural Science Foundation of China(No.52071050)+1 种基金the Science and Technology Innovation Project of Ningbo,China(No.2021Z032)the Program of China Scholarships Council(No.202106060148).
文摘The Cu/1010 steel bimetal laminated composites(BLCs)were rolled to different thicknesses to investigate the effect of rolling direction and reduction on the microstructure evolution and mechanical properties.The difference of mechanical properties between the Cu and 1010 steel causes different thickness reductions,percentage spread,and cladding ratios.The formation of strong texture induces larger strength of the rolled samples,and as the volume fraction of 1010 steel is larger in Route-A,its strength is consistently greater than that in Route-B.The obstruction of interface to crystal and dislocation slip results in the formation of interface distortion,inducing dislocation density gradient when the rolling reduction is low in Route-A.The slip planes of the Cu and 1010 steel are more prone to suffer the normal strain,while the shear strain of other crystal planes is obviously larger than the normal strain under rolling load near the interface.
文摘Plasma electrolytic oxidation(PEO)coatings were prepared on Al−Mg laminated macro composites(LMCs)using both unipolar and bipolar waveforms in an appropriate electrolyte for both aluminum and magnesium alloys.The techniques of FESEM/EDS,grazing incident beam X-ray diffraction(GIXRD),and electrochemical methods of potentiodynamic polarization and electrochemical impedance spectroscopy(EIS)were used to characterize the coatings.The results revealed that the coatings produced using the bipolar waveform exhibited lower porosity and higher thickness than those produced using the unipolar one.The corrosion performance of the specimens’cut edge was investigated using EIS after 1,8,and 12 h of immersion in a 3.5 wt.%NaCl solution.It was observed that the coating produced using the bipolar waveform demonstrated the highest corrosion resistance after 12 h of immersion,with an estimated corrosion resistance of 5.64 kΩ·cm^(2),which was approximately 3 times higher than that of the unipolar coating.Notably,no signs of galvanic corrosion were observed in the LMCs,and only minor corrosion attacks were observed on the magnesium layer in some areas.
基金supported by the National Natural Science Foundation of China(Grant No.52109132)the Shandong Provincial Natural Science Foundation(Grant No.ZR2020QE270).
文摘Longitudinal seismic performance is a critical aspect to be considered during the tunnel design process,in addition to cross-sectional considerations.The present study proposed using a laminated shear energy dissipation(LSED)structure to achieve effective longitudinal seismic design.The proposed structure consists of thin steel plates and alternately bonded layers of rubber,which can be installed around the periphery of the secondary lining.This configuration guarantees that the tunnels will exhibit optimal axial deformation capacity and robust rigid resistance to circumferential compression from the surrounding rock.To evaluate the impact of the LSED structure on the longitudinal seismic performance of the tunnel,a fine numerical model of the LSED structureetunnel liningesurrounding rock system was developed using finite element simulation.The evaluation criteria include maximum principal stress and strain energy.The seismic response of the tunnel with the LSED structure exhibited a notable reduction of over 40%in terms of seismic attenuation rate when subjected to the Trinidad seismic wave compared to the tunnel without the LSED structure.Furthermore,the aseismic mechanism of the proposed LSED structure is discussed,considering both internal factors such as the rubber shear modulus,steel plate dimensions,and number and location of structures,and external influencing factors such as seismic wave parameters and surrounding rock quality.Meanwhile,the effectiveness of the tunnel with the LSED structure has been quantitatively demonstrated in terms of seismic fragility curves.
基金the research project funded by the Fundamental Research Funds for the Central Universities(No.HIT.OCEP.2024038)the National Natural Science Foundation of China(No.52372351)the State Key Laboratory of Micro-Spacecraft Rapid Design and Intelligent Cluster,China(No.MS02240107)。
文摘To improve design accuracy and reliability of structures,this study solves the uncertain natural frequencies with consideration for geometric nonlinearity and structural uncertainty.Frequencies of the laminated plate with all four edges clamped(CCCC)are derived based on Navier's method and Galerkin's method.The novelty of the current work is that the number of unknowns in the displacement field model of a CCCC plate with free midsurface(CCCC-2 plate)is only three compared with four or five in cases of other exposed methods.The present analytical method is proved to be accurate and reliable by comparing linear natural frequencies and nonlinear natural frequencies with other models available in the open literature.Furthermore,a novel method for analyzing effects of mean values and tolerance zones of uncertain structural parameters on random frequencies is proposed based on a self-developed Multiscale Feature Extraction and Fusion Network(MFEFN)system.Compared with a direct Monte Carlo Simulation(MCS),the MFEFNbased procedure significantly reduces the calculation burden with a guarantee of accuracy.Our research provides a method to calculate nonlinear natural frequencies under two boundary conditions and presentes a surrogate model to predict frequencies for accuracy analysis and optimization design.
基金financiallysupported by the Excellent Young Fund of Sinopec Petroleum Exploration and Production Research Institute(Grant No.YK2024009)the National Natural Science Foundation of China(Grant Nos.U23B6004 and 51925405).
文摘The development of geological lamination in shale reservoirs influences fracture propagation during hydraulic stimulation,and the fracture generation mechanism as it propagates through the laminated interface is closely related to fracturing effects.In this paper,the laminated shale was selected to conduct three-point bending experiments using digital image correlation(DIC)and acoustic emission(AE)techniques,which revealed that the propagation path of cross-layer fractures exhibits dislocation features.The cohesive fracture mechanism of cross-layer fractures is investigated from the viewpoint of the fracture process zone(FPZ),which displays the characteristics of intermittence and dislocation during fracture development.A computational criterion for predicting the dislocation of cross-layer fracture at the interface is proposed,which shows that the maximum dislocation range does not exceed 72%of the FPZ length.Considering the mechanical differences between adjacent layers of laminated shale,the cohesive zone model of cross-layer fracture is discussed,from which the constitutive relationship and fracture energy during FPZ development are characterized,and the discontinuous nature of the constitutive relationship is found.This study improves the understanding of the geometry and cohesive fracture mechanism of the cross-layer fracture and provides valuable insights for field fracturing in shale reservoirs.
基金financial support from the Special Fund for Special Posts of Guizhou University,China(No.[2022]06)the Guizhou Provincial Basic Research Program(Natural Science),China(No.ZK[2023]78)+1 种基金the National Natural Science Foundation of China(No.52365020)the Open Fund Project of Key Laboratory of Advanced Manufacturing Technology,China(No.GZUAMT2022KF[04]).
文摘1060/7050 Al/Al laminated metal composites(LMCs)with heterogeneous lamellar structures were prepared by accumulative roll bonding(ARB),cold rolling and subsequent annealing treatment.The strengthening mechanism was investigated by microstructural characterization,mechanical property tests and in-situ fracture morphology observations.The results show that microstructural differences between the constituent layers are present in the Al/Al LMCs after various numbers of ARB cycles.Compared with rolled 2560-layered Al/Al LMCs with 37.5%and 50.0%rolling reductions,those with 62.5%rolling reductions allow for more effective improvements in the mechanical properties after annealing treatment due to their relatively high mechanical incompatibility across the interface.During tensile deformation,with the increased magnitude of incompatibility in the 2560-layered Al/Al LMC with a heterogeneous lamellar structure,the densities of the geometrically necessary dislocations(GNDs)increase to accommodate the relatively large strain gradient,resulting in considerable back stress strengthening and improved mechanical properties.
基金support from the National Natural Science Foundation of China (No.11972020)the Natural Science Foundation of Shanghai,China (No.21ZR1424100).
文摘Regarding laminated structures,an electromechanically coupled Finite Element(FE)model based on Layerwise Third-Order Shear Deformation(LW-TOSD)theory is proposed for sta-tic and dynamic analysis.LW-TOSD ensures the continuity of in-plane displacements and trans-verse shear stresses.The current LW-TOSD can be applied to arbitrary multi-layer laminated structures with only seven Degrees of Freedom(DOFs)for each element node and eliminates the use of the shear correction factors.Moreover,a shear penalty stiffness matrix is constructed to sat-isfy artificial constraints to optimize the structural shear strain.A dynamic finite element model is obtained based on LW-TOSD using the Hamilton's principle.First,the accuracy of the current model is validated by comparing with literature and ABAQUS results.Then,this study carries out numerical investigations of piezolaminated structures for different width-to-thickness ratios,length-to-width ratios,penalty stiffness matrix,boundary conditions,electric fields and dynamics.
基金support of the National Natural Science Foundation of China(Nos.U20A6001,12002190,11972207,and 11921002)the Fundamental Research Funds for the Central Universities,China(No.SWUKQ22029)the Chongqing Natural Science Foundation of China(No.CSTB2022NSCQ-MSX1635).
文摘High spatiotemporal resolution brain electrical signals are critical for basic neuroscience research and high-precision focus diagnostic localization,as the spatial scale of some pathologic signals is at the submillimeter or micrometer level.This entails connecting hundreds or thousands of electrode wires on a limited surface.This study reported a class of flexible,ultrathin,highdensity electrocorticogram(ECoG)electrode arrays.The challenge of a large number of wiring arrangements was overcome by a laminated structure design and processing technology improvement.The flexible,ultrathin,high-density ECoG electrode array was conformably attached to the cortex for reliable,high spatial resolution electrophysiologic recordings.The minimum spacing between electrodes was 15μm,comparable to the diameter of a single neuron.Eight hundred electrodes were prepared with an electrode density of 4444 mm^(-2).In focal epilepsy surgery,the flexible,high-density,laminated ECoG electrode array with 36 electrodes was applied to collect epileptic spike waves inrabbits,improving the positioning accuracy of epilepsy lesions from the centimeter to the submillimeter level.The flexible,high-density,laminated ECoG electrode array has potential clinical applications in intractable epilepsy and other neurologic diseases requiring high-precision electroencephalogram acquisition.
基金Project supported by the National Natural Science Foundation of China(Nos.11832002 and 12072201)。
文摘The snap-through behaviors and nonlinear vibrations are investigated for a bistable composite laminated cantilever shell subjected to transversal foundation excitation based on experimental and theoretical approaches.An improved experimental specimen is designed in order to satisfy the cantilever support boundary condition,which is composed of an asymmetric region and a symmetric region.The symmetric region of the experimental specimen is entirely clamped,which is rigidly connected to an electromagnetic shaker,while the asymmetric region remains free of constraint.Different motion paths are realized for the bistable cantilever shell by changing the input signal levels of the electromagnetic shaker,and the displacement responses of the shell are collected by the laser displacement sensors.The numerical simulation is conducted based on the established theoretical model of the bistable composite laminated cantilever shell,and an off-axis three-dimensional dynamic snap-through domain is obtained.The numerical solutions are in good agreement with the experimental results.The nonlinear stiffness characteristics,dynamic snap-through domain,and chaos and bifurcation behaviors of the shell are quantitatively analyzed.Due to the asymmetry of the boundary condition and the shell,the upper stable-state of the shell exhibits an obvious soft spring stiffness characteristic,and the lower stable-state shows a linear stiffness characteristic of the shell.
文摘The dynamic responses and generated voltage in a curved sandwich beam with glass reinforced laminate(GRL)layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact(LVI)are investigated.The current study aims to carry out a dynamic analysis on the sandwich beam when the impactor hits the top face sheet with an initial velocity.For the layer analysis,the high-order shear deformation theory(HSDT)and Frostig's second model for the displacement fields of the core layer are used.The classical non-adhesive elastic contact theory and Hunter's principle are used to calculate the dynamic responses in terms of time.In order to validate the analytical method,the outcomes of the current investigation are compared with those gained by the experimental tests carried out by other researchers for a rectangular composite plate subject to the LVI.Finite element(FE)simulations are conducted by means of the ABAQUS software.The effects of the parameters such as foam modulus,layer material,fiber angle,impactor mass,and its velocity on the generated voltage are reviewed.
基金supported by the National Natural Science Foundation of China(No.U21A2094)CASHIPS Director’s Fund(Nos.YZJJZX202015,YZJJ202304-CX,YZJJ2023QN36)+1 种基金Anhui Province Postdoctoral Researcher Research Project(No.E24F0D27)Central Government Guiding Local Government Science and Technology Development Special Fund Project(No.2022ZB09002).
文摘Poly(p-phenylene-2,6-benzobisoxazole)(PBO)fiber and polytetrafluoroethylene(PTFE)resin have been widely acknowledged as excellent wave-transparent materials for future high-frequency applications due to their exceptional dielectric properties.However,the weak interfacial bonding between these two materials hampers their full potential.In this study,we successfully addressed this limitation by enhancing the surface roughness of PBO fibers and introducing active sites through the insitu grafting of silica nanowires.The added silica acted as an interfacial anchor on the PBO fiber surface,significantly improving the bonding force between PBO and PTFE.PBO/PTFE wave-transparent laminated composites were fabricated using hot compression molding.The results demonstrate that the PBO(treated with insitu grown silica)/PTFE laminated composites exhibit superior interlaminar shear strength(ILSS),flexural strength,flexural modulus,and tensile modulus compared to the pristine PBO/PTFE laminated composites.Specifically,these properties are found to be 58.6%,32.9%,138.1%,and 25.35%higher,respectively.Additionally,these composites demonstrate low dielectric constant and dielectric loss.Most notably,they achieve a wave transmittance of 91.45%at 10 GHz,indicating significant potential for wide-range applications in next-generation advanced military weapons,such as“lightweight/high-strength/wavetransparent”electromagnetic window materials,as well as civilian communication base stations.
基金supported by the China National Natural Science Foundation(No.52071217)the Guangdong Key Laboratory of Electromagnetic Control and Intelligent Robots.
文摘The development of new design strategies to create innovative structural materials,refine existing ones,and achieves compatible combinations of strength and plasticity remains a worldwide goal.Promising alloys,such as shape memory alloys(SMAs),bulk metallic glasses(BMGs),high entropy alloys(HEAs),and heterogeneous pure metals such as Cu,have excellent mechanical responses,but they still fall short of meeting all the requirements of structural materials due to specific flaws,such as lack of tensile de-formation for BMGs and low yielding strength for HEAs.To address these shortcomings,proposals such as integrating glassy matrices and crystallized alloys,such as HEAs/SMAs,have been suggested.However,these solutions have unresolved issues,such as the challenging control of B2 phase formation in BMG composites.Recently,glass-crystal(A/C)laminated alloys with alternating layers have been reported to exhibit improved mechanical properties and activated work-hardening behaviors,but they still face press-ing issues such as bonding interfaces and unknown deformation mechanisms.This review focuses on design routes such as the selection of alloy components and processing techniques,exploration of micro-structural evolution and deformation modes with an increase in strain,and future solutions to address pressing and unsolved issues.These prominent advantages include diversified deformation mechanisms,such as deformation twinning,martensitic phase transformation,and precipitation hardening,as well as tuned interactive reactions of shear bands(SBs)near the A/C interfaces.Thus,this review provides a promising pathway to design and develop structural materials in the materials field community.
