A shaking table test was performed to investigate the different responses of piles with and without cement-soil reinforcement,considering both inertial and kinematic interactions.A comparison of the dynamic shear stre...A shaking table test was performed to investigate the different responses of piles with and without cement-soil reinforcement,considering both inertial and kinematic interactions.A comparison of the dynamic shear stress−strain hysteresis curves of soil profiles on the pile side with and without cement-soil reinforced piles indicates that cement-soil reinforced piles not only bear more tremendous shear stress but also have smaller strains under the action of cyclic shear stress.Furthermore,the cement-soil on the pile side not only shares part of the shear stress and modifies the bending moment distribution but also significantly enhances the resistance of the pile-side soil,reducing the lateral displacement of the superstructure.Cement-soil reinforcement reduced shear strains,inhibited sand liquefaction,and reduced superstructure displacements by 27%−47%(instantaneous)and 40%−65%(permanent).The proportion of horizontal load sharing between cement-soil reinforcement and saturated sand is considered,along with the change pattern of the subgrade reaction after sand liquefaction.An equivalent subgrade reaction calculation method is proposed,which accounts for the horizontal load-sharing ratios of soils with two different strengths.The test results indicate that the pile stress and displacement,estimated using the equivalent subgrade reaction,are in good agreement with the observed results.展开更多
The high-quality assembly of Large Aircraft Components(LACs)is essential in modern aviation manufacturing.Numerical control locators are employed for the posture adjustment of LAC,yet the system's multi-input mult...The high-quality assembly of Large Aircraft Components(LACs)is essential in modern aviation manufacturing.Numerical control locators are employed for the posture adjustment of LAC,yet the system's multi-input multi-output,nonlinearity,and strong coupling presents significant challenges.The substantial internal force generated during the adjustment process can potentially damage the LAC and degrade the assembly quality.Hence,a workspace-based hybrid force position control scheme was developed to achieve high quality assembly with high-precision and lower internal force.Firstly,an offline workspace analysis with inherent geometric characteristics to form time-varying posture error constraint.Then,the posture error is integrated into the online position axis control to ensure tracking the ideal posture,while the force control axis compensates for posture deviation by minimizing internal force,thereby achieving high precision and low internal force.Finally,the effectiveness was demonstrated through experiments.The root mean square errors of orientation and position are 104 rad and 0.1 mm,respectively.A reduction in internal force can range from 10.96%to 57.4%compared to the traditional method.Key points'max position error is decreased from 0.32 mm to 0.18 mm,satisfying the 0.5 mm tolerance.Therefore,the proposed method will help promote the development of high-performance manufacturing.展开更多
Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pell...Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pellets.Addressing the gap in the application of organically-intercalated modified bentonite in the pelletizing field,this study introduces an innovative modification process for bentonite that employs the synergistic effect of mechanical force and dimethyl sulfoxide to enhance the intercalation of organic compounds within bentonite,thus significantly enhancing its binding performance.The colloid value and swell capacity of modified bentonite(98.5 m L/3g and 55.0 m L/g)were much higher than the original bentonite(90.5 m L/3g and 17.5 m L/g).With the decrease of bentonite dosage from1.5wt%to 1.0wt%,the drop number of green pellets from a height of 0.5 m and the compressive strengths of roasted pellets using the modified bentonite(6.0 times and 2916 N per pellet)were significantly higher than those of the original bentonite(4.0 times and 2739 N per pellet).This study provides a comprehensive analysis of the intercalation modification mechanism of bentonite,offering crucial technical insights for the development of high-performance modified bentonite as iron ore pellet binders.展开更多
In the context of the coordinated pursuit of"carbon peak and neutrality"objectives,alongside the strategy to establish a robust agricultural nation,the economic and social development of rural areas is under...In the context of the coordinated pursuit of"carbon peak and neutrality"objectives,alongside the strategy to establish a robust agricultural nation,the economic and social development of rural areas is undergoing a profound paradigm shift.The traditional rural division of labor pattern,which depends on tangible factors such as land,labor,and capital,has increasingly encountered developmental challenges characterized by diminishing marginal returns and a detrimental cycle of internal competition.The new quality productive force,centered on data,algorithms,green technologies,bioengineering,and clean energy,offers a potential pathway for the rural division of labor system to overcome the"low-level equilibrium".This force is characterized by attributes such as non-exclusivity,replicability,network collaboration,and ecological compatibility.This paper develops a three-dimensional collaborative analytical framework encompassing"technology,institution,and culture".It systematically elucidates the internal logic by which new quality productive forces drive the transformation of the rural division of labor from"quantitative factor matching"to"qualitative structural reorganization"through three principal mechanisms:technology embedding,institutional reconstruction,and cultural coupling.Furthermore,the study proposes corresponding policy recommendations,thereby offering theoretical insights to support the modernization of China s agriculture and rural areas,as well as the development of a strong agricultural country.展开更多
Accurate mechanical modeling is essential for robotic belt grinding(RBG), a process characterized by compliant contact mechanisms that make force prediction particularly challenging. However, existing mechanical model...Accurate mechanical modeling is essential for robotic belt grinding(RBG), a process characterized by compliant contact mechanisms that make force prediction particularly challenging. However, existing mechanical models predominantly focus on macroscale compliance while neglecting grain-scale compliant motion. Moreover, abrasive grains are typically idealized as regular shapes, overlooking the inherent stochasticity of real grain geometries. This study proposes a shapeequivalence method for modeling stochastic abrasive grains and develops a multiscale compliant force model for RBG. Specifically, an individual grain is represented as a polygonal pyramid with stochastic edges that is mathematically equivalent to a cone;this method unifies the treatment of grain geometries and streamlines the modeling process. The mathematical equivalence relationship for random grain shapes is further derived based on a grain-compliant contact model. By integrating grain geometric characteristics and progressive grain wear, an analytical mechanical model that captures both the static contact force and dynamic grinding force is established, thereby describing the transition from grain-workpiece compliant interaction to belt-workpiece elastic contact. Grinding experiments were conducted using abrasive belts with different grain shape distributions to validate the model. The results demonstrated reliable predictions of the tangential grinding force and its component characteristics. Additional analyses were performed to reveal how the tangential grinding force varies with wear time and grinding parameters.展开更多
Manned aerial vehicle-unmanned aerial vehicle(MAV-UAV)combat organization is a MAV-UAV combat collective formed from the perspective of organization design theory and methodology,and the generation of force formation ...Manned aerial vehicle-unmanned aerial vehicle(MAV-UAV)combat organization is a MAV-UAV combat collective formed from the perspective of organization design theory and methodology,and the generation of force formation plan is a key step in the organizational planning.Based on the description of the problem and the definition of organizational elements,the matching model of platform-target attack wave is constructed to minimize the redundancy of command and decision-making capability,resource capability and the number of platforms used.Based on the non-dominated sorting genetic algorithmⅢ(NSGA-Ⅲ)framework,which includes encoding/decoding method and constraint handling method,the generation model of organizational force formation plan is solved,and the effectiveness and superiority of the algorithm are verified by simulation experiments.展开更多
Sandwich functionally graded(FG)auxetic beams are extensively utilized in aerospace,automotive,and biomedical industries due to their excellent strength-toweight ratio,impact resistance,and tunable mechanical properti...Sandwich functionally graded(FG)auxetic beams are extensively utilized in aerospace,automotive,and biomedical industries due to their excellent strength-toweight ratio,impact resistance,and tunable mechanical properties.The integration of FG materials with auxetic structures enhances their adaptability in advanced engineering applications.However,understanding their dynamic behavior under external excitations is essential for optimal design and structural reliability.Nonlinear interactions in such structures pose significant challenges in vibration analysis,necessitating robust analytical methods.This study presents a closed-form solution for the nonlinear forced vibration analysis of sandwich FG auxetic beams,offering an accurate and efficient method for predicting their dynamic response.The beam consists of two FG face sheets with material properties varying through the thickness and a re-entrant honeycomb auxetic core with an adjustable Poisson's ratio.The governing nonlinear equations of motion are derived using the first-order shear deformation theory(FSDT),the modified Gibson model,and the von Kármán relations,formulated through Hamilton's principle.A closed-form solution is obtained via the Galerkin method and multiple-scale technique.The results demonstrate that FG layers enable control of the overweight and dynamic response amplitude,with positive power law indexes reducing weight.Comparisons with finite element results confirm the accuracy of the proposed formulation.展开更多
Nowadays,force sensors play an important role in industrial production,electronic information,medical health,and many other fields.Two-dimensional material-based filed effect transistor(2D-FET)sensors are competitive ...Nowadays,force sensors play an important role in industrial production,electronic information,medical health,and many other fields.Two-dimensional material-based filed effect transistor(2D-FET)sensors are competitive with nano-level size,lower power consumption,and accurate response.However,few of them has the capability of impulse detection which is a path function,expressing the cumulative effect of the force on the particle over a period of time.Herein we fabricated the flexible polymethyl methacrylate(PMMA)gate dielectric MoS_(2)-FET for force and impulse sensor application.We systematically investigated the responses of the sensor to constant force and varying forces,and achieved the conversion factors of the drain current signals(I_(ds))to the detected impulse(I).The applied force was detected and recorded by I_(ds)with a low power consumption of~30 nW.The sensitivity of the device can reach~8000%and the 4×1 sensor array is able to detect and locate the normal force applied on it.Moreover,there was almost no performance loss for the device as left in the air for two months.展开更多
Astronomical extreme events or phenomena include black holes as well as nebulae systems that resemble the Milky Way. Meteorological extreme events or phenomena include tornadoes and tropical cyclones. The new high ene...Astronomical extreme events or phenomena include black holes as well as nebulae systems that resemble the Milky Way. Meteorological extreme events or phenomena include tornadoes and tropical cyclones. The new high energy state of matter expanding outwards by spin jets from the two poles of an astronomical black hole, the new high energy state of matter in a funnel-shaped vortex showed a meteorological tornado expanding downwards from a rotated disk of cumulonimbus clouds, the new high energy state of matter in a tropical cyclone and the new high energy state of a nebulae system converging celestial materials are phenomena across disciplines and multiple time-space scales that have not yet been physically explained. In this paper, the theory of orthogonal collision in the rotational contraction continuum is used to unify the understanding of diverse extreme events or phenomena through a single dynamical mechanism, offering insights into natural processes across disciplines. In the field of astronomy, the orthogonal collision of two-beam rotating and contracting particles or stars associated with centripetal forces forms a new high-energy state of matter at the collision point and the new high-energy particles have expanding forces outward to both sides of the collision plane. In the field of meteorology, the orthogonal collision of multiple horizontally rotating and contracting airflows associated with centripetal forces forms a new high energy state of matter at the collision point as well as an updraft force and a downdraft force vertically. The updraft force and downdraft force formed by the collision of anomalous wet airflows in the lower atmosphere can well indicate tornado, thunderstorm and extreme precipitation. The orthogonal collision theory can be applied to explain new states of matter in disciplines from the astronomical scale to the meteorological scale and the Planck scale.展开更多
Soft robots,as a modern gateway to unlocking the mysteries of underwater realms,present new complexities.Modeling their behavior when in contact with external forces,whether point-based or distributed,is a primary cha...Soft robots,as a modern gateway to unlocking the mysteries of underwater realms,present new complexities.Modeling their behavior when in contact with external forces,whether point-based or distributed,is a primary challenge due to the nature of soft bodies.To obtain a holistic view of the system’s behavior determining the governing dynamics is deemed necessary.This paper proposes a new technique to simulate the dynamic lateral undulation of a soft robotic fish with a cable-driven soft tail.By integrating the rigid finite element method with rigid-body robotics,the model represents the undulation of a finite number of rigid elements connected through a set of torsional spring and damper.Instead of directly modeling external forces,we substitute equivalent joint torques into the system dynamics,allowing us to consider external effects without complicating the model.The resulting model yields valuable insights into the system’s behavior,including propulsive and lateral forces.A comparison with experimental results shows strong agreement,with a tip amplitude error of 10% at 0.8 Hz,5.25% at 1.6 Hz and 2.54%at 2.2 Hz flapping frequency.These findings illuminate the influence of lateral undulation on the overall dynamics,paving the way for fully autonomous robotic fish.展开更多
With the intensification of lunar exploration,the failure risk caused by the adsorption of lunar dust on the spacecraft surface cannot be ignored.Therefore,three types of typical spatial solid lubrication films,namely...With the intensification of lunar exploration,the failure risk caused by the adsorption of lunar dust on the spacecraft surface cannot be ignored.Therefore,three types of typical spatial solid lubrication films,namely polytetrafluoroethylene(PTFE),amorphous carbon(a-C)and molybdenum disulfide(MoS2),were prepared as test samples.Firstly,the surface free energy parameters of the material were measured using a contact Angle measuring instrument.At the same time,atomic force microscopy(AFM)was used to quantify the adhesion of the film samples based on the lunar dust micro-adsorption model.In order to investigate the influence of the test environment,the environmental pressure was adjusted to normal pressure environment and high vacuum environment with a vacuum degree of 10−6 Pa for testing.The results indicate a positive correlation between surface energy and adhesion.As surface energy increases,molecules tend to move closer,forming a stronger attraction and thus enhancing surface adhesion.In addition,AFM was used to measure the adhesion force under atmospheric pressure and vacuum conditions,revealing that parameters measured in atmospheric environment were generally higher than those measured in vacuum,which effectively verified the existence of capillary force in the microscopic adsorption model and its influence on the adhesion effect.Through the test comparison of three groups of typical solid lubricating films,it is found that MoS2 has a lower adhesion effect than the other two groups of films,which can effectively reduce the adhesion phenomenon of lunar dust on the surface of the material,and provide suitable materials for future lunar exploration and manned lunar missions.展开更多
Human skin exhibits a remarkable capability to perceive contact forces and environmental temperatures,providing complex information that is essential for its subtle control.Despite recent advancements in soft tactile ...Human skin exhibits a remarkable capability to perceive contact forces and environmental temperatures,providing complex information that is essential for its subtle control.Despite recent advancements in soft tactile sensors,accurately decoupling signals—specifically separating forces from directional orientation and temperature—remains a challenge thus resulting in failure to meet the advanced application requirements of robots.This study proposes,F3T,a multilayer soft sensor unit designed to achieve isolated measurements and mathematical decoupling of normal pressure,omnidirectional tangential forces,and temperature.We developed a circular coaxial magnetic film featuring a floating mount multilayer capacitor that facilitated the physical decoupling of normal and tangential forces in all directions.Additionally,we incorporated an ion gel-based temperature-sensing film into the tactile sensor.The proposed sensor was resilient to external pressures and deformations,and could measure temperature and significantly eliminate capacitor errors induced by environmental temperature changes.In conclusion,our novel design allowed for the decoupled measurement of multiple signals,laying the foundation for advancements in high-level robotic motion control,autonomous decision-making,and task planning.展开更多
The purpose of this article is to provide,from the perspective of deformable solid mechanics,a correct justification for the expressions of all forces acting on the surface of a ferromagnetic material in a magnetic fi...The purpose of this article is to provide,from the perspective of deformable solid mechanics,a correct justification for the expressions of all forces acting on the surface of a ferromagnetic material in a magnetic field,initiated only by this field.It is shown that the moment of force applied to any closed body surface S,corresponding to the asymmetric part TAof the stress tensor T(denoted as the force pA),balances the mass magnetic moment Lmagacting in the volume V bounded by the surface S.The emergence of the asymmetric part TAof the stress tensor arises as a consequence of a special case within the moment theory of elasticity,the use of which is necessary for accurately describing the behavior of a ferromagnetic material in a magnetic field.The force pa acts in a plane tangential to the surface S at any point,while,in addition to this force,the normal force pn also acts on the body surface.It is shown in the article that the latter force arises as a result of a jump in the normal component of the magnetic field strength appearing at the body surface,and its expression is defined by the mass' s(ponderomotive) magnetic forces Fmag.Usually,this force is introduced based on the Maxwell stress tensor,which is used in the classical electromagnetism to represent the interaction between electromagnetic forces and mechanical momentum.However,as we believe and justify this in the article,such an approach is unacceptable in deformable solid mechanics.展开更多
Recently,charged solitons have been found in a two-dimensional CoCl_(2)/HOPG system,whose microscopic nature remains to be elusive.In this work,we investigate the charged solitons in monolayer CoCl_(2) using scanning ...Recently,charged solitons have been found in a two-dimensional CoCl_(2)/HOPG system,whose microscopic nature remains to be elusive.In this work,we investigate the charged solitons in monolayer CoCl_(2) using scanning tunneling microscopy(STM)and atomic force microscopy(AFM).Moreover,we study the electrical properties of the charged solitons at zero electric field by measuring local contact potential difference(LCPD)via Kelvin probe force microscopy(KPFM)using the Δf(V)method.The compensation voltage corresponding to the vertex of the parabola is obtained by fitting the quadratic relationship between Δf and sample bias.The results show that,without an external electric field,the solitons behave as negatively charged entities.Meanwhile,the LCPD mapping characterizes the spatial distribution of the potential at the charged solitons,which agrees well with those obtained from STM band bending measurements.展开更多
This study presents a closed-form solution for central stress,a semi-analytical model,and a modified anisotropic semi-analytical model to efficiently calculate the forcefrequency coefficients(FFCs)of square quartz cry...This study presents a closed-form solution for central stress,a semi-analytical model,and a modified anisotropic semi-analytical model to efficiently calculate the forcefrequency coefficients(FFCs)of square quartz crystal resonators(QCRs)with different side lengths and azimuth angles under eccentrically concentrated and distributed loads.The semi-analytical model is validated by comparisons between the experimental results and the nonlinear finite element method(FEM)simulation results.Based on the semi-analytical model for the FFC and nonlinear FEM simulations,the FFC variations of square QCRs under external loads and the related mechanisms are investigated.Among the initial stresses caused by external loads,the central stress parallel to the xcrystallographic axis is the primary factor influencing the FFC of quartz.Our findings can provide practical tools for calculating the FFC,and help the design and development of square quartz force sensors.展开更多
The frequent or occasional impact loads pose serious threats to the service safety of conventional concrete structures in tunnel.In this paper,a novel three-dimensional mesoscopic model of steel fiber reinforced concr...The frequent or occasional impact loads pose serious threats to the service safety of conventional concrete structures in tunnel.In this paper,a novel three-dimensional mesoscopic model of steel fiber reinforced concrete(SFRC)is constructed by discrete element method.The model encompasses the concrete matrix,aggregate,interfacial transition zone and steel fibers,taking into account the random shape of the coarse aggregate and the stochastic distribution of steel fibers.It captures microscopic-level interactions among the coarse aggregate,steel fibers,and matrix.Subsequently,a comprehensive procedure is formulated to calibrate the microscopic parameters required by the model,and the reliability of the model is verified by comparing with the experimental results.Furthermore,a coupled finite difference method-discrete element method approach is used to construct the model of the split Hopkinson pressure bar.Compression tests are simulated on SFRC specimens with varying steel fiber contents under static and dynamic loading conditions.Finally,based on the advantages of DEM analysis at the mesoscopic level,this study analyzed mechanisms of enhancement and crack arrest in SFRC.It shed a light on the perspectives of interface failure process,microcrack propagation,contact force field evolution and energy analysis,offering valuable insights for related mining engineering applications.展开更多
Driven by technological innovation and the innovative allocation of production factors,new quality productive forces(NQPFs)are a key breakthrough and core element propelling China’s transition from a major agricultur...Driven by technological innovation and the innovative allocation of production factors,new quality productive forces(NQPFs)are a key breakthrough and core element propelling China’s transition from a major agricultural country to an advanced agricultural nation.At its core,agricultural modernization represents a frontier shift in agricultural development-a dynamic evolution of productive forces across technological forms,farmer demographics,industrial structures,and urban-rural relations.NQPFs drive the high-quality,integrated development of agricultural modernization through agricultural technological innovation,green and low-carbon practices,and the enhancement of all production factors.As NQPFs evolve and agricultural modernization advances,we must address constraints stemming from gaps in technology,models,resources,and talent.Furthermore,we must foster deep integration among industry,research,and education to develop new pathways for industrial upgrading,promote green and efficient agricultural development,and bridge existing technological gaps.These collective efforts are crucial for accelerating the high-quality development of agricultural modernization.展开更多
Digital modeling and autonomous control of the die forging process are significant challenges in realizing high-quality intelli-gent forging of components.Using the die forging of AA2014 aluminum alloy as a case study...Digital modeling and autonomous control of the die forging process are significant challenges in realizing high-quality intelli-gent forging of components.Using the die forging of AA2014 aluminum alloy as a case study,a machine-learning-assisted method for di-gital modeling of the forging force and autonomous control in response to forging parameter disturbances was proposed.First,finite ele-ment simulations of the forging processes were conducted under varying friction factors,die temperatures,billet temperatures,and for-ging velocities,and the sample data,including process parameters and forging force under different forging strokes,were gathered.Pre-diction models for the forging force were established using the support vector regression algorithm.The prediction error of F_(f),that is,the forging force required to fill the die cavity fully,was as low as 4.1%.To further improve the prediction accuracy of the model for the ac-tual F_(f),two rounds of iterative forging experiments were conducted using the Bayesian optimization algorithm,and the prediction error of F_(f) in the forging experiments was reduced from 6.0%to 1.5%.Finally,the prediction model of F_(f) combined with a genetic algorithm was used to establish an autonomous optimization strategy for the forging velocity at each stage of the forging stroke,when the billet and die temperatures were disturbed,which realized the autonomous control in response to disturbances.In cases of−20 or−40℃ reductions in the die and billet temperatures,forging experiments conducted with the autonomous optimization strategy maintained the measured F_(f) around the target value of 180 t,with the relative error ranging from−1.3%to+3.1%.This work provides a reference for the study of di-gital modeling and autonomous optimization control of quality factors in the forging process.展开更多
Due to batteries inconsistencies and potential faults in battery management systems,slight overcharging remains a common yet insufficiently understood safety risk,lacking effective warning methods.To illuminate the de...Due to batteries inconsistencies and potential faults in battery management systems,slight overcharging remains a common yet insufficiently understood safety risk,lacking effective warning methods.To illuminate the degradation behavior and failure mechanism of various overcharged states(100%SOC,105%SOC,110%SOC,and 115%SOC),multiple advanced in-situ characterization techniques(accelerating rate calorimeter,electrochemical impedance spectroscopy,ultrasonic scanning,and expansion instrument)were utilized.Additionally,re-overcharge-induced thermal runaway(TR)tests were conducted,with a specific emphasis on the evolution of the expansion force signal.Results indicated significant degradation at 110%SOC including conductivity loss,loss of lithium inventory,and loss of active material accompanied by internal gas generation.These failure behaviors slow down the expansion force rate during reovercharging,reducing the efficacy of active warnings that depend on rate thresholds of expansion force.Specifically,the warning time for 115%SOC battery is only 144 s,which is 740 s shorter than that for fresh battery,and the time to TR is advanced by 9 min.Moreover,the initial self-heating temperature(T1)is reduced by 62.4℃compared to that of fresh battery,reaching only 70.8℃.To address the low safety of overcharged batteries,a passive overcharge warning method utilizing relaxation expansion force was proposed,based on the continued gas generation after stopping charging,leading to a sustained increase in force.Compared to active methods that rely on thresholds of expansion force rate,the passive method can issue warnings 115 s earlier.By combining the passive and active warning methods,guaranteed effective overcharge warning can be issued 863-884 s before TR.This study introduces a novel perspective for enhancing the safety of batteries.展开更多
A new analytical model for geometric size and forming force prediction in incremental flanging(IF)is presented in this work.The complex deformation characteristics of IF are considered in the modeling process,which ca...A new analytical model for geometric size and forming force prediction in incremental flanging(IF)is presented in this work.The complex deformation characteristics of IF are considered in the modeling process,which can accurately describe the strain and stress states in IF.Based on strain analysis,the model can predict the material thickness distribution and neck height after IF.By considering contact area,strain characteristics,material thickness changes,and friction,the model can predict specific moments and corresponding values of maximum axial forming force and maximum horizontal forming force during IF.In addition,an IF experiment involving different tool diameters,flanging diameters,and opening hole diameters is conducted.On the basis of the experimental strain paths,the strain characteristics of different deformation zones are studied,and the stable strain ratio is quantitatively described through two dimensionless parameters:relative tool diameter and relative hole diameter.Then,the changing of material thickness and forming force in IF,and the variation of minimum material thickness,neck height,maximum axial forming force,and maximum horizontal forming force with flanging parameters are studied,and the reliability of the analytical model is verified in this process.Finally,the influence of the horizontal forming force on the tool design and the fluctuation of the forming force are explained.展开更多
基金Project(52078129)supported by the National Natural Science Foundation of ChinaProject(MTF2023009)supported by the Open Project of Key Laboratory of Transport Industry of Comprehensive Transportation Theory(Nanjing Modern Multimodal Transportation Laboratory),ChinaProject(2242024K40037)supported by the Fundamental Research Funds for the Central Universities,China。
文摘A shaking table test was performed to investigate the different responses of piles with and without cement-soil reinforcement,considering both inertial and kinematic interactions.A comparison of the dynamic shear stress−strain hysteresis curves of soil profiles on the pile side with and without cement-soil reinforced piles indicates that cement-soil reinforced piles not only bear more tremendous shear stress but also have smaller strains under the action of cyclic shear stress.Furthermore,the cement-soil on the pile side not only shares part of the shear stress and modifies the bending moment distribution but also significantly enhances the resistance of the pile-side soil,reducing the lateral displacement of the superstructure.Cement-soil reinforcement reduced shear strains,inhibited sand liquefaction,and reduced superstructure displacements by 27%−47%(instantaneous)and 40%−65%(permanent).The proportion of horizontal load sharing between cement-soil reinforcement and saturated sand is considered,along with the change pattern of the subgrade reaction after sand liquefaction.An equivalent subgrade reaction calculation method is proposed,which accounts for the horizontal load-sharing ratios of soils with two different strengths.The test results indicate that the pile stress and displacement,estimated using the equivalent subgrade reaction,are in good agreement with the observed results.
基金co-supported by the National Natural Science Foundation of China(No.52125504)the Liaoning Revitalization Talents Program(No.XLYC2202017)Dalian Support Policy Project for Innovation of Technological Talents(No.2023RG001)。
文摘The high-quality assembly of Large Aircraft Components(LACs)is essential in modern aviation manufacturing.Numerical control locators are employed for the posture adjustment of LAC,yet the system's multi-input multi-output,nonlinearity,and strong coupling presents significant challenges.The substantial internal force generated during the adjustment process can potentially damage the LAC and degrade the assembly quality.Hence,a workspace-based hybrid force position control scheme was developed to achieve high quality assembly with high-precision and lower internal force.Firstly,an offline workspace analysis with inherent geometric characteristics to form time-varying posture error constraint.Then,the posture error is integrated into the online position axis control to ensure tracking the ideal posture,while the force control axis compensates for posture deviation by minimizing internal force,thereby achieving high precision and low internal force.Finally,the effectiveness was demonstrated through experiments.The root mean square errors of orientation and position are 104 rad and 0.1 mm,respectively.A reduction in internal force can range from 10.96%to 57.4%compared to the traditional method.Key points'max position error is decreased from 0.32 mm to 0.18 mm,satisfying the 0.5 mm tolerance.Therefore,the proposed method will help promote the development of high-performance manufacturing.
基金financial support by the National Key Research and Development Program of China(No.2023YFC2907801)the Hunan Provincial Natural Science Foundation of China(No.2023JJ40760)the Scientific and Technological Project of Yunnan Precious Metals Laboratory,China(No.YPML-2023050276)。
文摘Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pellets.Addressing the gap in the application of organically-intercalated modified bentonite in the pelletizing field,this study introduces an innovative modification process for bentonite that employs the synergistic effect of mechanical force and dimethyl sulfoxide to enhance the intercalation of organic compounds within bentonite,thus significantly enhancing its binding performance.The colloid value and swell capacity of modified bentonite(98.5 m L/3g and 55.0 m L/g)were much higher than the original bentonite(90.5 m L/3g and 17.5 m L/g).With the decrease of bentonite dosage from1.5wt%to 1.0wt%,the drop number of green pellets from a height of 0.5 m and the compressive strengths of roasted pellets using the modified bentonite(6.0 times and 2916 N per pellet)were significantly higher than those of the original bentonite(4.0 times and 2739 N per pellet).This study provides a comprehensive analysis of the intercalation modification mechanism of bentonite,offering crucial technical insights for the development of high-performance modified bentonite as iron ore pellet binders.
基金Supported by Key Project of Jiangsu Education Science Planning"Research on the Structural Adjustment of Higher Education in Jiangsu in the Context of High-Quality Economic Development"(B/2021/01/67).
文摘In the context of the coordinated pursuit of"carbon peak and neutrality"objectives,alongside the strategy to establish a robust agricultural nation,the economic and social development of rural areas is undergoing a profound paradigm shift.The traditional rural division of labor pattern,which depends on tangible factors such as land,labor,and capital,has increasingly encountered developmental challenges characterized by diminishing marginal returns and a detrimental cycle of internal competition.The new quality productive force,centered on data,algorithms,green technologies,bioengineering,and clean energy,offers a potential pathway for the rural division of labor system to overcome the"low-level equilibrium".This force is characterized by attributes such as non-exclusivity,replicability,network collaboration,and ecological compatibility.This paper develops a three-dimensional collaborative analytical framework encompassing"technology,institution,and culture".It systematically elucidates the internal logic by which new quality productive forces drive the transformation of the rural division of labor from"quantitative factor matching"to"qualitative structural reorganization"through three principal mechanisms:technology embedding,institutional reconstruction,and cultural coupling.Furthermore,the study proposes corresponding policy recommendations,thereby offering theoretical insights to support the modernization of China s agriculture and rural areas,as well as the development of a strong agricultural country.
基金supported by the National Natural Science Foundation of China (Grant Nos.52505554,52575571)the Postdoctoral Fellowship Program of CPSF (Grant No.GZB20250348)。
文摘Accurate mechanical modeling is essential for robotic belt grinding(RBG), a process characterized by compliant contact mechanisms that make force prediction particularly challenging. However, existing mechanical models predominantly focus on macroscale compliance while neglecting grain-scale compliant motion. Moreover, abrasive grains are typically idealized as regular shapes, overlooking the inherent stochasticity of real grain geometries. This study proposes a shapeequivalence method for modeling stochastic abrasive grains and develops a multiscale compliant force model for RBG. Specifically, an individual grain is represented as a polygonal pyramid with stochastic edges that is mathematically equivalent to a cone;this method unifies the treatment of grain geometries and streamlines the modeling process. The mathematical equivalence relationship for random grain shapes is further derived based on a grain-compliant contact model. By integrating grain geometric characteristics and progressive grain wear, an analytical mechanical model that captures both the static contact force and dynamic grinding force is established, thereby describing the transition from grain-workpiece compliant interaction to belt-workpiece elastic contact. Grinding experiments were conducted using abrasive belts with different grain shape distributions to validate the model. The results demonstrated reliable predictions of the tangential grinding force and its component characteristics. Additional analyses were performed to reveal how the tangential grinding force varies with wear time and grinding parameters.
基金supported by the Natural Science Foundation of Shaanxi Province(2023-JC-QN-0728)the China Postdoctoral Science Foundation(2021M693942)。
文摘Manned aerial vehicle-unmanned aerial vehicle(MAV-UAV)combat organization is a MAV-UAV combat collective formed from the perspective of organization design theory and methodology,and the generation of force formation plan is a key step in the organizational planning.Based on the description of the problem and the definition of organizational elements,the matching model of platform-target attack wave is constructed to minimize the redundancy of command and decision-making capability,resource capability and the number of platforms used.Based on the non-dominated sorting genetic algorithmⅢ(NSGA-Ⅲ)framework,which includes encoding/decoding method and constraint handling method,the generation model of organizational force formation plan is solved,and the effectiveness and superiority of the algorithm are verified by simulation experiments.
文摘Sandwich functionally graded(FG)auxetic beams are extensively utilized in aerospace,automotive,and biomedical industries due to their excellent strength-toweight ratio,impact resistance,and tunable mechanical properties.The integration of FG materials with auxetic structures enhances their adaptability in advanced engineering applications.However,understanding their dynamic behavior under external excitations is essential for optimal design and structural reliability.Nonlinear interactions in such structures pose significant challenges in vibration analysis,necessitating robust analytical methods.This study presents a closed-form solution for the nonlinear forced vibration analysis of sandwich FG auxetic beams,offering an accurate and efficient method for predicting their dynamic response.The beam consists of two FG face sheets with material properties varying through the thickness and a re-entrant honeycomb auxetic core with an adjustable Poisson's ratio.The governing nonlinear equations of motion are derived using the first-order shear deformation theory(FSDT),the modified Gibson model,and the von Kármán relations,formulated through Hamilton's principle.A closed-form solution is obtained via the Galerkin method and multiple-scale technique.The results demonstrate that FG layers enable control of the overweight and dynamic response amplitude,with positive power law indexes reducing weight.Comparisons with finite element results confirm the accuracy of the proposed formulation.
基金financially supported by the National Natural Science Foundation of China(Nos.52272160,U2330112,and 52002254)Sichuan Science and Technology Foundation(Nos.2020YJ0262,2021YFH0127,2022YFH0083,2022YFSY0045,and 2023YFSY0002)+1 种基金the Chunhui Plan of Ministry of Education,Fundamental Research Funds for the Central Universities,China(No.YJ201893)the Foundation of Key Laboratory of Lidar and Device,Sichuan Province,China(No.LLD2023-006)。
文摘Nowadays,force sensors play an important role in industrial production,electronic information,medical health,and many other fields.Two-dimensional material-based filed effect transistor(2D-FET)sensors are competitive with nano-level size,lower power consumption,and accurate response.However,few of them has the capability of impulse detection which is a path function,expressing the cumulative effect of the force on the particle over a period of time.Herein we fabricated the flexible polymethyl methacrylate(PMMA)gate dielectric MoS_(2)-FET for force and impulse sensor application.We systematically investigated the responses of the sensor to constant force and varying forces,and achieved the conversion factors of the drain current signals(I_(ds))to the detected impulse(I).The applied force was detected and recorded by I_(ds)with a low power consumption of~30 nW.The sensitivity of the device can reach~8000%and the 4×1 sensor array is able to detect and locate the normal force applied on it.Moreover,there was almost no performance loss for the device as left in the air for two months.
文摘Astronomical extreme events or phenomena include black holes as well as nebulae systems that resemble the Milky Way. Meteorological extreme events or phenomena include tornadoes and tropical cyclones. The new high energy state of matter expanding outwards by spin jets from the two poles of an astronomical black hole, the new high energy state of matter in a funnel-shaped vortex showed a meteorological tornado expanding downwards from a rotated disk of cumulonimbus clouds, the new high energy state of matter in a tropical cyclone and the new high energy state of a nebulae system converging celestial materials are phenomena across disciplines and multiple time-space scales that have not yet been physically explained. In this paper, the theory of orthogonal collision in the rotational contraction continuum is used to unify the understanding of diverse extreme events or phenomena through a single dynamical mechanism, offering insights into natural processes across disciplines. In the field of astronomy, the orthogonal collision of two-beam rotating and contracting particles or stars associated with centripetal forces forms a new high-energy state of matter at the collision point and the new high-energy particles have expanding forces outward to both sides of the collision plane. In the field of meteorology, the orthogonal collision of multiple horizontally rotating and contracting airflows associated with centripetal forces forms a new high energy state of matter at the collision point as well as an updraft force and a downdraft force vertically. The updraft force and downdraft force formed by the collision of anomalous wet airflows in the lower atmosphere can well indicate tornado, thunderstorm and extreme precipitation. The orthogonal collision theory can be applied to explain new states of matter in disciplines from the astronomical scale to the meteorological scale and the Planck scale.
文摘Soft robots,as a modern gateway to unlocking the mysteries of underwater realms,present new complexities.Modeling their behavior when in contact with external forces,whether point-based or distributed,is a primary challenge due to the nature of soft bodies.To obtain a holistic view of the system’s behavior determining the governing dynamics is deemed necessary.This paper proposes a new technique to simulate the dynamic lateral undulation of a soft robotic fish with a cable-driven soft tail.By integrating the rigid finite element method with rigid-body robotics,the model represents the undulation of a finite number of rigid elements connected through a set of torsional spring and damper.Instead of directly modeling external forces,we substitute equivalent joint torques into the system dynamics,allowing us to consider external effects without complicating the model.The resulting model yields valuable insights into the system’s behavior,including propulsive and lateral forces.A comparison with experimental results shows strong agreement,with a tip amplitude error of 10% at 0.8 Hz,5.25% at 1.6 Hz and 2.54%at 2.2 Hz flapping frequency.These findings illuminate the influence of lateral undulation on the overall dynamics,paving the way for fully autonomous robotic fish.
基金Supported by National Nature Science Foundation of China(Grant Nos.52205225,U2330202)The Foundation Project of China(Grant No.2023-JCJQ-JJ-0958).
文摘With the intensification of lunar exploration,the failure risk caused by the adsorption of lunar dust on the spacecraft surface cannot be ignored.Therefore,three types of typical spatial solid lubrication films,namely polytetrafluoroethylene(PTFE),amorphous carbon(a-C)and molybdenum disulfide(MoS2),were prepared as test samples.Firstly,the surface free energy parameters of the material were measured using a contact Angle measuring instrument.At the same time,atomic force microscopy(AFM)was used to quantify the adhesion of the film samples based on the lunar dust micro-adsorption model.In order to investigate the influence of the test environment,the environmental pressure was adjusted to normal pressure environment and high vacuum environment with a vacuum degree of 10−6 Pa for testing.The results indicate a positive correlation between surface energy and adhesion.As surface energy increases,molecules tend to move closer,forming a stronger attraction and thus enhancing surface adhesion.In addition,AFM was used to measure the adhesion force under atmospheric pressure and vacuum conditions,revealing that parameters measured in atmospheric environment were generally higher than those measured in vacuum,which effectively verified the existence of capillary force in the microscopic adsorption model and its influence on the adhesion effect.Through the test comparison of three groups of typical solid lubricating films,it is found that MoS2 has a lower adhesion effect than the other two groups of films,which can effectively reduce the adhesion phenomenon of lunar dust on the surface of the material,and provide suitable materials for future lunar exploration and manned lunar missions.
基金support by Hong Kong RGC General Research Fund(16217824,16213825,16203923,and 16217824)National Natural Science Foundation of China(N_HKUST638/23)+1 种基金Research Grants Council Joint Research Scheme(62361166630)Guangdong Basic and Applied Basic Research Foundation(2023B1515130007).
文摘Human skin exhibits a remarkable capability to perceive contact forces and environmental temperatures,providing complex information that is essential for its subtle control.Despite recent advancements in soft tactile sensors,accurately decoupling signals—specifically separating forces from directional orientation and temperature—remains a challenge thus resulting in failure to meet the advanced application requirements of robots.This study proposes,F3T,a multilayer soft sensor unit designed to achieve isolated measurements and mathematical decoupling of normal pressure,omnidirectional tangential forces,and temperature.We developed a circular coaxial magnetic film featuring a floating mount multilayer capacitor that facilitated the physical decoupling of normal and tangential forces in all directions.Additionally,we incorporated an ion gel-based temperature-sensing film into the tactile sensor.The proposed sensor was resilient to external pressures and deformations,and could measure temperature and significantly eliminate capacitor errors induced by environmental temperature changes.In conclusion,our novel design allowed for the decoupled measurement of multiple signals,laying the foundation for advancements in high-level robotic motion control,autonomous decision-making,and task planning.
基金supported by the Ministry of Science and Higher Education of the Russian Federation(No.075-15-2024-535)。
文摘The purpose of this article is to provide,from the perspective of deformable solid mechanics,a correct justification for the expressions of all forces acting on the surface of a ferromagnetic material in a magnetic field,initiated only by this field.It is shown that the moment of force applied to any closed body surface S,corresponding to the asymmetric part TAof the stress tensor T(denoted as the force pA),balances the mass magnetic moment Lmagacting in the volume V bounded by the surface S.The emergence of the asymmetric part TAof the stress tensor arises as a consequence of a special case within the moment theory of elasticity,the use of which is necessary for accurately describing the behavior of a ferromagnetic material in a magnetic field.The force pa acts in a plane tangential to the surface S at any point,while,in addition to this force,the normal force pn also acts on the body surface.It is shown in the article that the latter force arises as a result of a jump in the normal component of the magnetic field strength appearing at the body surface,and its expression is defined by the mass' s(ponderomotive) magnetic forces Fmag.Usually,this force is introduced based on the Maxwell stress tensor,which is used in the classical electromagnetism to represent the interaction between electromagnetic forces and mechanical momentum.However,as we believe and justify this in the article,such an approach is unacceptable in deformable solid mechanics.
基金supported by the National Key Research and Development Program of China(Grant Nos.2022YFA1403300 and 2019YFA0308404)the National Natural Science Foundation of China(Grant Nos.11427902,11991060,12074075,12474165,12274084,and 12241402)+5 种基金Shanghai Municipal Science and Technology Major Project(Grant No.2019SHZDZX01)Shanghai Municipal Natural Science Foundation(Grant No.22ZR1407400)Innovation Program for Quantum Science and Technology(Grant No.2024ZD0300104)Innovation Program of Shanghai Municipal Education Commission(Grant No.2023ZKZD03)Science and Technology Commission of Shanghai Municipality(Grant No.20JC1415900)China Postdoctoral Science Foundation(Grant No.KLH1512149).
文摘Recently,charged solitons have been found in a two-dimensional CoCl_(2)/HOPG system,whose microscopic nature remains to be elusive.In this work,we investigate the charged solitons in monolayer CoCl_(2) using scanning tunneling microscopy(STM)and atomic force microscopy(AFM).Moreover,we study the electrical properties of the charged solitons at zero electric field by measuring local contact potential difference(LCPD)via Kelvin probe force microscopy(KPFM)using the Δf(V)method.The compensation voltage corresponding to the vertex of the parabola is obtained by fitting the quadratic relationship between Δf and sample bias.The results show that,without an external electric field,the solitons behave as negatively charged entities.Meanwhile,the LCPD mapping characterizes the spatial distribution of the potential at the charged solitons,which agrees well with those obtained from STM band bending measurements.
基金supported by the Ningbo Youth Science and Technology Innovation Leading Talents of China(No.2023QL020)the Ningbo Science and Technology Major of China(No.2022Z015)the K.C.Wong Magana Fund through Ningbo University。
文摘This study presents a closed-form solution for central stress,a semi-analytical model,and a modified anisotropic semi-analytical model to efficiently calculate the forcefrequency coefficients(FFCs)of square quartz crystal resonators(QCRs)with different side lengths and azimuth angles under eccentrically concentrated and distributed loads.The semi-analytical model is validated by comparisons between the experimental results and the nonlinear finite element method(FEM)simulation results.Based on the semi-analytical model for the FFC and nonlinear FEM simulations,the FFC variations of square QCRs under external loads and the related mechanisms are investigated.Among the initial stresses caused by external loads,the central stress parallel to the xcrystallographic axis is the primary factor influencing the FFC of quartz.Our findings can provide practical tools for calculating the FFC,and help the design and development of square quartz force sensors.
基金financial support by the National Natural Science Foundation of China(52174101&52408310)Guangdong Basic and Applied Basic Research Foundation(2023A1515011634&2024A1515012528)Guangdong Provincial Department of Science and Technology(2021ZT09G087)for the research.
文摘The frequent or occasional impact loads pose serious threats to the service safety of conventional concrete structures in tunnel.In this paper,a novel three-dimensional mesoscopic model of steel fiber reinforced concrete(SFRC)is constructed by discrete element method.The model encompasses the concrete matrix,aggregate,interfacial transition zone and steel fibers,taking into account the random shape of the coarse aggregate and the stochastic distribution of steel fibers.It captures microscopic-level interactions among the coarse aggregate,steel fibers,and matrix.Subsequently,a comprehensive procedure is formulated to calibrate the microscopic parameters required by the model,and the reliability of the model is verified by comparing with the experimental results.Furthermore,a coupled finite difference method-discrete element method approach is used to construct the model of the split Hopkinson pressure bar.Compression tests are simulated on SFRC specimens with varying steel fiber contents under static and dynamic loading conditions.Finally,based on the advantages of DEM analysis at the mesoscopic level,this study analyzed mechanisms of enhancement and crack arrest in SFRC.It shed a light on the perspectives of interface failure process,microcrack propagation,contact force field evolution and energy analysis,offering valuable insights for related mining engineering applications.
基金funded by grants from the General Project of the National Social Science Fund:“Research on the Interactive Mechanism of Migrant Workers Returning to Their Hometowns for Entrepreneurship and Rural Revitalization in the Major Labor Export Provinces”(20BJY136)General Project of Sichuan Provincial Philosophy and Social Science Fund:“The Era Significance,Growth Constraints,and Path Optimization of the New Agricultural Laborers from the Perspective of the New Quality Productive Forces”(SCJJ24ND065)Key Project of the Sichuan Academy of Social Sciences:“The Era Significance,Current Concerns,and Action Prospects of the New Agricultural Laborers from the Perspective of the New Quality Productive Forces”(24XD02).
文摘Driven by technological innovation and the innovative allocation of production factors,new quality productive forces(NQPFs)are a key breakthrough and core element propelling China’s transition from a major agricultural country to an advanced agricultural nation.At its core,agricultural modernization represents a frontier shift in agricultural development-a dynamic evolution of productive forces across technological forms,farmer demographics,industrial structures,and urban-rural relations.NQPFs drive the high-quality,integrated development of agricultural modernization through agricultural technological innovation,green and low-carbon practices,and the enhancement of all production factors.As NQPFs evolve and agricultural modernization advances,we must address constraints stemming from gaps in technology,models,resources,and talent.Furthermore,we must foster deep integration among industry,research,and education to develop new pathways for industrial upgrading,promote green and efficient agricultural development,and bridge existing technological gaps.These collective efforts are crucial for accelerating the high-quality development of agricultural modernization.
基金financially supported by the National Key Research and Development Program of China(No.2022YFB3706901)the National Natural Science Foundation of China(No.52090041)the Young Elite Scientists Sponsorship Program by CAST(No.2022QNRC 001).
文摘Digital modeling and autonomous control of the die forging process are significant challenges in realizing high-quality intelli-gent forging of components.Using the die forging of AA2014 aluminum alloy as a case study,a machine-learning-assisted method for di-gital modeling of the forging force and autonomous control in response to forging parameter disturbances was proposed.First,finite ele-ment simulations of the forging processes were conducted under varying friction factors,die temperatures,billet temperatures,and for-ging velocities,and the sample data,including process parameters and forging force under different forging strokes,were gathered.Pre-diction models for the forging force were established using the support vector regression algorithm.The prediction error of F_(f),that is,the forging force required to fill the die cavity fully,was as low as 4.1%.To further improve the prediction accuracy of the model for the ac-tual F_(f),two rounds of iterative forging experiments were conducted using the Bayesian optimization algorithm,and the prediction error of F_(f) in the forging experiments was reduced from 6.0%to 1.5%.Finally,the prediction model of F_(f) combined with a genetic algorithm was used to establish an autonomous optimization strategy for the forging velocity at each stage of the forging stroke,when the billet and die temperatures were disturbed,which realized the autonomous control in response to disturbances.In cases of−20 or−40℃ reductions in the die and billet temperatures,forging experiments conducted with the autonomous optimization strategy maintained the measured F_(f) around the target value of 180 t,with the relative error ranging from−1.3%to+3.1%.This work provides a reference for the study of di-gital modeling and autonomous optimization control of quality factors in the forging process.
基金supported by the National Natural Science Foundation of China(52476200,52106244)the Guangdong Basic and Applied Basic Research Foundation(2024A1515030124)+1 种基金the Science and Technology Project of China Southern Power Grid under Grant GDKJXM20230246(030100KC23020017)the Fundamental Research Funds for the Central Universities。
文摘Due to batteries inconsistencies and potential faults in battery management systems,slight overcharging remains a common yet insufficiently understood safety risk,lacking effective warning methods.To illuminate the degradation behavior and failure mechanism of various overcharged states(100%SOC,105%SOC,110%SOC,and 115%SOC),multiple advanced in-situ characterization techniques(accelerating rate calorimeter,electrochemical impedance spectroscopy,ultrasonic scanning,and expansion instrument)were utilized.Additionally,re-overcharge-induced thermal runaway(TR)tests were conducted,with a specific emphasis on the evolution of the expansion force signal.Results indicated significant degradation at 110%SOC including conductivity loss,loss of lithium inventory,and loss of active material accompanied by internal gas generation.These failure behaviors slow down the expansion force rate during reovercharging,reducing the efficacy of active warnings that depend on rate thresholds of expansion force.Specifically,the warning time for 115%SOC battery is only 144 s,which is 740 s shorter than that for fresh battery,and the time to TR is advanced by 9 min.Moreover,the initial self-heating temperature(T1)is reduced by 62.4℃compared to that of fresh battery,reaching only 70.8℃.To address the low safety of overcharged batteries,a passive overcharge warning method utilizing relaxation expansion force was proposed,based on the continued gas generation after stopping charging,leading to a sustained increase in force.Compared to active methods that rely on thresholds of expansion force rate,the passive method can issue warnings 115 s earlier.By combining the passive and active warning methods,guaranteed effective overcharge warning can be issued 863-884 s before TR.This study introduces a novel perspective for enhancing the safety of batteries.
基金supported in part by financial support from the National Key R&D Program of China(No.2023YFB3407003)the National Natural Science Foundation of China(No.52375378).
文摘A new analytical model for geometric size and forming force prediction in incremental flanging(IF)is presented in this work.The complex deformation characteristics of IF are considered in the modeling process,which can accurately describe the strain and stress states in IF.Based on strain analysis,the model can predict the material thickness distribution and neck height after IF.By considering contact area,strain characteristics,material thickness changes,and friction,the model can predict specific moments and corresponding values of maximum axial forming force and maximum horizontal forming force during IF.In addition,an IF experiment involving different tool diameters,flanging diameters,and opening hole diameters is conducted.On the basis of the experimental strain paths,the strain characteristics of different deformation zones are studied,and the stable strain ratio is quantitatively described through two dimensionless parameters:relative tool diameter and relative hole diameter.Then,the changing of material thickness and forming force in IF,and the variation of minimum material thickness,neck height,maximum axial forming force,and maximum horizontal forming force with flanging parameters are studied,and the reliability of the analytical model is verified in this process.Finally,the influence of the horizontal forming force on the tool design and the fluctuation of the forming force are explained.
