A flexible multi-body model of a surface miner for analyzing the interaction between rock-cutting forces and chassis vibrations

The discontinuous nature of rock cutting can easily cause unwanted vibrations in the structure of a surface miner.If these vibrations are not properly addressed,the related stress cycles can gradually damage the chassis resulting in fatigue failures.These events can seriously undermine the safety of operators and digging operations may be stopped for days,with an obvious economic impact.This work presents an analysis of the dynamics of a surface miner,focusing on the interaction between cutting machine dynamics and cutting forces,which is a new approach for this type of machine.For this purpose,the authors developed a numerical model of the cutting process made up of(1)a multi-body model of the cutting machine,which takes into account the chassis's flexibility;(2)a model of the rotating cutting head;and(3)a model of the interaction between the cutting head and rock,based on Shao's model.The model was compared with experimental results and then used to investigate the effects of cutting speed and cutting depth on the machine dynamics.

Articulated Lifting System Modeling Based on Dynamics of Flexible Multi-Body Systems

In lifting sub-system of deep-sea mining system, spherical joint is used to connect lifting pipes to replace fixed joint. Based on Dynamics of Flexible Multi-body systems, the mechanics model of articulated lifting system is established. Under the four-grade and six-grade oceanic condition, dynamic responses of lifting system are simulated and experiment verified. The simulation results are consistent with experimental ones. The maximum moment of flexion is 322 kN-m on the first pipe under six-grade sea condition. It is seen that the articulated connection can reduce the moment of flexion. The bending deformation of pipe center is researched, and the maximum is 0. 000479 m on the first pipe. Deformation has a little effect on the motion of system. It is feasible to analyze articulated lifting system by applying the theory of flexible multi-body dynamics. The articulated lifting system is obviously better than the fixed one.

An efficient formulation based on the Lagrangian method for contact–impact analysis of flexible multi-body system

In this paper,an efficien formulation based on the Lagrangian method is presented to investigate the contact–impact problems of f exible multi-body systems.Generally,the penalty method and the Hertz contact law are the most commonly used methods in engineering applications.However,these methods are highly dependent on various non-physical parameters,which have great effects on the simulation results.Moreover,a tremendous number of degrees of freedom in the contact–impact problems will influenc thenumericalefficien ysignificantl.Withtheconsideration of these two problems,a formulation combining the component mode synthesis method and the Lagrangian method is presented to investigate the contact–impact problems in fl xible multi-body system numerically.Meanwhile,the finit element meshing laws of the contact bodies will be studied preliminarily.A numerical example with experimental verificatio will certify the reliability of the presented formulationincontact–impactanalysis.Furthermore,aseries of numerical investigations explain how great the influenc of the finit element meshing has on the simulation results.Finally the limitations of the element size in different regions are summarized to satisfy both the accuracy and efficien y.

Investigation on the choice of boundary conditions and shape functions for flexible multi-body system

The objective of this investigation is to examine the correctness and efficiency of the choice of boundary conditions when using assumed mode approach to simulate flexible multi-body systems. The displacement field due to deformation is approximated by the Rayleigh-Ritz assumed modes in floating frame of reference （FFR） formulation. The deformations obtained by the absolute nodal coordinate （ANC） formulation which are transformed by two sets of reference coordinates are introduced as a criterion to verify the accuracy of the simulation results by using the FFR formulation. The relationship between the deformations obtained from different boundary conditions is revealed. Nu- merical simulation examples demonstrate that the assumed modes with cantilevered-free, simply-supported and free- free boundary conditions without inclusion of rigid body modes are suitable for simulation of flexible multi-body system with large over all motion, and the same physical deformation can be obtained using those mode functions, differ only by a coordinate transformation. It is also shown that when using mode shapes with statically indeterminate boundary conditions, significant error may occur. Furthermore, the slider crank mechanism with rigid crank is accurate enough for investigating boundary condition problem of flexible multi-body system, which cost significant less simulating time.

Flexible Graphene Field‑Effect Transistors and Their Application in Flexible Biomedical Sensing

Flexible electronics are transforming our lives by making daily activities more convenient.Central to this innovation are field-effect transistors(FETs),valued for their efficient signal processing,nanoscale fabrication,low-power consumption,fast response times,and versatility.Graphene,known for its exceptional mechanical properties,high electron mobility,and biocompatibility,is an ideal material for FET channels and sensors.The combination of graphene and FETs has given rise to flexible graphene field-effect transistors(FGFETs),driving significant advances in flexible electronics and sparked a strong interest in flexible biomedical sensors.Here,we first provide a brief overview of the basic structure,operating mechanism,and evaluation parameters of FGFETs,and delve into their material selection and patterning techniques.The ability of FGFETs to sense strains and biomolecular charges opens up diverse application possibilities.We specifically analyze the latest strategies for integrating FGFETs into wearable and implantable flexible biomedical sensors,focusing on the key aspects of constructing high-quality flexible biomedical sensors.Finally,we discuss the current challenges and prospects of FGFETs and their applications in biomedical sensors.This review will provide valuable insights and inspiration for ongoing research to improve the quality of FGFETs and broaden their application prospects in flexible biomedical sensing.

Force and impulse multi-sensor based on flexible gate dielectric field effect transistor

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.

Ultra‑Transparent and Multifunctional IZVO Mesh Electrodes for Next‑Generation Flexible Optoelectronics

Mechanically durable transparent electrodes are essential for achieving long-term stability in flexible optoelectronic devices.Furthermore,they are crucial for applications in the fields of energy,display,healthcare,and soft robotics.Conducting meshes represent a promising alternative to traditional,brittle,metal oxide conductors due to their high electrical conductivity,optical transparency,and enhanced mechanical flexibility.In this paper,we present a simple method for fabricating an ultra-transparent conducting metal oxide mesh electrode using selfcracking-assisted templates.Using this method,we produced an electrode with ultra-transparency(97.39%),high conductance(Rs=21.24Ωsq^(−1)),elevated work function(5.16 eV),and good mechanical stability.We also evaluated the effectiveness of the fabricated electrodes by integrating them into organic photovoltaics,organic light-emitting diodes,and flexible transparent memristor devices for neuromorphic computing,resulting in exceptional device performance.In addition,the unique porous structure of the vanadium-doped indium zinc oxide mesh electrodes provided excellent flexibility,rendering them a promising option for application in flexible optoelectronics.

A Flexible Smart Healthcare Platform Conjugated with Artificial Epidermis Assembled by Three‑Dimensionally Conductive MOF Network for Gas and Pressure Sensing

The rising flexible and intelligent electronics greatly facilitate the noninvasive and timely tracking of physiological information in telemedicine healthcare.Meticulously building bionic-sensitive moieties is vital for designing efficient electronic skin with advanced cognitive functionalities to pluralistically capture external stimuli.However,realistic mimesis,both in the skin’s three-dimensional interlocked hierarchical structures and synchronous encoding multistimuli information capacities,remains a challenging yet vital need for simplifying the design of flexible logic circuits.Herein,we construct an artificial epidermal device by in situ growing Cu_(3)(HHTP)_(2) particles onto the hollow spherical Ti_(3)C_(2)T_(x) surface,aiming to concurrently emulate the spinous and granular layers of the skin’s epidermis.The bionic Ti_(3)C_(2)T_(x)@Cu_(3)(HHTP)_(2) exhibits independent NO_(2) and pressure response,as well as novel functionalities such as acoustic signature perception and Morse code-encrypted message communication.Ultimately,a wearable alarming system with a mobile application terminal is self-developed by integrating the bimodular senor into flexible printed circuits.This system can assess risk factors related with asthmatic,such as stimulation of external NO_(2) gas,abnormal expiratory behavior and exertion degrees of fingers,achieving a recognition accuracy of 97.6%as assisted by a machine learning algorithm.Our work provides a feasible routine to develop intelligent multifunctional healthcare equipment for burgeoning transformative telemedicine diagnosis.

Dynamic Investigation on Composite Flexible Multi-body System Considering Thermal Effect

The dynamic performance of composite flexible multi-body system under the simultaneous action of thermal fields and driving constraint is analyzed. Based on strain-displacement relation of the Mindlin plate theory which includes transverse shear deformation, and considering thermal effect, variation equations of laminated plate are derived by the principle of virtual work. The finite element method is used for discretization. According to kinematics constraint relation, dynamic equations for spatial slider-crank system are established. Simulation results show that spatial deformation （torsion deformation） appears in the multi-layered composite slider-crank mechanism which is simulated with planar motions. Furthermore, the influence of coupling between thermal expansion and flexible deformations of non-symmetrical composite plates on the large overall motion under the uniform temperature field is investigated. Finally, significant change in constraint force due to the spatial deformation is shown.

Artificial Intelligence Meets Flexible Sensors:Emerging Smart Flexible Sensing Systems Driven by Machine Learning and Artificial Synapses

The recent wave of the artificial intelligence(AI)revolution has aroused unprecedented interest in the intelligentialize of human society.As an essential component that bridges the physical world and digital signals,flexible sensors are evolving from a single sensing element to a smarter system,which is capable of highly efficient acquisition,analysis,and even perception of vast,multifaceted data.While challenging from a manual perspective,the development of intelligent flexible sensing has been remarkably facilitated owing to the rapid advances of brain-inspired AI innovations from both the algorithm(machine learning)and the framework(artificial synapses)level.This review presents the recent progress of the emerging AI-driven,intelligent flexible sensing systems.The basic concept of machine learning and artificial synapses are introduced.The new enabling features induced by the fusion of AI and flexible sensing are comprehensively reviewed,which significantly advances the applications such as flexible sensory systems,soft/humanoid robotics,and human activity monitoring.As two of the most profound innovations in the twenty-first century,the deep incorporation of flexible sensing and AI technology holds tremendous potential for creating a smarter world for human beings.

An Environment‑Tolerant Ion‑Conducting Double‑Network Composite Hydrogel for High‑Performance Flexible Electronic Devices

High-performance ion-conducting hydrogels(ICHs)are vital for developing flexible electronic devices.However,the robustness and ion-conducting behavior of ICHs deteriorate at extreme tempera-tures,hampering their use in soft electronics.To resolve these issues,a method involving freeze–thawing and ionizing radiation technology is reported herein for synthesizing a novel double-network(DN)ICH based on a poly(ionic liquid)/MXene/poly(vinyl alcohol)(PMP DN ICH)system.The well-designed ICH exhibits outstanding ionic conductivity(63.89 mS cm^(-1) at 25℃),excellent temperature resistance(-60–80℃),prolonged stability(30 d at ambient temperature),high oxidation resist-ance,remarkable antibacterial activity,decent mechanical performance,and adhesion.Additionally,the ICH performs effectively in a flexible wireless strain sensor,thermal sensor,all-solid-state supercapacitor,and single-electrode triboelectric nanogenerator,thereby highlighting its viability in constructing soft electronic devices.The highly integrated gel structure endows these flexible electronic devices with stable,reliable signal output performance.In particular,the all-solid-state supercapacitor containing the PMP DN ICH electrolyte exhibits a high areal specific capacitance of 253.38 mF cm^(-2)(current density,1 mA cm^(-2))and excellent environmental adaptability.This study paves the way for the design and fabrication of high-performance mul-tifunctional/flexible ICHs for wearable sensing,energy-storage,and energy-harvesting applications.

Improved Flexible Triboelectric Nanogenerator Based on Tile-Nanostructure for Wireless Human Health Monitor

Triboelectric nanogenerators(TENGs)have emerged as promising candidates for integrating with flexible electronics as self-powered systems owing to their intrinsic flexibility,biocompatibility,and miniaturization.In this study,an improved flexible TENG with a tile-nanostructured MXene/polymethyl methacrylate(PMMA)composite electrode(MP-TENG)is proposed for use in wireless human health monitor.The multifunctional tile-nanostructured MXene/PMMA film,which is self-assembled through vacuum filtration,exhibits good conductivity,excellent charge capacity,and high flexibility.Thus,the MXene/PMMA composite electrode can simultaneously function as a charge-generating,charge-trapping,and charge-collecting layer.Furthermore,the charge-trapping capacity of a tile nanostructure can be optimized on the basis of the PMMA concentration.At a mass fraction of 4%PMMA,the MP-TENG achieves the optimal output performance,with an output voltage of 37.8 V,an output current of 1.8μA,and transferred charge of 14.1 nC.The output power is enhanced over twofold compared with the pure MXene-based TENG.Moreover,the MP-TENG has sufficient power capacity and durability to power small electronic devices.Finally,a wireless human motion monitor based on the MP-TENG is utilized to detect physiological signals in various kinematic motions.Consequently,the proposed performance-enhanced MP-TENG proves a considerable potential for use in health monitoring,telemedicine,and self-powered systems.

Highly Flexible Graphene-Film-Based Rectenna for Wireless Energy Harvesting

Herein,we report the design,fabrication,and performance of two wireless energy harvesting devices based on highly flexible graphene macroscopic films(FGMFs).We first demonstrate that benefiting from the high conductivity of up to 1×10^(6)S m^(-1)and good resistive stability of FGMFs even under extensive bending,the FGMFs-based rectifying circuit(GRC)exhibits good flexibility and RF-to-DC efficiency of 53%at 2.1 GHz.Moreover,we further expand the application of FGMFs to a flexible wideband monopole rectenna and a 2.45 GHz wearable rectenna for harvesting wireless energy.The wideband rectenna at various bending conditions produces a maximum conversion efficiency of 52%,46%,and 44%at the 5th Generation(5G)2.1 GHz,Industrial Long-Term Evolution(LTE)2.3 GHz,and Scientific Medical(ISM)2.45 GHz,respectively.A 2.45 GHz GRC is optimized and integrated with an AMC-backed wearable antenna.The proposed 2.45 GHz wearable rectenna shows a maximum conversion efficiency of 55.7%.All the results indicate that the highly flexible graphene-film-based rectennas have great potential as a wireless power supplier for smart Internet of Things(loT)applications.

Manipulating the Macroscopic and Microscopic Morphology of Large-Area Gravure-Printed ZnO Films for High-Performance Flexible Organic Solar Cells

Gravure printing is a promising large-scale fabrication method for flexible organic solar cells(FOSCs)because it is compatible with two-dimension patternable roll-to-roll fabrication.However,the unsuitable rheological property of ZnO nanoinks resulted in unevenness and looseness of the gravure-printed ZnO interfacial layer.Here we propose a strategy to manipulate the macroscopic and microscopic of the gravure-printed ZnO films through using mixed solvent and poly(vinylpyrrolidone)(PVP)additive.The regulation of drying speed effectively manipulates the droplets fusion and leveling process and eliminates the printing ribbing structure in the macroscopic morphology.The additive of PVP effectively regulates the rheological property and improves the microscopic compactness of the films.Following this method,large-area ZnO∶PVP films(28×9 cm^(2))with excellent uniformity,compactness,conductivity,and bending durability were fabricated.The power conversion efficiencies of FOSCs with gravure-printed AgNWs and ZnO∶PVP films reached 14.34%and 17.07%for the 1 cm^(2)PM6:Y6 and PM6∶L8-BO flexible devices.The efficiency of 17.07%is the highest value to date for the 1 cm^(2)FOSCs.The use of mixed solvent and PVP addition also significantly enlarged the printing window of ZnO ink,ensuring high-quality printed thin films with thicknesses varying from 30 to 100 nm.

High-Performance All-Printed Flexible Micro-Supercapacitors with Hierarchical Encapsulation

Printed micro-supercapacitors(MSCs)have shown broad prospect in flexible and wearable electronics.Most of previous studies focused on printing the electrochemically active materials paying less attention to other key components like current collectors and electrolytes.This study presents an allprinting strategy to fabricate in-plane flexible and substrate-free MSCs with hierarchical encapsulation.This new type of“all-in-one”MSC is constructed by encapsulating the in-plane interdigital current collectors and electrodes within the polyvinyl-alcohol-based hydrogel electrolyte via sequential printing.The bottom electrolyte layer of this fully printed MSCs helps protect the device from the limitation of conventional substrate,showing excellent flexibility.The MSCs maintain a high capacitance retention of 96.84%even in a completely folded state.An optimal electrochemical performance can be achieved by providing ample and shorter transport paths for ions.The MSCs using commercial activated carbon as the active material are endowed with a high specific areal capacitance of 1892.90 mF cm^(-2)at a current density of 0.3 mA cm^(-2),and an outstanding volumetric energy density of 9.20 mWh cm^(-3)at a volumetric power density of 6.89 mW cm^(-3).For demonstration,a thermo-hygrometer is stably powered by five MSCs which are connected in series and wrapped onto a glass rod.This low-cost and versatile all-printing strategy is believed to diversify the application fields of MSCs with high capacitance and excellent flexibility.

New Method for Predicting the Motion Responses of A Flexible Joint Multi-Body Floating System to Irregular Waves

A new hybrid method of frequency domain and time domain is developed in this paper to predict the motion responses of a flexibly joint multi-body floating system to irregular waves. The main idea of the method is that the three-dimensional frequency method is used to obtain the hydrodynamic coefficients and the response equations are solved in time domain step by step. All the forces can be obtained at the same time. The motions and nonlinear mooring forces of a box type six-body floating system are predicted. A comparison of the theoretical method-based Solutions with experimental results has shown good agreement.

Oxygen functionalization-assisted anionic exchange toward unique construction of flower-like transition metal chalcogenide embedded carbon fabric for ultra-long life flexible energy storage and conversion

The metal-organic framework(MOF)derived Ni–Co–C–N composite alloys(NiCCZ)were“embedded”inside the carbon cloth(CC)strands as opposed to the popular idea of growing them upward to realize ultrastable energy storage and conversion application.The NiCCZ was then oxygen functionalized,facilitating the next step of stoichiometric sulfur anion diffusion during hydrothermal sulfurization,generating a flower-like metal hydroxysulfide structure(NiCCZOS)with strong partial implantation inside CC.Thus obtained NiCCZOS shows an excellent capacity when tested as a supercapacitor electrode in a three-electrode configuration.Moreover,when paired with the biomass-derived nitrogen-rich activated carbon,the asymmetric supercapacitor device shows almost 100%capacity retention even after 45,000 charge–discharge cycles with remarkable energy density(59.4 Wh kg^(-1)/263.8μWh cm^(–2))owing to a uniquely designed cathode.Furthermore,the same electrode performed as an excellent bifunctional water-splitting electrocatalyst with an overpotential of 271 mV for oxygen evolution reaction(OER)and 168.4 mV for hydrogen evolution reaction(HER)at 10 mA cm−2 current density along with 30 h of unhinged chronopotentiometric stability performance for both HER and OER.Hence,a unique metal chalcogenide composite electrode/substrate configuration has been proposed as a highly stable electrode material for flexible energy storage and conversion applications.

Gel-Based Triboelectric Nanogenerators for Flexible Sensing:Principles,Properties,and Applications

The rapid development of the Internet of Things and artificial intelligence technologies has increased the need for wearable,portable,and self-powered flexible sensing devices.Triboelectric nanogenerators(TENGs)based on gel materials(with excellent conductivity,mechanical tunability,environmental adaptability,and biocompatibility)are considered an advanced approach for developing a new generation of flexible sensors.This review comprehensively summarizes the recent advances in gel-based TENGs for flexible sensors,covering their principles,properties,and applications.Based on the development requirements for flexible sensors,the working mechanism of gel-based TENGs and the characteristic advantages of gels are introduced.Design strategies for the performance optimization of hydrogel-,organogel-,and aerogel-based TENGs are systematically summarized.In addition,the applications of gel-based TENGs in human motion sensing,tactile sensing,health monitoring,environmental monitoring,human-machine interaction,and other related fields are summarized.Finally,the challenges of gel-based TENGs for flexible sensing are discussed,and feasible strategies are proposed to guide future research.

Hierarchically Structured Nb_(2)O_5 Microflowers with Enhanced Capacity and Fast-Charging Capability for Flexible Planar Sodium Ion Micro-Supercapacitors

Planar Na ion micro-supercapacitors(NIMSCs) that offer both high energy density and power density are deemed to a promising class of miniaturized power sources for wearable and portable microelectron-ics. Nevertheless, the development of NIMSCs are hugely impeded by the low capacity and sluggish Na ion kinetics in the negative electrode.Herein, we demonstrate a novel carbon-coated Nb_(2)O_5 microflower with a hierarchical structure composed of vertically intercrossed and porous nanosheets, boosting Na ion storage performance. The unique structural merits, including uniform carbon coating, ultrathin nanosheets and abun-dant pores, endow the Nb_(2)O_5 microflower with highly reversible Na ion storage capacity of 245 mAh g^(-1) at 0.25 C and excellent rate capability.Benefiting from high capacity and fast charging of Nb_(2)O_5 microflower, the planar NIMSCs consisted of Nb_(2)O_5 negative electrode and activated car-bon positive electrode deliver high areal energy density of 60.7 μWh cm^(-2),considerable voltage window of 3.5 V and extraordinary cyclability. Therefore, this work exploits a structural design strategy towards electrode materials for application in NIMSCs, holding great promise for flexible microelectronics.

Ionic Liquid-Enhanced Assembly of Nanomaterials for Highly Stable Flexible Transparent Electrodes

The controlled assembly of nanomaterials has demon-strated significant potential in advancing technological devices.However,achieving highly efficient and low-loss assembly technique for nanomate-rials,enabling the creation of hierarchical structures with distinctive func-tionalities,remains a formidable challenge.Here,we present a method for nanomaterial assembly enhanced by ionic liquids,which enables the fabrication of highly stable,flexible,and transparent electrodes featuring an organized layered structure.The utilization of hydrophobic and non-volatile ionic liquids facilitates the production of stable interfaces with water,effectively preventing the sedimentation of 1D/2D nanomaterials assembled at the interface.Furthermore,the interfacially assembled nanomaterial monolayer exhibits an alternate self-climbing behavior,enabling layer-by-layer transfer and the formation of a well-ordered MXene-wrapped silver nanowire network film.The resulting composite film not only demonstrates exceptional photoelectric performance with a sheet resistance of 9.4Ωsq^(-1) and 93%transmittance,but also showcases remarkable environmental stability and mechanical flexibility.Particularly noteworthy is its application in transparent electromagnetic interference shielding materials and triboelectric nanogenerator devices.This research introduces an innovative approach to manufacture and tailor functional devices based on ordered nanomaterials.