To address the problem of neglecting load uncertainties and structural deformation in conventional support reaction calculations for full-scale aircraft static tests,this paper proposes a novel approach based on modu-lar transfer learning for accurately predicting high-load support reactions.The proposed method introduces a modular transfer learning framework in which separate models are developed to account for loading uncertainties.A primary prediction model is first established using historical test data to extract general static testing characteristics.Subse-quently,a residual correction model trained with low-load data from the current test condition is integrated,enab-ling adaptation and correction of prediction errors specific to the present testing scenario.Additionally,to explicitly consider structural deformation effects,a binomial regression technique is employed to estimate loading-point coor-dinates at high-load levels,facilitating accurate determination of loading directions.By combining these coordinates with spatial force equilibrium equations,precise prediction of support reactions is achieved.The effectiveness and accuracy of the proposed method are validated through a full-scale static test case involving a representative verifica-tion aircraft.Comparative analyses demonstrate that,compared with traditional rigid-body assumptions,the devel-oped method significantly enhances the prediction accuracy for high-load stages,thereby providing robust theoretical and technical support for support reaction estimation in large-scale and complex testing environments.
To reduce the mass and manufacturing cost of phased array antennas while ensuring stable radiation per-formance under harsh operating conditions,this paper proposes a multi-objective surrogate optimization algorithm based on the Kriging model—MOAK.The algorithm integrates a feasible-region exploration criterion with a TCF-SMOTE criterion to form a hybrid infill strategy.The feasible-region exploration criterion enables effective identifica-tion of the global feasible space,after which the innovative TCF-SMOTE criterion is employed to construct a com-plete Pareto front,thereby achieving high-accuracy Pareto-optimal solution sets.Specifically,the TCF-SMOTE cri-terion suppresses extreme constraint violations in Kriging model construction through a truncated constraint function(TCF),mitigating model distortion near feasible-domain boundaries.In addition,the SMOTE algorithm is applied to generate synthetic sample points,increasing the number of Pareto solutions(PS)and improving the completeness of the Pareto front(PF).Comparative experiments on three standard benchmark functions demonstrate that the MOAK algorithm significantly outperforms conventional surrogate-model-based optimization al-gorithms,alleviating the problems of sparse PS distribution and incomplete PF characterization.When applied to the optimization design of the pre-skeleton of a phased array antenna,MOAK provides diverse solutions for balan-cing structural lightweighting,cost,and radiation performance,thereby meeting different design preference require-ments.In a representative optimized design,MOAK achieved a 35.4%reduction in mass,an 80.2%reduction in cost,and an 84.91%reduction in computation time,while maintaining stable radiation performance.
Studying the dynamic characteristics of the vehicle during the water-exit process through ice-breaking has significant scientific value and engineering significance for improving its performance and ensuring the safety of polar missions.Focusing on the dynamic characteristics of ice fragmentation and impact loads during the water-exit process of a vehicle breaking through ice,this paper establishes a numerical simulation method for the ice-vehicle-water coupling interaction based on the ALE algorithm and the penalty function contact algorithm.The dynamic characteristics under different launch velocities and dual-vehicle launch conditions are investigated,and the ice fragmentation characteristics and vehicle load characteristics during the water-exit process are obtained.The research results show that the water-exit process of the vehicle breaking through ice can be divided into three stages.The load on the vehicle mainly consists of fluid force and contact force,with the peak contact force reaching 2 600 kN and the peak fluid force reaching 1 400 kN.The fluid force on the dual-vehicle configuration is reduced by 50%compared with that on the single-vehicle configuration during ice-breaking.As the launch velocity increa-ses,the velocity decay rate of the vehicle gradually decreases.When the launch velocity is 50 m/s,the velocity de-cay rate is 5.98%.The research results can provide theoretical basis and technical support for underwater launch engineering of vehicles in polar environments.
Single-cell culture has long posed a significant challenge and remained a hot topic in biomedical engi-neering.To address the limitations in existing microfluidic single-cell chips,where cell culture space is constrained by the capture zones——impeding long-term cultivation.This study presents a capture-culture dual-zone integrated microfluidic chip,which integrates cell capture and culture functional region within a single unit.Through optimized chip layout design,the device achieves a microsphere capture rate of 91.93%and a cell capture rate of 60.1%.This study employs mouse fibroblast L929 cells(average diameter:10 μm)as the model system,establishing a hydro-dynamic flow model of cell suspension within the chip through theoretical calculations and computational simulations.To ensure cell viability,a microchannel width of 60 μm achieves optimal capture efficiency.To validate the chip performance,under conditions of a cell(or microsphere)input density of 1×105 cell/mL and a flow velocity of 300 μm/s,the cells exhibited stable post-entry conditions.With a microchannel width of 60 μm,the chip achieved both high capture efficiency and single-cell isolation rates,yielding a robust single-cell microflu-idic device with stable bonding.This chip demonstrates a simple structure and straightforward fabrication process,serving as a novel tool for single-cell analysis and research.
A light helicopter is widely used in low-altitude transportation.How to improve gear transmission effi-ciency and enhance the smoothness,durability and reliability of the traditional face gear transmission system are ur-gent problems to be solved.To carry out the weight reduction and dynamic characteristic analysis of the face gear body structure,the paper proposes a face gear body structural lightweight optimization design method that combines topological optimization and parametric optimization.The 3D model of the face gear was established with the finite element method.The solid isotropic material with penalization topological optimization and the sensitivity analysis of the face gear body structure were carried out to select the key design parameters.The multi-objective genetic algo-rithm was used to realize the multi-objective parametric optimization.The optimization results show that after topolo-gical optimization,the mass of the face gear body is reduced by 35.34%,that the maximum equivalent stress de-creases by 15.44%and that the maximum axial displacement of the face gear rim decreases by 29.19%.The trave-ling wave resonance analysis indicates that no-nodal diameter resonance points are within the working rotational speed range of the face gear body,significantly enhancing its strength and axial stiffness.
To further elucidate the adjustment mechanism of inlet guide vanes in axial compressors of aero-engines,this paper investigates a 1.5-stage high-load compressor using numerical simulation methods.This study comprehen-sively examines the influence law of various setting angles of in-let guide vanes at different corrected speeds on com-pressor performance.The results indicate that positive pre-swirl adjustment of the inlet guide vane significantly ex-tends the stable operating range of the compressor while improving pressure ratio and efficiency.By analyzing the pressure ratio,efficiency,and stability margin under different pre-swirl angles,an efficiency-optimized adjustment strategy was developed.This strategy enhances the stability margin of the compressor by 5.31%,6.33%,and 3.84%at 85%,75%,and 65%corrected speeds,respectively,demonstrating notable improvement.These findings provide a theoretical basis for optimizing inlet guide vane adjustment strategies in axial compressors.
Evidence modeling and fusion accuracy of multi-sensor information directly determines the target recogni-tion performance.As a classic framework for uncertain information reasoning and fusion,Dempster-Shafer evidence theory has been widely applied in multi-source information fusion.However,when there is a strong conflict between evidence bodies,the direct application of Dempster's combination rule often leads to counter-intuitive and even un-reliable fusion results.Although existing improved methods alleviate the conflict problem to a certain extent,they still have limitations such as slow convergence speed,insufficient ability to suppress interference from unreliable in-formation,and redundant network modeling.To address the above issues,this paper proposes an evidence modeling and fusion method based on complex networks.The method maps evidence bodies to network nodes and introduces a dual-weight complementary modeling mechanism of direct and indirect weights based on the interrelationships be-tween evidence.Specifically,the direct weights between network nodes are modeled by evidence distance to repre-sent the similarity between evidence bodies,and the indirect weights reflect the indirect support relationships of evi-dence bodies in the network structure through cosine similarity.By fusing and normalizing the two types of weights,the adaptive correction of the original evidence bodies is achieved,and then Dempster's combination rule is used to complete the fusion of conflicting uncertain information.Experimental results show that the proposed method exhibits faster convergence speed of target evidence,stronger interference suppression capability,and more effective high-conflict evidence resolution performance in the multi-evidence fusion process,demonstrating good stability and reli-ability.
The gas-filled accumulator is a supply system component used to suppress the longitudinal oscillation of liquid rockets.To predict the dynamic and static characteristics of the accumulator,and realize its overall design,a gas-filled accumulator partition model is proposed based on the lumped parameter method,which includes the over-heated zone,saturated zone,overcooled zone,two-phase critical zone and solid zone.Under the assumption of small pulsation,analytical formulas for accumulator impedance are derived through linearization of the partitioned model.Under the quasi-steady assumption,analytical formulas for the static characteristic parameters,including the temperature of the ullage and bulk liquid,the ullage pressure,and the flow rate inside the overflow pipe,varying with accumulator inlet pressure,are derived in time domain,and the dimensionless parameters characterizing the accumulator's time-domain working characteristics are given.The ullage volume control capability of the gas-filled accumulator is studied,and the calculation method of the accumulator's start-up time,pressure change rate and emptying time was given.Based on the characteristic analysis,the design method and design process of the gas-filled accumulator are proposed,and a design case is given.This gas-filled accumulator solution design method can provide a reference for engineering design.
RISC-V's openness and modularity have accelerated adoption in high-performance processors,yet deep microarchitectural optimizations such as speculative execution and advanced prediction expose designs to Spectre-class transient execution attacks.This paper presents a design-stage security verification framework that integrates gate-level information flow tracking(GLIFT)with formal verification to proactively detect Spectre vulnerabilities in RISC-V processors.From synthesized RTL netlists(via Yosys),this paper automatically derive GLIFT models that track bit-precise confidentiality tags across logic,and this paper formalize three generic,Spectre-oriented proper-ties:enforcing permission checks for speculative memory accesses,constraining speculative propagation of microar-chitectural state(e.g.,caches and TLB),and guaranteeing post-misspeculation recovery consistency.These prop-erties are instantiated as system verilog assertions within the load-store unit and data cache and verified using questa formal with exhaustive state exploration.On SonicBOOM and Xuantie-910,the framework uncovers violations of all three properties,showing that speculative loads can bypass authorization,taint cache state during speculation,and leave residual effects that are not fully rolled back.Guided by formal counterexamples,this paper implement practi-cal exploits to validate impact:a port-contention timing channel on SonicBOOM and a Flush+Reload cache channel on Xuantie-910,and we realize eight Spectre variants(PHT,BTB,RSB,SSB)that successfully recover secrets with quantifiable leakage.Empirical results indicate higher throughput for variants requiring limited predictor mis-training,while cache-based channels entail broader probing than contention channels but remain reliable with cali-brated thresholds.The proposed approach bridges ISA intent and concrete microarchitectural effects,offering reus-able properties,automated GLIFT modeling,and a closed loop from verification to exploit validation,thereby infor-ming principled,proactive hardening of future RISC-V microarchitectures.
To enhance the load identification capability and overload resistance of the silicon-based MEMS setback safety device,a silicon-based MEMS setback arming device research is carried out based on the parallel-axis ammu-nition fuze.Firstly,based on the spring-mass block system theory,the displacement response of the setback safety device was analyzed.A Machette Hammer platform and a visualization test platform were established.Three typical direction impacts were tested on the setback safety device prototype to determine the lack of overload resistance.An improved setback safety device is proposed by introducing a fixed anchor point to constrain the lateral displacement of the mass.A comparative analysis of displacement response and stress distribution in the tooth mechanism between the original and improved devices was conducted by finite element simulation.The results demonstrate that the fixed anchor point configuration effectively enhances device performance.Finally,the enhanced prototype was fabricated using the deep reactive ion etching(DRIE)process,followed by testing for validation.Test results demonstrate sig-nificantly enhanced overload resistance in the modified device:Withstood multiple high-intensity shocks along the setback direction before function failure,while exhibiting no significant damage under lateral and reverse setback direction impacts.The results of this paper can provide a reference for the failure analysis and optimization of similar silicon-based MEMS setback safety devices.
The electrostatic chuck is a semiconductor process equipment that uses electrostatic adsorption force to attach a wafer to a surface and controls the surface temperature of the wafer through thermal conduction as the main temperature control method.It plays a key role in current integrated circuit equipment.The uniformity of tempera-ture(temperature difference)directly affects the quality of wafer film formation and is one of the crucial indicators.This study focuses on the factors affecting heat transfer in electrostatic chucks under high-temperature CVD process environment.Firstly,a thermal conduction model between CVD chamber environment and electrostatic chuck is es-tablished using ANSYS Workbench;Then,the influence of different electrostatic chuck structures and engineering errors on the surface temperature uniformity of electrostatic chucks under CVD process environment is analyzed;Fi-nally,experiments also verified the simulation results of one type of electrostatic chuck through CVD chamber.Based on the above analysis,the results indicate that for this type of electrostatic chuck,the contact structure be-tween the disc body and the shaft,as well as the distribution of heating wires,have a significant impact on the tem-perature field distribution.The inclination of the heating wire has almost no effect on the temperature field distribu-tion,The thermal conductivity of the shaft,the thickness of the shaft wall,and the size of the electrostatic chuck have an impact on the local temperature field distribution.The research content of this article has important guiding significance for the improvement of heat transfer theory of electrostatic chucks and the subsequent design optimiza-tion of electrostatic chucks.
In order to grasp the vibration characteristics of a lattice-structured air rudder made by additive manufac-turing,this paper carried out its multi-scale simulation and verification tests.Firstly,the design and additive manu-facturing of the air rudder with the body-centered cubic lattice structure are conducted with the selective laser melt-ing method.Then,the repeated unit cell(RUC)of the lattice structure is extracted and its periodic boundary condi-tions are established.On this basis,the mesoscopic stress distribution of the RUC under different loading conditions and the macroscopic equivalent mechanical performance parameters of the lattice structure are obtained with the multi-scale simulation.The results reveal that the body-centered cubic lattice structure is orthotropic macroscopical-ly.Finally,the natural frequency and mode shape of the air rudder are calculated with the method proposed in this paper.The calculation results show that the simulation results are in good agreement with the verification test re-sults,with the relative errors of the first three orders of natural frequency being less than 5.0%.
With the rapid development of computer technology,airborne operating systems face increasingly complex real-time task challenges.Multi-core multi-partition operating systems have emerged as one of the effective solutions to address these issues.In response to the problem of difficulty in manually configuring scheduling tables for airborne multi-partition operating systems,this paper comprehensively considers factors such as process perio-dicity,worst-case execution time,deadlines,priorities,partition attributes,and mutual interruption relationships between processes.By integrating optimization theory,the paper conducts a quantitative analysis and modeling of the schedulability of multi-partition operating systems.A two-level optimization scheduling model is established to allocate optimal start times and runtime lengths for each partition,thereby achieving automated scheduling table generation.To solve this model,the structural characteristics of optimization problems are leveraged for decoupling analysis,and efficient iterative solution algorithms are designed by combining the Lagrange multiplier method and alternating direction method.Testing was conducted on the self-generating and optimizing scheduling algorithm.Re-sults demonstrated that the algorithm could intelligently generate optimal schedules for each section,determine schedulability,provide modification suggestions for unschedulable issues,and effectively reduce operational risks during actual flight operations.
In the design and failure analysis of a complex multi-clamp piping system in an aero-engine,it is diffi-cult to determine the influence of layout dimension on its structural dynamic characteristics and to rapidly identify its key layout parameters,leading to high blindness and low efficiency.Based on the pipe layout method for a com-plex piping system,this study proposes a clamp position parameterization method to enable the simultaneous model-ing and collaborative optimization of various pipe shapes and clamp layouts.Experiments are conducted to validate the method before and after optimization.First,the inter-point parameterized line segment interpolation method is adopted to define clamp positions,thus allowing the simultaneous transformation of various pipe shapes and clamp positions.Second,the original feasibility problem is transformed into a multi-objective optimization one suitable for dynamic structural analysis.Numerical instances validate the feasibility of this method,with the piping system's dy-namic performances significantly improved.Finally,the Spearman correlation coefficient is employed to identify the local sensitivity of each parameter.The hypercube sampling Monte Carlo method is used to convert raw optimization data into statistically significant engineering applicable intervals,realizing the engineering application of the colla-borative optimization method.
In complex environments,multi-UAV cooperative encirclement tasks often face critical challenges such as low intruder trajectory prediction accuracy,excessive system energy consumption during task allocation,and in-sufficient obstacle avoidance capability under dynamic conditions.These issues severely limit the efficiency and reli-ability of encirclement operations.To address these problems,a two-stage cooperative encirclement framework con-sisting of a gathering phase and a guidance phase is proposed in this paper.In the gathering phase,an interpolation and error-correction polynomial fitting(IEC-PF)method is designed to achieve early interception and significantly improve the accuracy of intruder trajectory prediction.For the task allocation of capture points,an iterative convex optimization-based allocation strategy is developed to minimize total system energy consumption while strictly satisfy-ing the final capture formation constraints.In the guidance phase,UAVs construct an optimal encircling formation based on the assigned capture points.Within the generated obstacle-free convex regions,a nonlinear optimization method is used to compute optimal global paths and formation configuration parameters.An affine formation control strategy based on stress matrices is further introduced to ensure formation stability and reconfiguration during path tracking.Additionally,a deep reinforcement learning(DRL)-based local obstacle avoidance mechanism is integrated to enhance the system's real-time responsiveness to dynamic obstacles.Simulation results demonstrate that the proposed framework substantially improves obstacle avoidance performance in complex environments and enables reliable multi-UAV cooperative capture of intruding targets,as well as guiding them to designated areas.
In complex battlefield environments,regarding the issues of weak anti-jamming capability,poor environ-mental adaptability,and resultant performance imbalance in radar waveforms designed based on single criterion,a radar waveform design method under game conditions that combines multiple criteria is proposed.Firstly,a game model between radar and jammer is formulated.Then,the signal-to-interference-plus-noise ratio(SINR),mutual information(MI)and minimum mean square error(MMSE)are integrated through weighted fusion.Based on this fusion function,corresponding waveform strategies for radar and jamming are designed respectively.Next,the maxi-mum marginal reallocation(MMR)algorithm is used to solve the game model.After multiple iterations,the game model converges,and the optimal radar and jamming waveforms are finally obtained.Simulation experiments show that,compared with the game model based on a single criterion,the proposed method increases the signal-to inter-ference-plus-noise ratio by 5.42%and the detection probability of the radar by 3.99%.This design improves the radar's detection performance and detection and recognition performance,verifying the effectiveness of the proposed method.
In view of the backlash nonlinearity in the stabilizing-tracking system for self-propelled anti-aircraft gun,a backstepping control design method based on full-order terminal sliding-mode is proposed by considering the structural characteristics of the system and the dynamic load disturbance caused by the motion.The position loop signal of the system is unified in the geodetic coordinate system,the position feedback is calculated by using the equivalent closed-loop method,and the state space model of the stable tracking system with backlash is constructed with the approximate dead time function of backlash nonlinearity.Aiming at the problem that it is difficult to observe the disturbance torque at the load side,a finite time disturbance observer is designed to estimate it quickly and ac-curately with load acceleration.Based on the backstepping control theory and the chattering free full-order terminal sliding-mode method,a global backstepping controller is designed to make the error converge to the field near zero in finite time,and the uniform ultimate boundedness of the system is proved by Lyapunov method.The simulation results show that compared with PID control,the proposed method can effectively compensate the backlash nonli-nearity,significantly weaken the chattering phenomenon,and has higher pointing accuracy in stabilizing conditions.
To investigate the heat release characteristics of methane/air lean premixed bluff-body flames, this study employs experimental methods based on CH* chemiluminescence to examine the effects of equivalence ratio, inlet flow rate, and acoustic excitation with varying frequencies and amplitudes on flame oscillation behavior and heat release dynamics. Experimental results reveal four typical flame oscillation modes influenced by the equivalence ratio: local extinction oscillation, asymmetric structure oscillation, small-scale symmetric structure oscillation, and stable combustion. The heat release intensity increases approximately linearly with the equivalence ratio. For BVK (von Kármán vortex shedding) oscillating flames, the fluctuation in heat release rate initially increases and then decreases along the axial direction, peaking around x/d=5.5. In contrast, for small-scale symmetric oscillating flames, the heat release rate fluctuation shows a nearly linear increase with x/d. The influence of acoustic excitation on the flame's heat release behavior was also investigated. It was found that with increasing excitation amplitude, BVK-type oscillations gradually transition into large-scale symmetric structure oscillations. Overall, the amplitude of heat release rate fluctuations increases with the acoustic excitation amplitude; a similar trend is observed with respect to frequency. Under an excitation of 35 Hz and 1.0 V, the fluctuation amplitude of the heat release rate approaches 0.6.
Due to their large fuselage and complex landing gear configuration,multi-strut aircraft faces significant challenges in steering control and stability during ground maneuvers.These factors directly impact flight safety and airport operational efficiency.This study focuses on the AN124 aircraft and develops a mathematical model for ground turning behavior that incorporates the steering dynamics of a multi-strut landing gear system,based on fun-damental principles of dynamics.Using this model,the influence of various main gear deflection strategies on turn-ing performance is thoroughly analyzed,with particular attention to turning radius,nose gear steering torque,and tire sideslip.Three steering configurations are examined:deflection of the front main struts alone,deflection of the rear main struts alone,and simultaneous deflection of both front and rear main struts.A comparative analysis is con-ducted to evaluate the impact of each configuration on key performance metrics.Results show that simultaneous de-flection of the front and rear main struts offers the most significant benefits.It not only reduces the sideslip coeffi-cient of the nose wheel but also substantially decreases the aircraft's turning radius.These findings suggest that the coordinated operation of front and rear main struts should be considered in the design of multi-strut landing gear sys-tems to optimize turning performance.This study provides a theoretical basis for the design and optimization of land-ing gear systems in multi-strut aircraft.It contributes to improving turning performance,reducing maneuvering risks,and enhancing airport operational efficiency.
To address the issues that the Kriging surrogate model using the learning function as the convergence cri-terion cannot reflect the accuracy of predicted failure probability directly and accurately and incur high computation-al cost in modeling,a reliability analysis method based on Indicator Error Controlled Kriging(IEC Kriging)is pro-posed in this paper.With Kriging as the basic model,IEC Kriging establishes a sequential transmission relationship among sample information,performance functions,and failure probability.It analyzes the error of predicted failure probability based on the probability of indicator sign misclassification by the Kriging model at each sample point,while considering the corrective effect of candidate sample points on prediction accuracy.A dynamic sample selec-tion strategy is designed with the upper bound of the overall sample indicator error as the criterion,and the sample point with the highest corrective effect is incorporated into the training set to optimize the surrogate model,ensuring the accuracy of prediction results while improving the efficiency of building the surrogate model.The proposed meth-od is applied to the wear reliability analysis of spherical plain bearings in an aircraft high-lift device as a case study.Compared with Kriging methods using the EGO learning function and U learning function,the IEC Kriging demon-strates higher computational efficiency for reliability estimation,which can provide a theoretical method reference for mechanism reliability analysis.
