最新刊期
期 1 ， 2016
- 摘要：Grouplet transform is a new directional wavelet. This wavelet can be transformed at any time and space,and adaptively change the basis according to image texture. Therefore Grouplet transform has a good ability of sparse representation.Here,Grouplet transform is introduced into the metal fracture images,and combined with the Kernel Principal Component Analysis（ KPCA）,a new recognition method of metal fracture images based on Grouplet-KPCA is proposed. At the same time,the proposed method is compared with the wavelet-KPCA recognition method. The experimental results show that the proposed method can overcome the information of finite directions only obtained by the wavelet-KPCA recognition method,and can have a satisfactory recognition rate. Compared with Grouplet entropy,Grouplet kurtosis is more sensitive to the texture change of metal fracture and suitable for feature extraction of metal fracture. Therefore the recognition method based on Grouplet kurtosis-KPCA have better recognition rate than the recognition method based on Grouplet entropy-KPCA.关键词：Grouplet transform;Kernel principal component analysis（KPCA）;Metal fracture image;Feature extraction;Pattern recognition
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发布时间：2022-09-22 - 摘要：For vertical vibration systems tend to ignore the influence of hydraulic screw down system in the rolling mill,two degrees of freedom hydraulic screw down vertical vibration system model was established based on viscous damping between the hydraulic cylinder and the frame,nonlinear stiffness between the rolling interface. By means of a multiple scales method,the existence and stability of periodic solutions in a first order approximation close to the main parametric resonance were investigated,and the frequency-response equation was provided. The impacts of nonlinear stiffness and viscous damping on the rolling mill vibration were analyzed,and the impacts of excitation frequency on non-linear vertical vibration were analyzed by the phase plane method,the Poincare mapping method and the maximum Lyapunov exponent. Analysis’ s results provide a reference for engineering to solve the vibration problem of hydraulic screw down system.关键词：Rolling mill;Hydraulic screw down;Parametric excitation;Vertical vibration;Main resonance;Chaos
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发布时间：2022-09-22 - 摘要：Due to the center deviation among wellhead,rotary table and crown block,the deep groove ball bearing of rotary control head（ RCH） is affected by large lateral load. In the meantime,deep groove ball bearing can produce a large amount of heat because of the effect of friction torque,which is easy to cause the failure of bearing on account of high temperature and reduce production safety performance on site of RCH. In order to optimize and timely replace the lubrication cooling medium,furthermore,to improve the service life of the deep groove ball bearing and the overall performance of RCH,this paper pays attention to the temperature change of deep groove ball bearing. Based on the laboratory test datas,grey neural network was applied to establish mathematic model for predicting the temperature of deep groove ball bearing,and compared with BP neural network. The results show that grey neural network has the advantages of high prediction precision,good stability and less sample data,which has important application value on the temperature prediction of deep groove ball bearing and the design of RCH’s cooling lubrication system.关键词：Rotary control head;Deep groove ball bearing;Grey neural network;Temperature prediction
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发布时间：2022-09-22 - 摘要：There is large number of joint in a machine tool structure. The performance of the whole machine tool structure is affected by these joints. In order to predict and evaluate the performance of machine tool structure,it is required to approach an experimental method to obtain the foundation characteristic parameters of joints. A new method to identify the damping parameters of joints is proposed based on the acceleration transfer function. The calculation of the stiffness matrix and mass matrix can be avoided by computing the real and imaginary parts of the acceleration transfer function. It is a simple and useful method to identify the damping of a joint. The method is verified through the foundation parameters experimental of joints.关键词：Joint parameter identification;Transfer function;Damping;Acceleration
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发布时间：2022-09-22 - 摘要：Strategy of Speed disturbance is used to stabilize an unstable periodic orbits which embedded in the chaotic attractor of chaos in nonlinear torsional vibration model of a planetary gear set. The small speed disturbance control strategy is used for the system that the differential equations are unknown and the allowance of speed disturbance is very small and the optimal parameter control method is used to calculate the speed disturbance in the control procedure. A new method called large parameter perturbation is used for the system that the differential equations are known and the allowance of speed disturbance is relatively big,and the speed is still selected as control parameter. Both the two method control the chaos of planetary gear set to periodic motion state successfully.关键词：Planetary gear set;Chaos control;Strategy of speed disturbance;The optimal parameter control method;Large parameter perturbation method
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发布时间：2022-09-22 - 摘要：Permanent magnet synchronous motor（ PMSM） having the following characteristics of high efficiency,high stability,long using life and simple maintenance is one of the important development directions in the motor field. The research on electromagnetic vibration is foundations of designing the low noising PMSM. The structure of PMSM is introduced. The models of air gap magnetic ux density,the radial electromagnet force and structural vibration are developed. The factors effecting electromagnetic vibration are theoretical analyzed,the frequencies of electromagnetic vibration are given. The simulation results show the PMSM produces severe vibration with frequency of 2,4 and 6 times fundamental frequency,when the number of slot near to 2,4,6 and 8 times the number of poles. These efforts provide references for designing different type of permanent magnet synchronous motor.关键词：Permanent magnet synchronous motor;Electromagnetic vibration;Magnetic field analyzing;Air gap magnetic ux density;Magnetic pressure waveform
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发布时间：2022-09-22 - 摘要：The theoretical model of double-layer vibration isolation system based on the icebox compressor was built through the four-point parameter method,and got the force transportation-rate pattern,found the finite element simulation model of double-layer vibration isolation,obtained the main mode of the system through mode analysis and the force transportation-rate through dynamic reaction analysis. The force transportation-rate results through theoretical model and finite simulation method and test were compared and analyzed,the results show,the natural frequencies obtained from the theoretical model and simulation model are basically same,the force transportation-rate has the same trend on the whole,the theoretical results and simulated results accord well with the test results in the low frequency between 0 to 150 Hz,when the frequency exceeds 150 Hz,there are some differences between theoretical results,simulation results and test results to some extent.关键词：Four-point parameter method;Double-layer vibration isolation;Force transportation-rate;Natural frequency;Finte element method
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发布时间：2022-09-22 - 摘要：A method for optimizing support vector machine（ SVM） parameters was proposed based on isometric feature mapping（ Isomap） and improved genetic algorithm（ IGA）,to solve the problem that parameters are difficult to choose in the process of gearbox fault diagnosis and recognition. Firstly Isomap was used for high-dimensional feature data of gearbox vibration signal under the automatic optimal neighborhood parameter value. Then optimized the castigation parameter and nucleus function parameter of SVM by improved genetic algorithm. Finally the recognition and classification of lower dimensional data were realized by SVM. The proposed method was applied to gearbox fault diagnosis. The result shows that the method has higher diagnosis accuracy,and it has better diagnosis effect compared with traditional SVM method.关键词：Isomap;Genetic algorithm;Support vector machine（SVM）;Gearbox;Fault diagnosis
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发布时间：2022-09-22 - 摘要：Based on remanence magnetic field of ferromagnetic materials,a finite element model for leaking magnetic field of broken wire of bridge cables was established. Using this model the magnetic field distribution of fracture surface of the wire and the air leak were analyzed,the leaking magnetic field strength was calculated. At the same time,a testing platform of broken wire of cables by using three-dimensional magnetoresistive sensor was build. Experimental results confirmed the existence of leakage magnetic field of broken wire and it can be detected. The leakage magnetic flux signal characteristics varies from different number and different locations of broken wire,which verify the correctness,effectiveness and feasibility of micro-magnetic detection methods.关键词：Micro-magnetic NDT;Bridge cable inspection;Analysis of leakage magnetic field;Magnetoresistive sensor
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发布时间：2022-09-22 - 摘要：Automotive Magneto-rheological Fluid Clutch（ MFC） is a new clutch that combines smart material,or Magnetorheological Fluid,and design of automobile clutch. Based on the Bingham model,the expressions of transmission torque for discshaped MFC were established. We design and process a sample machine to test the capability,stability of torque as well as performances of connection and separation. In addition,influences of magnetic saturation and residual magnetism to speeds of connection and separation also have been analyzed. The testing results indicate that the performance of MFC can meet the need of design and use.关键词：Magneto-rheological fluid;Vehicle;Clutch;Disc-shaped;Testing;Connection;Separation
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发布时间：2022-09-22 - 摘要：The mechanics behavior and failure characteristics of clinching joint specimens were investigated through the quasi-static tests and dynamic tests of single clinching joints under cross tension,lap shear and couch peel conditions,and also through the quasi-static tests with different loading angles（ 0 °,30 °,45 °,60 ° and 90 °）. The test results show that,the joint strength becomes greater while shear / tensile ratio increases,but the extensibility of clinching joints exhibits no obvious rule.Button separation happened in cross-tension tests; neck fracture in lap-shear tests; both two failure modes happened in couchpeel tests either separately or simultaneously. All clinching joints have strain rate effect under three typical conditions,i. e. the peak forces of all dynamic tests were higher than the corresponding ones of quasi-static tests.关键词：Clinching joint;Mechanical test;Mechanical performance;Failure mode
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发布时间：2022-09-22 - 摘要：Dynamic performance of gear system especially vibration was a typical nonlinear problem,while the vibration was closely related to the gear profile modification,the solving gear profile modification parameters was a nonlinear optimization problem. With a pair of spur gear as research object,armed with the kisssoftsoftware,by using orthogonal design method and genetic algorithm,aiming at reducing the fluctuation of vibration acceleration,optimum profile modifications of spur gears was designed. The research shows that orthogonal experimental method is combined with genetic algorithm for complex optimization problems,the fluctuation of vibration acceleration significantly reduced,and the damping effect is good in the paper.关键词：Gear;Gear-tooth modification parameter;Orthogonal design;Genetic algorithm;Vibration
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发布时间：2022-09-22 - 摘要：The test of the fatigue crack growth rate under five stress ratios（ R = 0. 1,0. 2,0. 3,0. 4 and 0. 5） is completed used the compact tensile specimen. The test data are processed by using incremental polynomial method and the expressions and curves of crack growth rate under different stress ratios are obtained. The effect of stress ratio on crack growth rate and two important parameters in Paris formula are analyzed. Moreover,the fatigue fractures under different stress ratios are analyzed,and discussed the mechanism of effect on crack propagation rate under different stress ratios.关键词：Paris formula;Incremental polynomial method;Stress ratio;Crack growth rate;Fractographs;Fatigue fracture
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发布时间：2022-09-22 - 摘要：The reliability of CNC lathe was allocated based on the failure information of CNC lathe. It used Edgeworth series method to expand the fault data into standard normal variable expansion to obtained the reliability. Tested with data fitting method,the distribution curve of Edgeworth was well resembled. To obtain subsystem reliabilities,the Edgeworth series method was introduced. Concentrating three kinds of influence factors from the perspective of fault information,the allocation model based on Date Envelopment Analysis（ DEA） was proposed. Based on failure information of CNC lathe,this method was considerably practical to improve the redistribution of the machine’s reliability.关键词：CNC lathe;Reliability allocation;Edgeworth series method;CCR model;Date Envelopment Analysis
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发布时间：2022-09-22 - 摘要：Optimization research on reliability of the catenary system and preventive maintenance strategy is the key to ensure the safe operation of the electrical railway. The choice of preventive maintenance strategy is more conducive to develop maintenance program of catenary system. Analyzing the catenary system based on fault tree analysis model and using different parameters’ Weibull distribution to describe the device failure probability of the various parts of the catenary system. The optimization function of preventive maintenance strategy on the catenary system based on reliability constraints is deduced.According to three years’ measured fault data of Changsha section,the parameters of Weibull distribution which describe the various parts of the catenary system is fitted,the maintenance costs of the catenary system in Changsha section were calculated according to the model of optimization on preventive maintenance strategy. Conclusions showed that: appropriately increasing maintenance times can reduce maintenance costs; high reliability requires will increase maintenance times and repair costs significantly. The maintenance strategy optimization model and the calculated results provide a useful reference for the Maintenance of the catenary system.关键词：Preventive maintenance strategy;The catenary system;Failure rate;Reliability
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发布时间：2022-09-22 - 摘要：Based on the rigid-flexible coupling multi-body system dynamics theory,built the rigid-flexible coupling model of shearer’s cutting part,researched the annular gear dynamic behavior during the process of meshing. According to the resistance of coal mining machine drum in the complex coal seam condition,generated the text files of the drum load based on Matlab programming. Simulated the model by Recur Dyn multi-body dynamics software,obtained the stress distribution of the shearer annular gear and contact force and contact moment with planetary gear,verified its correctness compared with the theoretical value. Through the fatigue life calculation,obtained the minimum fatigue cycles of annular gear tooth surface. Put forward improvement methods on the weak area and prolong its service life. Analyze its reliability when design could decrease the cost of research,provides a new method for the study of stress and fatigue life of shearer’s equipment in a wide range of rigid motion and small deformation of flexible component motion.关键词：Shearer;Multi-body system dynamics;Planetary gear;Contact force;Fatigue life
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发布时间：2022-09-22 - 摘要：Summed up six typical working conditions of the rail track replacement device. Its working load is calculated by three kinds of method. And the theoretical model of telescopic rail track replacement car for work equipment is established.Accelerating factor and inertia weight Improved PSO,and adding the chaos algorithm optimize five main parameters of hexagonal cross-section telescopic boom. The optimization results show,telescopic quality has reduced by 29. 6%; overall centroid position has down; counterweight with telescopic functionis smaller; the balance of front and rear axle bogie track replacement has achieved; In other railcars improved machine stability.关键词：Typical conditions;Theoretical model;Chaos algorithm;Parameters optimization
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发布时间：2022-09-22 - 摘要：Limit-point,elastic or elastoplastic,flexural or flexural-torsional buckling of spatial compression members are easy to happen in engineering structures,a simple unified buckling judgment method is need for engineering applications. This paper presented an axial stiffness judgment method,which was expressed under the Eulerian description and based on the definition of compression rod stabilization. The validity and applicability of the proposed method were verified by numerical analysis of a frame model. Then,the axial stiffness values of compression members of the frame were measured and calculated by the frame buckling experiment,and the experimental results were compared with the numerical results. Studies show that the buckling of local compression members may happen before the overall buckling of bars structures,and the axial stiffness judgment method can precisely judge the buckling of spatial compression members in engineering structures.关键词：patial compression members;Limit-point buckling;Judgment method;Axial stiffness
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发布时间：2022-09-22 - 摘要：In order to grasp the actually meshing of planar internal gear single-enveloping crown worm drive,the errors analysis is developed. Base on the gear meshing theory,the meshing geometry with errors of this worm drive is established,and the accurate 3D model is constructed. The tooth surface meshing status of this worm drive under the ideal conditions are studied,and the actually meshing status of this worm drive with the centre distance error and inclination angle error are studied. The results show that: there are five pairs tooth surface are contemporary meshing,and the contact lines are straight line,as well as the contact lines are average distributed and along the tooth height; the negative values of centre distance error and worm axial displacement error are better than the true values of those; the shaft angle error,the inclination angle error and the base circle radius error are seriously affect the actual meshing status of the planar internal gear single-enveloping crown worm drive.关键词：Worm drive;Crown worm;Errors;Actually meshing
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发布时间：2022-09-22 - 摘要：Fastened joint repair is a main repair method for composite structure with advantages of easy disassembling,high load transferring capacity. It is important to evaluate the residual strength in repair design process. In this paper,the tensile load bearing capacity of metal riveted repair laminates were evaluated by numerical simulation using progressive failure analysis method. Laminate was modeled using shell element whereas the fasteners were modeled by beam elements. MPC technique was adopt to simulate the constraint between fastener and hole. The USDFLD subroutine was used to degrade material stiffness by multi-lever manner while damage occurred. The failure analysis results including failure mode,failure load are in good agreement with test results. The errors of predicted failure loads are with 6%,which shows the proposed method is helpful to composite fastened joint repair design.关键词：Composite laminates;Fastened joint repair;Residual strength;Failure simulation
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发布时间：2022-09-22 - 摘要：Based on the software NX Nastran,the Cabin Cage finite element model was established,using beam,plate,solid and mass element properties. The structure’s max deformation and max stress were counted out,and an experiment was did to confirm the accuracy of the finite element model. Based on the simulation results,the authors optimized some part of the structure and did another simulation. The further results showed that the stiffness and strength of the optimized structure had been improved significantly. This modeling method with serious kinds of element properties can be widely applied in design and optimize of large-scale structures.关键词：Cage;NX Nastran;Finite element analysis;Structure optimization
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发布时间：2022-09-22 - 摘要：Applying the differential geometry theory and principle of coordinate transformation,the spatial curve parametric equations were derived. An geometric entity model of the anti-twist braided wire rope was established using the three-dimension software. The finite element model of the anti-twist braided wire rope can be acquired by appropriate meshing operation. The boundary conditions are set after loading the constraints and the mass force. and the numerical simulation of the strand stresses deformation was conducted. Then the distribution laws of strand stress distribution and axial deformation in axis dire- ction in its cross section were obtained. Friction coefficients were set as different parameters to obtain the influence law of friction coefficients on strand stresses deformation. The calculation results of strand with five different pitch were analyzed and the influence law of pitch on the strand was obtained.关键词：Anti-twist wire rope;Geometric modeling;Stress distribution;Deformation;Numerical simulation
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发布时间：2022-09-22 - 摘要：The problem of inaccurate results was presented based on irregular shell finite element analysis using traditional modeling methods,a finite element modeling method was presented based on simplified of transmission components. The paper introduced the bearings,gears and fasteners of simplified model method. For example,finite element analysis of automobile main reducer shell based on finite element software environment. Two finite element analysis models were established based on traditional method and simplify component method; Comparing simulation results of the two models found: stress distribution on the overall trend of automobile main reducer Shell was the same,but the value of the local area to install the bearing stress positions were quite different. Stress tests show in 100 N. m,200 N. m and 400 N. m of input torque main reducer: Simplified model approach closer to actual value of test results,verify the correctness and accuracy of the method.关键词：Driveline;Irregular shell;Simplified;Finite element model
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发布时间：2022-09-22 - 摘要：Rotary table is an important part of roadheader,it bears complex and changeable loads,so it is the key component of roadheader’s design. When the cutting head horizontal swing,the superposition between cutting resistance and cutting unit gravity is an important reason which caused the fracture of rotary table. Based on the theory of rock breaking of cutting head,found the optimal performance design parameters and simulated the load spectra of roadheader by using the roadheader’s aided design and load calculation software of cutting head. The rigid-flex coupled model of roadheader has been established and the weak areas of the rotary table has been found by dynamic simulation,then optimizing the structure of the rotary table,the force of the optimized rotary table is uniform,and it can work reliably and meet the requirements.关键词：Rotary table;Theory of rock breaking;Dynamic simulation;Structure optimize
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发布时间：2022-09-22 - 摘要：Load distribution characteristics of rolling bearing at high speed have important effects on the rotor system’s dynamic characteristics. In order to simulate the actual load distribution,the dynamic analysis model of rolling bearing is established by quasi-dynamic,simultaneously considering radial load,axial load,centrifugal force and gyroscopic moment acted on the rolling bearing,and study the rolling bearing load distribution under different radial load,axial load and speed conditions by MATLAB programming for solving nonlinear equations,the effect rules of contact angle and deformation are analyzed by program.关键词：Rolling bearing;Quasi-dynamic;Contact angle;Deformation
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发布时间：2022-09-22 - 摘要：Based on the geometric equations,physical equations,kinetic equations,and electrodynamics equations of thin shell,the thermal-magnetic-elastic coupling equations for a current-carrying cylindrical shell are established. Using the linearization method,the linear iterative equations on the thermal-magnetic-elastic problem are obtained and transformed into normal Cauchy type including eight basic unknown functions. The temperature field in the cylindrical shell and integral eigenvalues of the temperature field are derived after considering Joule‘s heat effect in an electromagnetic field and introducing the thermal equilibrium equation and generalized Ohm’s law. The results that the stresses,temperatures,and deformations in the current-carrying cantilever cylindrical shell change with variation of the electromagnetic parameters are discussed. It is proved that the stresses,strains,and temperatures in plates and shells can be controlled by changing the electromagnetic and mechanical parameters by considering a specific example.关键词：Current-carrying cantilever cylindrical shell;Coupling effect;Thermal-magnetic-elasticity;Displacement;Stress
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发布时间：2022-09-22 - 摘要：In order to reduce the temperature effects on compliant mechanisms,the comparative analysis of temperature effects on four kinds of typical flexure hinge with straight-beam,circular,elliptic and parabolic section is carried out,so that we can choose reasonablely the flexure hinge used to design compliant mechanisms. The flexure hinge is diviede into two variable cross-section beam elements,and the initial strain caused by temperature change is accounted into. The principle of minimum potential energy is applied to derive the thermal load vector and stiffness matrix of four kinds flexure hinge,and the mass matrix is obstained by employing Lagrange equation. And the mechanical model of the flexure hinges is obtained. The comparative analysis of the precision,thermal stress and thermal vibration of the compliant four-link mechanism is carried out based on the finite element model of the flexure hinge. The analysis results showed that the thermal errors of circular hinge is largest,and parabolic one,elliptic and straight-beam is smallest; The sequence of thermal stress from large to small is circular,elliptic,parabolic and straight-beam flexure hinge; The thermal vibration resonant frequency of the straight-beam hinge is minimum,the circular and elliptic one is second,parabolic is maximum,and it illustrated that the straight-beam hinge is more sussceptible to temperature changes. But the amplitude of the parabolic hinge at the resonant frequecy is maximum,and the thermal vibration is more larger.关键词：Flexure hinge;Fintite element method;Temperature effect;Comparative analysis
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发布时间：2022-09-22 - 摘要：Low cycle fatigue failure is the main failure form of disks. In order to find a more accurate and reliable method to predict disks’ low cycle fatigue life,a correction life prediction model that describes the relation between Walker equivalent strain parameter and fatigue life was proposed based on the formula of three-parameter power function. The low cycle fatigue experimental data of 1Cr11Ni2W2 Mo V,GH4133,TC4 and TC11 materials at different conditions was simulated by the correction life prediction model and found the fitting curves can well describe the relation between Walker equivalent strain and fatigue life,and the life forecasting points are all in the 2 scatter band. In addition,using different methods to predict its life of high pressure compressor disk I at 60℃ and compared them with the experimental result. The results show that the correction model has a higher prediction accuracy than the other three models,its prediction value is 1048 that is close to the experimental value 1340 and the relative error is only- 21. 8%,moreover,this correction model can consider the influence on fatigue life that brought by the mean stress‘s change and provide a reference method for aircraft engine disks’ low cycle fatigue life prediction.关键词：Low cycle fatigue（LCF）;Disks;Three-parameter power function;Walker equivalent strain;Life prediction
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发布时间：2022-09-22 - 摘要：In this study,a method is proposed to identify structural damages by the change of structural generalized flexibility. By adding known masses to the physical structure,measuring the lower modes of the mass-modified structure,and then using these new data as well as the original test information,structural damages can be detected using the generalized flexibility perturbation technique. The effectiveness of the proposed method is illustrated using simulated data on a plane truss structure. The results show that the proposed method can identify structural damages accurately only using the first modal parameters. The presented scheme may be useful for damage identification of large-scale structures.关键词：Damage identification;Added masses;Generalized flexibility;Modal parameter
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发布时间：2022-09-22 - 摘要：Traditional bogie frame fatigue design uses the amplitude loads,which is significantly not inconsistent with random excitation suffered on the frame in actual operation. This method often leads to excessive fatigue strength of the overall frame and the anti-fatigue design in local structure insufficient. Firstly,the inverse Fourier transform was used to transform the stochastic process between time domain and frequency domain,and the correctness and feasibility of load history which proposed is verified by comparative analysis. Then,based on the inverse Fourier transform method and cubic spline differential method,rail vertical irregularity and longitudinal irregularity in displacement,velocity and acceleration power spectrum were given,respectively. Finally,the multi-point and multi-axis random vibration analysis of the bogie frame was processed,the real operating conditions of the structure were simulated,and the weak fatigue position of the structure was predicted. The results shows that the fatigue life calculation of the frequency-domain can be good used to predict the vibration fatigue,and provide an effective method for anti-fatigue design of bogie frame.关键词：Bogie frame;Fatigue life;Frequency domain method;Multi-point multi-axis random vibration analysis
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发布时间：2022-09-22 - 摘要：Based on ANSYS,a finite element model of calculating stress intensity factor（ SIF） for 300 M steel M（ T）sample with different thickness was established and the numerical solutions of SIF for different thickness were compared. The aN curves were accordingly fitted through the SIF numerical solutions and the SIF analytical solutions of different thickness and the Paris formula. And the fitting curves were compared with the experimental data. The results show that the thickness effect influences the finite element numerical solutions of SIF considerably and for the analytical solutions of different thickness,the numerical solutions have certain thickness correction.关键词：ANSYS;Stress intensity factor;Thickness effect;Thickness correction
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发布时间：2022-09-22 - 摘要：To the interference fit surface of EMUs’ bearing-axle coupling system occurred fretting damage frequently,the solid model and finite element model of the CRH2 EMUs’ bearings-axle coupling system were established with considering the influence of load and interference. The statics behavior of bearing-axle system was studied by analyzing the stress distribution and deformation of matching surface under different routes or multiple interference. The results show that the maximum stress of the curving route is larger than the straight route under the same interference. The maximum stress and plastic deformation would become larger with the increasing of interference on the same route. While the interference was 0. 15 mm which exceeded the maximum allowable range,bearing inner race arose crack. The research can provide reference for the study on fretting problem of interference fit of EMUs’ bearings-axles system.关键词：Interference fit;Fretting;CRH2 EMUs;Stress;Statics behavior
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发布时间：2022-09-22 - 摘要：Put forward a kind of skin structure crane optimization design method based on reliability analysis. Considering the randomness of size parameters,material properties and wind load in the skin structure crane design,using Monte-Carlo method of Latin hypercube sampling（ LHS） technique to calculate the reliability of structure system. Through probabilistic sensitivity analysis to determine the optimal design variables,with the total quality of metal structural system of skin structure crane as the goal,to optimize the design by using the finite element analysis software ANSYS,relative to the initial design the quality of skin structure is reduced by 23. 8%,the overall reliability is used effectively,avoids the local reliability surplus,saves manufacturing cost.关键词：Skin structure;Monte-Carlo method;Reliability;Sensitivity Analysis;Optimized design
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发布时间：2022-09-22 - 摘要：The purpose is to design suitable loading test devices for small and medium-sized reducer manufacturing enterprises with the characteristics of low cost,energy saving and torque exerting dynamically. It designed the loading devices of"worm control and double planetary transmission"on the basis of the design and rationality analysis of the test bed of mechanical sealing scraper conveyor retarders. It set the parameters of the actual overload test for the simulation and carried out the dynamic simulation on the loading device and determined the performance relationship. It provides a new loading method of reducer test bed for the small and medium-sized manufacturing enterprises.关键词：Scraper conveyor;Reducer;Loading device;Dynamics simulation
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发布时间：2022-09-22 - 摘要：Slider is one of the main parts of a rocket projectile,which determines the stability and safety of a rocket launch. A slider structure design that satisfies the suspended-type launch was introduced in this research. Based on the theoretical analysis of offtrack speed and time,the slider structure was designed. By using numerical simulations,the strength of front slider under two different situations,ontrack and offtrack,was checked. The results show that the strength of slider meets the design requirement. The designed slider was applied to a rocket projectile flying test and the design feasibility was verified.关键词：Rocket projectile;Slider;Structure design;Strength analysis
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发布时间：2022-09-22 - 摘要：Based on the theory of random vibration,the dynamic response on tower crane under random seismic excitation was investigated. The input of earthquake ground motion is indicated by Duxiuli-Chenhouqun power spectral. The random seismic responses of structural ’s force and displacement were researched under five different earthquake model input with uniform earthquake excitations method. The analysis reveals that the force of tower crane increase significantly under vertical seismic excitation than X-direction,Z-direction excitation have the greatest influence in tower body bending moment; the primary reason of tower arm fracture is vertical seismic action,too large seismic wave cause tower body capsized easily.关键词：Tower crane;Seismic response;Random vibration;Uniform excitation
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发布时间：2022-09-22 - 摘要：Through the analysis of working condition of three-dimensional adjusting frame,I perform theoretical calculations and choose the main components of three-dimensional adjusting frame. And I make a overall design of the mechanical structure of three-dimensional adjusting frame from top to down by using the software of UG NX. Then under the circumstance of ANSYS Workbench I complete the static analysis and modal analysis of three-dimensional adjusting frame,and got the overall deformation under their own gravity and first six order natural frequency and vibration mode. The results show that this design of threedimensional adjusting frame has the high stiffness and dominant frequency is lower than vibration frequency of the source and can effectively avoid the vibration of source.关键词：Three-dimensional adjustment price;Mechanism design;Static analysis;Modal analysis
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发布时间：2022-09-22 - 摘要：During the lightweight process of automobile,the body structure strength cannot meet the design requirement,which leads to components failure. In this paper,strength analysis of van body-in-white was done under six kinds of working conditions: fully load,1g braking,0. 8g turning,150 mm right front wheel rising,150 mm left rear wheel rising,150 m both right front wheel and left rear wheelrising. Then the stress distribution of vehicle under various working conditions was got and the danger zones were confirmed. Finally,strain and stress tests under fully load were conducted to confirm the simulation results,which can help us with the structural design of van body-in-white.关键词：Van;FEM;Structural design;Body-in-white
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发布时间：2022-09-22
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