最新刊期
期 6 ， 2016
- 摘要：A nonlinear random vibration model of a current carrying thin rectangular plate simply supported at each edge was established when the plate was applied mechanical load in a magnetic field. The model was proposed based on the theories of plates and shells and the magnetic elastic mechanics. It was simplified as a nonlinear dynamics differential equation by using Galerkin variation method. Then the equation was equivalent to be a one-dimensional It stochastic differential equation by applying the stochastic average theory of a quasi non-integrable Hamilton system. The local stochastic stability of the system was judged using the maximum Lyapunov index. Its global stability of the system was also judged using the singular boundary theory.Finally the influences of the system parameters on the stochastic Hopf bifurcation were researched through the steady probability density function. The numerical simulation results were shown in the paper.关键词：Thin rectangular plate;Magneto-elasticity;Stochastic stability;Stochastic Hopf bifurcation
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发布时间：2022-09-22 - 摘要：Regarded as one of the major faults,the screw looseness fault in the connection between piston rod and crosshead was studied. To simulate the thread looseness failure,a multi-body dynamic model of the reciprocating compressor motion was created. It draws a conclusion that the change trends of the average settlement value and the peak-peak value can reflect the extent of thread loosening failure. Compared with the actual failure cases,the dynamic model is proved to be reasonable.关键词：Thread Looseness Fault;Fault mechanism;Multi-body dynamics;Reciprocating compressor
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发布时间：2022-09-22 - 摘要：Scraper conveyor is always working in complex and poor working environment. It will cause the longitudinal vibration of chains when the scraper group goes on material dragged by the chains,and the fault of seizing the chains caused by a sudden increase in material,foreign body stuck or other factors. Discrete the chain transmission system and establish the system dynamics model of the chain based on Kelvin-Vogit model through the finite element method. Determine the stiffness coefficient of the scraper chain combined with the theoretical calculation and actual measurement data. Carry out the numerical simulation on the fault condition of seizing the chains through the numerical simulation software. Obtain the speed change and tension distribution rules of the chain on the different seizing position. Finally,it is found that the experiment data and the simulation results are basically consistent compared experiment data with simulation results.关键词：Scraper conveyor;Round link chain;Dynamics;Kelvin-Vogit;Failure load
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发布时间：2022-09-22 - 摘要：The key of the degenerate state recognition of roller bearing is feature extraction and pattern recognition. Local characteristic-scale decomposition（ LCD） is a new time-frequency analysis method,which is very suitably applied to the feature extraction of roller bearing vibration signal. Since variable predictive model based class discriminate（ VPMCD） is a pattern recognition method in which the relationship between the feature values is adopted,it can be applied to the he degenerate state recognition of roller bearing. In this paper,LCD,VPMCD and Gaussain mixture model（ GMM） are combined. Furthermore,the degenerate state recognition method of rolling bearings based on LCD and GMM-VPMCD hybrid model is proposed. Firstly,the whole life data of rolling bearing is decomposed by LCD method and the feature values of the components are extracted; then the feature values are clustered in time domain by using GMM and the whole life data is divided into some degenerate states in time domain; finally,the VPMCD model is constructed and applied to the degenerate state recognition of roller bearing. The experiment results show that the GMM-VPMCD hybrid model based on LCD can be effectively applied to the degenerate state recognition of rolling bearing.关键词：Local characteristic-scale Decomposition;Gaussain mixture model;VPMCD;Roller bearing;Degenerate state recognition
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发布时间：2022-09-22 - 摘要：Aiming at the impact feature in fault signals of the rolling bearings,The improved algorithm diagnosis method EEMD-RA-KU was proposed to capture the impact feature. Firstly,Fault signals were decomposed into a series of intrinsic mode functions（ IMFs） with ensemble empirical mode decomposition（ EEMD）. Secondly,The IMFs were selected to reconstruct signals based on relative analysis（ RA） and kurtosis（ KU）. Thirdly,The reconstructed signals were filtered by the filter that the parameters were determined with the spectral kurtosis. Finally,The fault can be diagnosed by comparing the frequency of the envelope spectrum with the fault characteristic frequency of the bearing. The result shows that the fault feature information of the signal can be extracted accurately when there was a lot of background noise.关键词：Bearing fault;EEMD;Correlation coefficient;Kurtosis;Fault diagnosis
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发布时间：2022-09-22 - 摘要：Regarding the new type of centrifugal spinning electric spindle as the research object,the method of rigid-flexible coupling was used to build the dynamic model of electric spindle; On the basis of modern computer simulation technology,the system vibration characteristic analysis was finished by using the combining simulated technique of Adams and Ansys,get the forced vibration amplitude frequency,phase frequency characteristic,then the electric spindle structure was improved,and software verification on the improvement. Experimental results shows: the structure improvement practical and effective.关键词：Electric spindle spinning;Rigid-flexible coupling;ADAMS;ANSYS;Vibration characteristics;Structure improvement
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发布时间：2022-09-22 - 摘要：Ladder type disc acoustic radiator is widely used in high power ultrasonic field. The frequency equation of stepped thickness disk in free boundary condition are derived based on Mindlin theory from the acoustic point of application and The frequency equation was numerically solved,At the same time,the effects of geometric parameters on the frequency is analyzed. The results show that when the other parameters are constant,the frequency increases with the increase of the disk and the base ring thickness,and decreases with the diameter increases,increases with the increasing diameter. The test results of the calculated frequencies and finite element simulation and experiment is consistent with the basic. Design of bending vibration radiator the conclusion of the thick disc provides the theory reference and the frequency of debugging basis.关键词：Mindlin theory;Thick disc ladder;Frequency equation;Bending vibration
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发布时间：2022-09-22 - 摘要：The down-ground oscillatory focus has dynamic effects on the ground,it is important to study these responses for earthquake disaster reduction,shockproof,inversion of the oscillatory focus and so on. In this paper,the dynamic response problem of the out-of-plane harmonic circular oscillatory focus in the half-space was studied,at first,imaginary focus was used to give the displacement wave functions which can satisfy the stress-free boundary of the half-space,and the stress conditions on the boundary of the circular oscillatory focus was utilized to obtain the non-linear equation of the unknown coefficients,and the Graf addition formula and Fourier series expansion were used to obtain an infinite linear equations,and was solved with the finite truncation method with enough computation precision,at last,the displacement and the stress in the media can be obtained. The variations of the ground displacement and the tangential shearing stress around the boundary of the circular oscillatory focus were discussed by a given example,and the results showed the effectiveness.关键词：Circular oscillatory focus under ground;Wave function expansion;Ground displacement amplitude;Tangential shearing stress amplitude
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发布时间：2022-09-22 - 摘要：Reduce the work wear and prolong the service life of rolling bearings is crucial problem in industrial production.Sums up the basic types of rolling bearing and wear problem,the research of rolling bearing wear process at home and abroad,at present,the experimental study of rolling bearing wear,numerical simulation method,system engineering are introduced in the failure of the rolling bearing analysis method and the method of repair is commonly used in the actual production and the development trend of rolling bearing and wear problems and several aspects of the need to strengthen research were also discussed.关键词：Rolling bearing;Wear and tear;The simulation;The failure analysis of rolling bearing;Repair
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发布时间：2022-09-22 - 摘要：The bars under tension and compression loadings widely exist in the structural engineering applications,which are the important loaded elements. This is because of the existence of all kinds of installed errors,the bars under tension and compression loadings are sometimes under eccentric tension and compression,Therefore,the dynamic responses of applied loading should be studied in order to ensure safety designs. In this paper,the dynamic loading responses of the straight bar with a constant cross-section and under loading of end axial eccentric harmonic tension and compression loads were studied,the little deformation hypothesis and the principle of linear superposition were used to divide the problem into two sub-problems,one is the axial tension and compression loading problem; another is the bending problem. The variations of the axial deformation and planar deflection with different disturbance frequencies were given,which is the basis of further dynamic designs. The research ideas together with methods of separation of variables and Fourier integration transformation technology can be employed to investigate the dynamic loading responses of the bars which are subjected to any eccentric axial load and distribution along the axial load.关键词：Bars;Axial cyclic loading;Bending loading;Dynamic responses;Safety design
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发布时间：2022-09-22 - 摘要：In the present paper,the relevant provision in the ASME Code Case about"Applicability of the ASME exemption curve for Chinese pressure vessel steel Q345R"has been analyzed by using failure assessment procedure on the basis of true material testing data. For the normalized Q345 R investigated in this paper,the results indicated that both Charpy impact toughness and fracture toughness at low temperature are better than the requirements in ASME Code,the provision in ASME Code classifying Q345 R in Exemption curve A excessively underestimated the toughness of the material.关键词：Exemption Curves;Failure Assessment;Minimum Design Metal Temperature;Q345R
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发布时间：2022-09-22 - 摘要：The pre-tension force of a multi-bolted structure under pure tightening torque is studied by experimental methods. Firstly,Experiment for single bolted structure is implemented,whose pretension force is obtained by strain gauge method. It shows that this pretension force measurement method is reasonable by comparing the experimental results and the theoretical results. On this basis,the experiment for multi-bolted structure is operated. The results shows that its pretension force is lower than the single bolted structure,and its value is relating to the pretension state of the bolt. When the pretension state is stable,its pretension force is about 0. 6 times of the single bolted.关键词：Threaded bolt;Pre-tension force;Tightening torque;Torque coefficient
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发布时间：2022-09-22 - 摘要：Coal is the important basic energy in China,however due to the problems of conveyor belt running deviation and avultion caused by freezing adhesive turnabout roller surface,it seriously restricts with coal mine safe and efficient production in cold regions during winter and brings huge economic losses to the company,although existing solutions have a certain ease of coal freezing adhesion but can not fundamentally solve the problem. Through the freezing adhesive strength test device designed by ourselves,under conditions of- 25℃ temperature and 3h freezing time,freezing adhesive characteristic of four different materials with moisture content 40% of the coal slime were tested. Experimental studies have found that with the decrease of material waterlubricating coefficient of kinetic friction coal normal and tangential freezing adhesive strength decrease,it shows a certain linear relation,the results indicate that improving the water-lubricating performance can reduce the freezing adhesive strength,the discovery has important guiding significance to the selection and preparation of anti-freezing adhesive coating in engineering field,it deserves further explore and study.关键词：Coal;Freezing adhesion;Water lubrication;Kinetic friction;Coating
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发布时间：2022-09-22 - 摘要：Based on the dependence of fatigue crack growth（ FCG） threshold on stress ratio,a low-load-truncation method for FCG tests is proposed. The effects of FCG property,stress amplitude and stress ratio are considered by this method. FCG tests using middle tension（ M（ T）） specimens under a flight-by-flight spectrum and two truncated spectra were conducted. The difference between FCG lives under truncated spectra and those under baseline spectrum is less than 26%,but the test duration were shorten by 78% maximum. The test results indicate that the proposed low-load-truncation method can shorten FCG test period effectively without changing the failure mode or changing the FCG life irrationally.关键词：Crack growth;Load spectrum;Low-load-truncation;Threshold;M（T） specimen
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发布时间：2022-09-22 - 摘要：In order to improve the drilling efficiency and reduce the weight of the anchor recycling equipment,it took spiral drill pipe of the anchor recycling equipment as the research object,by selecting the inner and outer diameter of the drill pipe,blade thickness,pitch,helix angle,speed,blade number and blade height as the optimizing parameters. It chosen the highest efficiency in transport,the lightest in weight and the highest rate in secondary crushing as the ideal goal of the drill pipe optimization,the result indicates that the drilling efficiency is increased by 31. 4%,the weight is reduced by 12. 7% and the secondary crushing rate is increased by 48. 7% based on particle swarm optimization. The efficiency of the recovering has been improved,and the wear-resisting degree and intensity of the spiral pipe have been enhanced.关键词：Anchor recycling equipment;Spiral drill pipe;Particle swarm optimization algorithm;Structure optimization;MATLAB
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发布时间：2022-09-22 - 摘要：Considering the current temperature compensation method is used to establish the temperature compensation model using intelligent algorithm,and use swarm intelligent optimization algorithm to optimize and improve the compensation precision,has good compensation effect for nonlinear sensor temperature drift,but for the low efficiency of this method has good linearity,and the use of linear least squares fitting method the routine can get better compensation effect,so this will be the least squares fitting method and RBF neural network model integration,a model of temperature compensation of pressure sensor,using ant colony algorithm to optimize the conventional RBF neural network,improve the performance of compensation model. Through the MPX53 pressure piezoresistive pressure sensors were studied. The results showed that after using the temperature compensation method,sensor at various temperatures is basically the same temperature,with the use of the whole ant colony optimization RBF neural network method of temperature compensation effect is similar,but the intermediate temperature region due to the linear fitting method,the efficiency of the whole temperature compensation improved.关键词：Temperature compensation;Pressure sensor;RBF neural network;Ant colony algorithm
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发布时间：2022-09-22 - 摘要：Aerodynamic heat often plays a crucial role in the structural performance of some typical projectiles. Based on the structure performance constraints,the present paper aimed at developing a structural optimal design method to reduce the weight of typical projectiles under thermal-mechanical coupling conditions. By virtue of integrating ANSYS into ISIGHT optimization platform,and using APDL parametric modeling technology of ANSYS as well as thermal-mechanical coupling load analysis technology,the simulation model of the structure of typical projectiles was established. Results of the numerical example show that the typical projectile structures may have a 19. 8% reduction in weight with the requirements of strength and rigidity satisfied in a limit value. The rationality of the model and the validity of the method were verified by effective loss in weight. The present work can also provides insight into model establishment and optimal design of typical projectile structures.关键词：Projectile structures;Optimal design;Thermal-mechanical coupling;ISIGHT
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发布时间：2022-09-22 - 摘要：The deformation modes and energy absorption properties of honeycombs with a negative Poisson’s ratio under inplane dynamic crushing were studied by means of finite element simulation in this paper. The results show that behavior mechanism of negative Poisson’s ratio under dynamic crushing is the same with that at static loading of which is the cave-in or rotation,and this explains the necking phenomena of the stagger-arranged triangle and quadratic cells during the in-plane crushing. The results provide us a certain understanding of the dynamic behavior and energy absorption property of twodimensional cellular materials with a negative Poisson’s ratio and lay the foundation of the impact behavior of three-dimensional foam materials with a negative Poisson’s ratio.关键词：Honeycomb;Negative Poisson ’s ratio;Cellular materials;Dynamic crushing;Deformation mechanism
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发布时间：2022-09-22 - 摘要：Rolling element bearing is an important kind of machine element widely used in mechanical industry,and its internal stress condition has great influence on its service life. Considering the characteristic of elastic nonlinear contact in rolling element bearing,taking deep-groove ball bearing 6304 as investigation object,a flexible finite element dynamic model for contact nonlinear dynamic problem of a deep-groove ball bearing was established. Based on explicit dynamic finite element method,a nonlinear contact dynamic simulation was made and the kinematics characteristic of deep-groove ball bearing and contact stress of inner ring,outer ring and rolling element were obtained. The regularity of dynamic stress varying in motion process was studied.The results show that the present explicit dynamics finite element method is very efficient and reliable in solving complicated rolling element bearing dynamics stress,and it will become a useful means for the further work on rolling element bearing carrying capacity and service life.关键词：Deep-groove ball bearing;Finite element model;Dynamic stress;Explicit dynamics
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发布时间：2022-09-22 - 摘要：The mechanics model of crossed cylindrical roller slewing bearing under combined radial,axial and tilting moment loads was established,this model considers the clearance parameter of the slewing bearing. The mechanics model was numerically solved by using Newton-Raphson method. Two carrying capacity indexes that are safety factor and fatigue life of the slewing bearing were calculated,and the influence law of slewing bearing clearance on the internal load distribution,safety factor and fatigue life of the slewing bearing was analyzed. The results show that the change of slewing bearing clearance has significant influence on the internal load distribution and carrying capacity of the slewing bearing. With the increase of axial clearance of slewing bearing,the number of rollers inside the slewing bearing undertaking the external load decreases gradually,the load of the heaviest loaded rollers increases correspondingly. During the process of the axial clearance increase of the slewing bearing from 0 mm to 0. 24 mm,the carrying capacity safety factor of the slewing bearing decreases by 16 percent,the fatigue life decreases by 26 percent.关键词：Slewing bearing;Crossed roller;Mechanics model;Safety factor;Fatigue life
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发布时间：2022-09-22 - 摘要：Taking box girder structure of 36 t container gantry crane as research object,and combining with the finite element analysis results of crane structure,it carried out a safety assessment for the cracks on box girder structure using level 2fracture assessment method. Evaluation results showed that the six surface cracks were all in the safe range. It established the model of crack,determined evaluation parameters,made evaluation calculation,and drew FAD figure,which explored a set of safety assessment processes and methods suitable for the steel structure of crane. It has realistic meaning to guide crane structure safety assessment and eventually to form a unified standard.关键词：Crane;Box girder;Fatigue damage;Safety assessment;FAD figure;Assessment method
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发布时间：2022-09-22 - 摘要：Aiming at a complex polygonal honeycomb structure,using the virtual work principle,the analytic formulae for a honeycomb core deformation under the small deformation condition were derived by Euler ’s beam model. Then the analytic expressions for equivalent elastic modulus and Poisson’s ratio in two orthogonal directions were obtained and its correctness was validated by numerical simulations. Finally,the effects of wall angles and wall length on the honeycomb stiffness were explored by the analytic expressions. The results show that: the angle θ andφ of walls has a great influence on equivalent elastic modulus and Poisson’s ratio,and the changes of angleθ will lead to positive and negative changes of Poisson’s ratio; the equivalent elastic modulus decreases with the increasing of the length of wall.关键词：Polygon;Honeycomb core;Virtual work principle;Equivalent elastic modulus;Equivalent poisson’s ratio
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发布时间：2022-09-22 - 摘要：In order to do innovative design and study for the gears of shearer’s cutting part,the rigid-flexible coupling model of rocker system was established to study the thermal equilibrium procedure of the gear system,the temperature load and boundary conditions were determined and the different working conditions load files which were output by MSCAdams were loaded.Temperature-structure coupling analysis of the gears were studied by ANSYS,the temperature field nephogram and the structure coupling analysis nephogram of the gears were obtained. Combining MFC with ANNs could predict shearer ’s kinematics parameters when the gears was reliable operation,the prediction error reach 5. 6538 × 10- 6,the research results provides a unequivocal quantitative basis for the design and optimization of gear type parts which could improve this type of parts’ functional reliability effectively,this method has instruction significance to practical shearer’s productions.关键词：Shearer;Cutting part;Gear;Multi-field coupling;Artificial neural network
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发布时间：2022-09-22 - 摘要：To calculate the different meshing points stiffness of the internal gear pairs of planetary gear reducer of less tooth difference with biasing crankshaft,the parameter and engagement angle equation of the internal and external tooth of the reducer is established; the tooth is regarded as a cantilever beam with variable sections,the numerical model used to calculate the different deformation of the tooth is built respectively,and adopts the differential quadrature method when calculating the bending and shear deformations of the variable section beams,the Matlab program to compute the different meshing points stiffness is also compiled,the method is verified with living example and experiment. The results show that this method is accurate and quick,and provide an important theoretical basis for the further study on the vibration and the maximum carrying capacity of the reducer.关键词：Planet reducer;Less tooth difference;Meshing point;Stiffness
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发布时间：2022-09-22 - 摘要：In this paper,the buckling property of two kinds of corrugated skin structure was analyzed. The influence of radius,depth and number of reinforce slot on buckling load was studied. The constraint of reinforce slot interspace and machinability was also take into consideration. The research shows that the buckling load increases as the depth of reinforce increases. There is a critical line of reinforce slot radius,when being at left side of the line,the buckling load increase as the radius increases,and vice versa. There is a critical surface of reinforce slots number,when under the surface,the buckling load increases as the reinforce slots number increase.关键词：Wing skin;Corrugated structure;Buckling load;Parameter analysis
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发布时间：2022-09-22 - 摘要：The notch stress method（ NSM） is a local fatigue analysis method of welded structure,this method has high accuracy because it focus on the analysis of strain and stress of the fatigue weak area,such as weld toe and weld root. The article collected relevant literature of recent years,so the development history and basic principles of notch stress method had been reviewed; the similarities and differences of nominal stress method,structure stress method,and notch stress method were also summarized. Then latest research progress and development trend of this method were introduced from the following three aspects: the reasonable values of fictitious notch radii; the fatigue class assessment（ FAT） of notch; the slopes of notch fatiguelife curves. In the last but not least,the article showed some welded structures application examples of fatigue analysis with NSM in several industrial areas. Through the comprehensive introduction of notch stress method in this paper,it aims to provide beneficial reference for the domestic welded structure fatigue strength design.关键词：Welded structure;Notch stress method;Fatigue strength;Research progress;Application example
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发布时间：2022-09-22 - 摘要：According to theory of nonlinear vibration and Higher theory of plates and shells,the welding residual stress influence on stability of solution of nonlinear thin rectangular plate was studied to choose nonlinear rectangular thin plate possessed the welding residual stress as subject investigated. The conclusion which the stable and unstable regions of periodic solution of nonlinear rectangular thin plate possessed the welding residual stress has with the welding residual stress and change was gained. The conclusion which in different frequency ranges,the welding residual stress effects on stability of periodic solutions of different was obtained. The conclusion which the welding residual stress on the whole bring to reduce the stable region of periodic Solutions. The conclusion has certain guiding significance for the design of nonlinear rectangular thin plate possessed the welding residual stress.关键词：Welding residual stress;Nonlinear thin rectangular plate;Periodic Solutions;Stability
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发布时间：2022-09-22 - 摘要：Based on the bearing contact mechanics and heat transfer theory,thermal-structure coupling model of hollow cylindrical roller bearing for cone bit was established. Temperature,stress and deformation distribution of the bearing were analyzed,and influences of parameters on bearing’s thermal-structure coupling field were studied,such as hollow ratio,bit pressure,friction factor,revolving speed,grease temperature and well temperature. The results show that the maximum temperature of bit’s hollow cylindrical roller bearing system appears on the thrust bearing,the maximum equivalent stress occurs on the tooth claw journal,the maximum displacement occurs on the cone,and the maximum contact stress occurs on the hollow roller contact pair. With the increasing of hollow ratio,the maximum temperature,contact stress and deformation of the hollow roller gradually reduce,while the maximum equivalent stress decrease firstly and then increase. The equivalent stress of the hollow roller with hollow ratio 55% is minimal. Temperature,stress and deformation of the bearing parts increase with the increasing of drilling pressure,friction factor,revolving speed,grease temperature and well temperature. These results can provide useful references in designing and optimizing the bearing of cone bit,and benefit the application of cone bit in high temperature deep well.关键词：Cone bit;Rolling bearing;Thermal-structure coupling;Finite element;Temperature field;Stress
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发布时间：2022-09-22 - 摘要：A new load spectrum measuring method which can instead of the six-component measuring wheel was carried out in this paper. Through analysis the signal time-domain,a linear model between the axle head and the wheel was established. By using real-time signal transformation and mathematical statistics method,the collected load spectrum of vertical wheel load and the vertical acceleration of the axle head,an inference model were analyzed and discussed between the axle head and the wheel.The analysis method was validated by a reality car test. The wheel vertical load and axle head vertical acceleration calibrated was conducted by four pillars road simulation test bed,and the skid pad load spectrum was acquisitioned. Compared with the load spectrum of collected wheel vertical force and inference load spectrum of wheel vertical force,the correctness of model was verified. Finally,the results indicated that this inference method can replace the six-component measuring wheel for road load spectrum acquisition.关键词：Load spectrum;Acceleration signal;Wheel load spectrum;Correlation analysis;Skid pad road testing
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发布时间：2022-09-22 - 摘要：Failure assessment diagram（ FAD） is usually used to evaluate the safety of welded structures containing cracks.There are three assessment levels in BS7910. As the assessment level increases,accuracy is improved and more data is required.This standard is widely used in safety assessment of pressure vessels and pipelines. The working level of offshore crane is relatively high and fatigue cracks can be found on it during the routine inspection. However,due to its high cost and long cycle of maintenance,the productivity is seriously affected. Therefore it is vital to commence safety evaluation on the cracked structure. This paper utilized Shao Yongbo’s experimental data to establish the 3C curves of the cracked structure of offshore crane,and compared it with the 2A curves of the BS7910 standard. The result shows that the tendencies of both curves are the same and 2A curve is more conservative. Thus the structure can be evaluated according to BS7910. This paper offers the critical load of T-plate that contains certain dimension of crack according to level 2A evaluation.关键词：BS7910;Cracked T plate;Safety assessment;Ultimate bearing capacity;Critical load
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发布时间：2022-09-22 - 摘要：Aimed at fracture of transmission shaft about some kind of transport for bulk dry-mixed mortar,this paper designed a set of testing equipment which can test torque,run out,revolving speed. This testing equipment provides with analyzed data on fault diagnosis and maintenance of this kind of brand new car. This set of testing equipment was also applied to the fault diagnosis of concrete pump truck and mix concrete truck. The place where the fracture of transmission taken place is very complex and it is very difficult to do the stress measurement of the hot spot of fracture taken place. This paper converted the measure data of torque into the stress of the hot spot of fatigue by using the FEA. Calculating the fatigue life of shaft by combining the structural S-N curve and the modified Miner’s rule were carried out. This method can provide a way of calculating fatigue life of shaft of engineering machine.关键词：Transport for bulk dry-mixed mortar;Testing equipment;FEA;Rainflow counting method;S-N Curve;Miner’s rule
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发布时间：2022-09-22 - 摘要：Under the condition of isothermal lubrication taking a involute spur gear as research object,a involute spur gear contact-fatigue life model composed of the lubricated-contact analysis and the explicit analysis was established. The condition which jioned the factor of impact and oil supply was intruduced. Based on the method of multi-grid and multi-grid integration values of pressure and thickness of the film were obtained and substitute the values into explicit analysis. Mises equivalent stress distribution was obtained by explicit analysis and according to Smith-Watson-Topper contact fatigue calculation model,predicting the tooth-contact fatigue life. The result shows that with the increase of the degree of overlap,the danger zone alone the tooth profile closes to the node and the fatigue life also increases. The result also indicates that increasing the degree of overlap can effectively control the impact of the tooth surface contact fatigue life. Compared to full oil state,friction in the contact which lack oil led the fatigue life decreases and the danger zone tends to moved from the subsurface to the surface. The result not only shows the importance of the elastohydrodynamic lubrication in preventing the occurrence of contact fatigue,but also provided a theoretical basis for maching the tooth surface.关键词：Involute spur gear;Elastohydrodynamic lubrication;Explicit analysis;Fatigue life
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发布时间：2022-09-22 - 摘要：Based on uniaxial fatigue research,starting from the fatigue mechanism,a strain energy density and strength interference model based on the strain cyclic loading has been studied. The energy dissipation is equivalent to the stress growth.The relation of internal stress applied stress and the intrinsic strength has been established,Then consider the effect of notch stress gradient,make a research on the notched specimens of multiaxial loading fatigue life formula and the stress concentration factor with three different samples of experimental data to verify the correctness of the model under study. Preliminary research indicates that the model have a satisfied prediction ability for the referenced multiaxial fatigue test data.关键词：Multiaxial fatigue;High-cycle fatigue;Notch;Fatigue life prediction
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发布时间：2022-09-22 - 摘要：Traditional train load spectrum statistics are all based on actual measurements,using Weibull distribution to fit test results and calculate load at different levels. But the required testing mileage is long and the entire process is timeconsuming. It is also difficult to fit Weibull parameters. More importantly,the final results are not necessarily reflect the real characteristic of a sample due to the assuming of load distribution beforehand. In order to overcome the disadvantages of traditional load spectrum statistical methods,in this paper,we use kernel density estimation techniques in statistical work of side frame load spectrum for SRM80 full ballast cleaning machine’s T100 C new bogie,which is based on the use of rain-flow counting method in time-load history statistics. Results show that the kernel density estimation method can restore the original load spectrum,remedy the problems of shortage of small sample data and save manpower and resources for train load spectrum statistical work.关键词：Bogie;Load spectrum;Rain-flow counting;Kernel density estimation
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发布时间：2022-09-22 - 摘要：Based on the nonlinear contact theory,a finite element model of spring clip-III fastening system used in metro lines is established. The relation between fastening’s clamping force and vertical displacement of its finger is obtained. Stress level of spring clip is analyzed under different distance of the spring clip inserting into the shoulder. The influence of radius of the shoulder end on clamping force and stress is investigated. Based on numerical results,the radius of the shoulder end is optimized. Results show that the distance of the spring clip inserting into the shoulder greatly affects the contact state between the clip and the shoulder. A local stress concentration in the clip occurs at the clip’s backend arc surface that is contacted with the shoulder end. When the shoulder end radius is changed to 8 mm,the stress value of the local stress concentration area significantly decreases.关键词：Pring clip of rail fastenings;Shoulder;Radius;Optimal analysis
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发布时间：2022-09-22 - 摘要：Explosion-proof box is used for the protection of petroleum drilling equipment. Costly explosion experiments will be avoided and the development cycle will be greatly reduced if finite element method is chosen for the analysis of explosion-proof performance. Completed the transient dynamic response analysis in nonlinear material model based on MSC Nastran SOL400 module. Do the checking after we got various parts’ behavior of explosion-proof box under blast shock. The results could be the reference of explosion-proof box’s design or structural optimization.关键词：Explosion-proof box;Shock wave;Elastic-plastic dynamics;FEM
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发布时间：2022-09-22 - 摘要：In order to study the influence of testee’s crack growth on the vibration character of the system during the electromagnetic resonant fatigue testing,detailed FEA for modal and forced vibration with testees at different crack sizes were conducted. According to the results of the analysis,the dynamic relationships between the acceleration of the swing arm and the stress of the testee at different crack sizes are set up. The FEA results show that as the crack growing,the natural frequency and vibration character change accordingly,so it is necessary to change the exciting force to meet constant-load control request during the test. Finally,a method using the acceleration signal as the reference is proposed to achieve constant-load control.关键词：Electromagnetic resonant;Bending fatigue;FEA;Constant-load Control
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发布时间：2022-09-22 - 摘要：In order to investigate pressure resistance character of steel conveyor,The roller,conveyor,and traction guide were treated as test system model. The model of Mooney-Rivlin was defined as rubber covering attribute. Attribute of wire rope was defined as Isotropic. Covering and wire rope,traction guide and covering,wire rope and traction guide were set to glue binding. Rubber belts of wire rope core was simulated. Properties of pressure resistance of the St2000 type conveyor belt was researched. The numerical analysis results is that reduction pressure resistance close to 0 when the roller pressure are less than100 N. Pressure resistance nonlinearly increase with the increasing of pressure as the effect of cover layer of viscoelasticity and the hysteretic nature. The mean value of pressure resistance are 26. 3N when the mean value of pressure are 3000 N. Pressure resistance of St2000 type conveyor belt is measured. The results show that the mean value of pressure resistance are 27. 2N when the mean value of pressure are 3000 N. The results of experiments show that the simulating model is effective. The results provide basic for energy dissipation calculation of rubber conveyor belt.关键词：Rubber conveyor belt;Experiments;Sag resistance;Numerical analysis;Energy dissipation
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发布时间：2022-09-22 - 摘要：Taking a hatchback car as example in this paper,introduced the RCAR low speed crashworthiness test and evaluation methods. Then taking panel-rear out and C-shaped pillar as research objects,discussed the methods of vehicle low speed crash optimization design,through the experimental verification,effectively improved than optimization before.关键词：RCAR;Low speed crash;CAE;Optimal design
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发布时间：2022-09-22 - 摘要：As the main bearing part of the vehicle,most of the load was undertaken by the frame,so its performance directly influence the performance of vehicle. According to the special requirements for equipment of semi-trailers,a calculation model of the frame was established with the finite element method,which static characteristics under bending conditions were analyzed. Use with experimental results of electrical test strain,the correctness of the model and the analysis method is verified and to provide the basis for further improvement and optimization.关键词：Semi-trailer;Frame;Finite element analysis;Strain test
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发布时间：2022-09-22 - 摘要：To improve the contact state of shrink-fit tool holder and shank,the factors affecting the contact pressure distribution in matching surface are discussed. The shrink-fit tool holder and shank parametric model is established by ANSYS parametric design language commend stream. The pressure distribution on the matching surface is revealed by pressure sensitive films. Compared with the finite element analysis,the reliability of parametric model is verified. The contact pressure is calculated by getting the stress distribution of the matching surface on the holder. Calculations indicated that the average pressure,max pressure and uniformity on matching surface will decrease with the increase of holder thickness,inner diameter,length and angle of matching,but the trend and range of the pressure distribution are the same; increased the thickness of the shank and selecting the thickness of the shrink-fit tool holder properly is helpful to reduce the stress concentration.关键词：Shrink-fit tool holder;Shank;Contact pressure;Parameterized model
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发布时间：2022-09-22 -
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