最新刊期
期 1 ， 2015
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FAULT DIAGNOSIS OF PLANETARY GEAR TRANSMISSION SYSTEM BASED ON VIBRATION RELEVANT INFORMATION FUSION
摘要：Considering the facts that different measurement point information provide different sensitivity degree and vibration transmission make fault relate to each measuring point,the fault diagnosis model of vibration relevant information fusion were put forward. The method is to obtain the eigenvector of wavelet packet signal energy about the normal and 5 different fault states under 3 measuring points. The correlation coefficient of the energy characteristics were calculated for the same measuring point in different states and for different measuring points in the same state. By analyzing the characteristics of these two types of fusion information,the fault diagnosis model was established. In addition,the fault diagnosis model was inspected with 14 groups of signals to be detected,and the results were exactly consistent with the actual fault states. The support vector machine method was adopted to realize classification of 5 different fault states. The outcome was consistent with the actual fault states and it verifies the correctness of the established model of fault diagnosis. Analysis results show that the fault diagnosis model was established through the vibration relevant information fusion,and the model can reflect the characteristics of different fault states.By the model,the weak and the coupling fault were effectively diagnosed for complex gear transmission system.关键词：Wavelet packet;Correlation coefficient;Information fusion;Support vector machine;Planetary gear transmission system;Weak and coupling fault- 3
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发布时间：2022-09-22 - 摘要：Based on the definition of local Hilbert marginal energy spectrum,a fault feature extraction method for roller bearings is further proposed based on LCD and local Hilbert marginal energy spectrum. By using LCD,an original rolling bearing vibration signal could be adaptively decomposed into a number of intrinsic scale components（ ISC）,and then the time-frequency distribution（ TFD） could be obtained by applying Hilbert demodulation to all the components. According to the distribution of the signal energy revealed by the TFD,a local Hilbert marginal energy spectrum could be acquired once the lower and upper limit frequency for the corresponding frequency band are determined. Then the signal energy over this frequency band could be computed subsequently and regarded as the fault feature parameter. The analysis results from rolling bearing vibration signals show that the proposed approach can effectively extract the fault feature information.
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发布时间：2022-09-22 - 摘要：Changing a bearing rotor system of a motor as object,consider eccentric force,oil-film force,unbalanced magnetic pull and asymmetric stiffness,applying Newton’s second law the weak nonlinear vibration equation of the bearing rotor system of a motor is established. By means of the averaging method of nonlinear vibration,the first approximation solutions and corresponding to stationary solutions of the parametric and forced vibration of the system are obtained,and the numerical calculation is carried out. The effect of the electromagnetic parameter on the response curves of the Primary resonance of the system is analyzed. With the increasing of the rotor radius,airtight magnetic gap and core length,the response curves of the Primary resonance of the system move to right hand.关键词：Bearing rotor;Weak nonlinear;Electromagnetic force;Oil-film force;Primary resonance;The averaging method
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发布时间：2022-09-22 - 摘要：The scattering problem of the circular cavity in the circular domain to the elastic waves is one of the main research objects in NDT（ Non-destructive testing） applications which has not been solved theoretically till now,the complex method,special function addition formulae and the wave function expansion method are employed to study the dynamic response problem of the circular cavity defect in the circular domain to the out-of-plane distributing loading acting on the outside of the circular domain,theoretical computation method of the stress concentration factors（ DSCF） on the boundary of the circular cavity defect is given,and the variations of the DSCF of the defect boundary along with the disturbing frequency and the loading location are investigated,numerical examples are given to verify the theoretical conclusions and show the influence of the boundaries and the loads to DSCF.关键词：Circular domain;Circular cavity defect;Scattering of SH waves;Wave function expansion;Stress concentration factor
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发布时间：2022-09-22 - 摘要：A certain measurement system for flexible joint’s pivot point drift has been studied in this paper. The detection system consists of camera bracket,signposts,image processing module,pivot point calculation module,result processing module,industrial camera,data interface,industrial computer and some other auxiliary devices. Two signposts are fixed on the line at a certain angle to the center line of the swinging body to be measured. When the signposts swing together with the swinging body,the industrial camera will take continues samples from it. Then the samples will be transferred to the industrial computer by the data interface. After that the image processing module will get the signposts ’position in the measurement system plane coordinates by images denoising, background subtraction and signposts positioning. With this information the pivot point calculation module will calculate the average pivot point of two different samples to approach the momentary pivot position while the swinging body swings according to the mathematic model. The result processing module will record and visualize the pivot point movement trajectory. The precision of this measurement system is about 0. 5% which has been checked by simulation and proved by test.关键词：Pivot point drift;Machine vision;Image processing
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发布时间：2022-09-22 - 摘要：In order to fully exploit the useful information of winger Time-Frequency Spectrum,a fault diagnosis scheme based on winger distribution of vibration signal combining with singular value decomposition is proposed in this paper. Firstly,winger distribution is applied to analyze the original vibration signal,then,analysis to winger spectral matrix based on singular value decomposition is conducted,and characteristic sequences which reflect the mechanical fault state is achieved,finally,taking the singular value of winger spectral as eigenvector to do the fault diagnosis with Support Vector Machine（ SVM）. The experimental results show that this method can effectively extract fault features.关键词：Bearing fault;Vibration signal;Singular value decomposition;Winger distribution;SVM
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发布时间：2022-09-22 - 摘要：The effect of the adhesive thickness on the overall strength of single lap joints made by lightweight aluminum alloy was experimentally studied. The relation between the overall strength and the adhesive thickness is influenced by some intrinsic characteristics of adhesives,one of which is the adhesive toughness addressed by the present study. The results show that the variation of overall strength corresponding to relatively ductile adhesive is more remarkable compared to that corresponding to relatively brittle adhesive,especially in the comparatively small adhesive thickness range. When the adhesive thickness is larger than the critical thickness,the overall strength of the single lap joints appears equal to the bulk shear strength of the adhesives. The present experimental results agree with the previous model prediction.
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发布时间：2022-09-22 - 摘要：Derived from the hinge model for a single-edge notched bend specimen,a single specimen method to estimate CTOACof high strength and toughness pipeline steels has been established,by regression of load line displacement against the logarithmic ligament during crack extension. As to monitor the crack behavior after crack initiation directly from an instrument load-displacement curve,the linear correlation between the limit load and the square of remaining ligament width has been confirmed by applying a huge 40 k J instrumented pendulum machine onto standard pressed-notch API X80 DWTT specimens and employing key curve method,which also provides an experimental way to determine the material based parameter of A*σf,required by other CTOACestimation algorithm. As a result,in spite of the difference in the dynamic load endurance and energy consumption between full-scale and thickness-reduction sample plates,the evolution tendency of CTOA during ductile cracking are similar to each other. Moreover,CTOACvalues of both plates were determined to be constant over a given range of crack length from 25 to 40 mm within steady-state stage,independent of specimen geometry.关键词：Drop weight tear test;Instrumented impact testing;Crack tip opening angle;Pipeline steel
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发布时间：2022-09-22 - 摘要：The sub-impact phenomenon of a simply supported beam struck by a steel sphere were studied by the Hertz impact theory and the three-dimensional dynamic finite element method,and tested by a set of sub-impact experimental device self-designed and its corresponding transient measurement system of the sub-impact. The sub-impact phenomenon was thoroughly discussed and studied through the experimental tests and numerical simulations. The results show that:（ 1） the impact duration of the first sub-impact is coinciding very well with the Hertz impact duration;（ 2） The subsequence sub-impacts have some different characteristics from the first sub-impact. And their impact durations vary randomly around the Hertz impact duration,but their variation in general are coincide with the Hertz impact duration;（ 3） It shows that the complicated sub-impacts that look like random and sensitive to structural transient response are dominated by local impact-contact deformation,and their mechanism can be explained by the Hertz impact theory;（ 4） The theoretical analysis has shown that the processes of the subsequence subimpacts are influenced greatly by the global structure vibrations,in turn affecting sphere motion and beam vibration response,and eventually leading to the next collision is difficult to predict.关键词：Beam;Sub-impact;Experiment;Numerical simulation;Theoretical analysis;Impact duration
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发布时间：2022-09-22 - 摘要：A typical example of the damage failure of the thin-wall structure fasteners on aircraft was enumerated. The failure characteristics and its harmfulness of the thin-wall structure fasteners on aircraft were analyzed briefly. According to the fasteners loose and fall off failure problem of one sided connection structure of the leading edge of the wing on a certain aircraft,three improved design methods were put forward. And these fasteners with and without improved were experimental comparison verifyed by the tension-tension fatigue and the vibration endurance test methods. The impact vibrationn test device was developed to simulation or representation the failure mode and failure course of fasteners during vibration fatigue loading. A vibration fatigue test method on the thin-wall structure fasteners on aircraft was initially established. The results showed that there is essential difference on failure mode,damage mechanism,wreck destroy break appearance and pattern distributions of fatigue life of the thin-wall structure fasteners between the classical fatigue loading and the vibration fatigue loading. Based on the test results,the preferred and alternative improved design methods on the fasteners of one sided connection structure of the leading edge of the wing on a certain aircraft were provided.关键词：Aircraft;Thin-wall structure;Fastener;Failure mode;Vibration fatigue test;Fatigue life
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发布时间：2022-09-22 - 摘要：Quasistatic fracture toughness tests have done on SAW multilayer weld joint of Ni Cr Mo V scaled steel. The test result shows that the dispersion of fracture toughness J of SAW multilayer weld joint was large. J-R fracture resistance curve was fit and critical Jc（ 25）with pop-in behavior were calculated according to the different of brittle and ductile fracture phenomenon.The crack initiation parts of brittle and ductile fracture of multilayer welding specimens were analyzed respectively by scanning electron microscopy. There is a great relation between the multilayer weld fracture toughness and the position of pre-crack tip in the weld joints. Analysis and research have been done about the cause of formation of different microstructures of multilayer and effects on fracture toughness properties. It is known that the complex organization of bold columnar crystals, incomplete recrystallized coarse grain and incomplete recrystallized fine grain alternating exists is the essential cause of the large dispersion of fracture toughness.关键词：Multilayer weld;Microstructure;Fracture toughness;Columnar grained region;Fine grained region;Pop-in behavior
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发布时间：2022-09-22 - 摘要：According to the freezing adhesion problem which exists between the coal and the belt conveyor turnabout roller surface,the freezing adhesive strength test device is created. To simulate the belt conveyor turnabout roller surface environment,- 30℃ temperature and 3h freezing time of stress conditions,several different materials are studied with moisture content 30% of the coal slime,each of the freezing adhesive characteristic. Comparative tests have proved that UHMW-PE material in normal,tangential freezing adhesive strength is lower than test of other materials,which proves that it is provided with good anti-freezing adhesive capability. According to UHMW-PE package roller based on the actual application situation can further illustrate that the UHMW-PE can be used as roller coating in order to achieve anti-freezing adhesive effect.关键词：Anti-freezing adhesive roller;UHMW-PE;Normal freezing adhesive strength;Tangential freezing adhesive strength
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发布时间：2022-09-22 - 摘要：The uncooled infrared focal plane arrays（ UIRFPA） used in this micro-Raman experiment are composed of Si O2 thin film and Si substrate. They have the characteristic of MEMS microstructure. The process of the thermal oxidation may lead to the residual stress on account of thermal ecpansion coefficient mismatch and lattice mismatch. Residual stress in thin film has an important effect on the properties of the micro-elements. Therefore,it is necessary to measure the film residual stress. The residual stress in two Si O2 thin film / Si substrate has been investigated by using micro-Raman spectroscopy（ MRS）. The results show that the residual stress along the cross – section of the Si substrate is a quadric decrease along with an increase in the depth. By means of the force equilibrium and infinitesimal calculus,the residual stress in thin flim can reach 3. 3GPa and2. 2GPa respectively for two samples. Then it can be concluded that residual stress in thin flim is compressive considered the analysis of flim micro-element. In the releasing process of the residual stress,it may make film fold,bend,bulge,and even cause disorder for the film sample when the residual stress reaches GPa level.关键词：Micro-Raman spectroscopy;Uncooled;Focal plane arrays;Residual stress;Thin film
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发布时间：2022-09-22 - 摘要：The accidents of truck crane happen frequently during working because of the structure failure of hoist boom,which result in severe economic loss and casualties. So,the method combining probabilistic and non-probabilistic hybrid reliability theory with Bayesian Network is put forward to analyze the reliability of hoist boom structure. Probabilistic and nonprobabilistic hybrid model is built aiming at the interval variables and random variables to calculate the failure probability of boom buckling under different conditions. Bayesian Network model is applied to calculate the importance index of different failure cause. Finally,the validity of the method is verified according to the instance analysis,which can provide evidence for hoist boom design based on reliability.关键词：Reliability analysis;Probabilistic and non-probabilistic hybrid model;Bayesian Network;Boom buckling analysis
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发布时间：2022-09-22 - 摘要：Many aircraft structures are in thermal and vibration composite environment,and the two both should be taken into account in structural optimization design. Thermal environment influences the structural dynamic characteristics on the change of structural stiffness matrix,and then changes of the structure natural frequency. Basing on the analysis of structural dynamics in thermal environment optimization model was built both for uniform temperature field and thermal conduction structure Considering the manufacture process, the model optimizes the dynamic characteristics of structure. Results suggest that optimization considering the thermal environment of structural dynamics characteristics can improve the structure natural frequency and then keep the natural frequency away from the range of external excitation frequency to avoid resonance phenomenon caused by the change of the structural natural frequency resulting in thermal environment.关键词：Thermal;Vibration;Dynamic characteristics;Stiffness matrix;Natural frequency;Resonance
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发布时间：2022-09-22 - 摘要：when uncertainty information is not enough that it is so difficult to get the parameter probability model,the nonprobabilistic reliability analysis method could be taken into accout. This method described system parameters as interval variables first,measuring the system reliability through the ratio of security domain and the basic interval variables total area. Provided the calculation methods for probability of failure surface under different cases of combination of stress and intensity. Compared and analyzed the relationship between probability of reliability and non-probabilistic reliability when stress and intensity obey uniform distribution and normal distribution respectively. Finally,through typical numerical examples testified this analysis method.关键词：Interval analysis;Non-probabilistic measurement;Stress-strength interference model;Reliability analysis
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发布时间：2022-09-22 - 摘要：According to the requirement of the enterprise that the raw material of leaf spring clamp is replaced from QT500-10 to ZG650-830,in order to reduce costs,lightweight design is needed as a result. Based on the parametric finite element model of leaf spring clamp established by the adoption of ANYSYS Workbench,this article takes relevant parameters of the inner chamber as design variable,generates design parameter sample space through experimental design and confirms the optimization direction of structural parameters by acquiring the response surface of sample point from finite element solution as well as the conduction of sensitivity analysis on the design variable. Multiplication and division methods are adopted to conclude mathematical model of multi-objective optimization. And the Workbench is also applied for the size optimization design,acquiring a one-time lightweight leaf spring clamp model. Then,further topological optimization is conducted on one-time lightweight model to acquire the final one. This research shows that the leaf spring clamp after lightweight design can meet the requirements of intensity and stiffness with higher safety performance in structure,and the weight reduction ratio also amounts to 26. 78%compared with the original structure.关键词：Leaf spring clamp;Lightweight;Multi-objective optimization;Topology optimization
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发布时间：2022-09-22 - 摘要：According to the stochastic distribution of parameters,the reliability analysis of spring locking mechanism is carried out for helical spring by using probability theory and mathematical statistics. The optimization model of the locking mechanism spring parameters is established. Using Simulated Annealing Algorithm（ SAA）,the optimal parameters of spring are provided with the help of computer program compiled with Visual Basic language. The rationality of optimization result is verified by simulation results of the finite element model.关键词：Locking mechanism;Reliability-based analysis;Optimize design;SAA（Simulated Annealing Algorithm）;Numerical simulation
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发布时间：2022-09-22 - 摘要：Single point incremental forming（ SPIF） is a new metal forming method without Die ＆cutting. Using this method,the product cycle shorten,the production costs reduced. The main process parameters of the single point incremental forming : tool diameter d、the incremental depth ΔZ、sheet thickness sthimpacting on the simulation results are analyzed using Abaqus. Law of sine on incremental forming reaction sheet thickness variation is verified through simulation,the law of sine draw sheet thickness greater than the numerical simulation of the distribution is analyzed. thickness distribution of the sheet metal forming is presented,it’s application is analyzed.关键词：Single point incremental forming;Numerical analysis;Forming part partition
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发布时间：2022-09-22 - 摘要：The interference fit between HEV motor rotor shaft and dynamo sheets was discussed in this paper. Assembly stress was analyzed and fatigue life was predicted by CAE method to study the motor rotor’s structural reliability. Comparison with the Von Mises stress results under different assembling methods shows,proper use of interference fit can reduce the stress fluctuation of matching components in deferent rotational speeds. Deeply research proves that interference fit in rotational part’s radial direction can obviously improve the fatigue performance if high stress fluctuation caused by centrifugal force exists.关键词：Motor rotor;Interference fit;Assembly stress;Strength analysis;Fatigue life
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发布时间：2022-09-22 - 摘要：On the basis of the specific calculation example,the flexible and thin tube sheet was designed with methods of different countries respectively. Comparing the calculation results,the advantages and disadvantages of each design method can be evaluated. In order to study the main parameters,such as the thickness of tube sheet,the center distance of heat exchange tube and the radius of transition fillet,which influence the stress distribution characteristics of flexible and thin tube sheet,the tube sheet was analyzed by finite element software ANSYS. Finally,the appropriate structure dimension was confirmed.关键词：Flexible and thin tube sheet;Design method;Finite element;Stress distribution;Main parameters
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发布时间：2022-09-22 - 摘要：Based on the three-dimensional model of tripod constant velocity universal joint,considering the offset of the cases,analyzed and calculated the normal force,peripheral force of the roller,and its change rule with rotating angle and swing angle,and also analyzed the axial force,radial force and deflection torque generated by the friction during the transmission. And then,based on the Herzt contact theory and revised coulomb friction model,using ADAMS to do dynamics simulation analysis of those force,The result show that simulation results generally align with theoretical calculation results,the axial force,radial force and deflection torque changed with the swing angle,and under the conditional of a swing angle,those force changed with the rational angle.关键词：Tripod constant velocity universal joint;Friction;Axial force;Radial force;Deflection torque;ADAMS
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发布时间：2022-09-22 - 摘要：Based on the concept of contact counterforce between gear pair,the paper studied the meshing efficiency of involute spur gear mechanism,analyzed the effect factors of friction coefficient between contact tooth surfaces. Referring to the existent research models of friction coefficient,the paper discussed the meshing characteristics of spur gear and helical gear’s transmission,and derived the mathematic expressions of instantaneous meshing efficiency and average meshing efficiency for gear transmission of spur gear and helical gear. And then under the situation of different transmission ratios,pressure angles and friction coefficients,the paper analyzed the meshing efficiency of gear mechanism. The results show that friction coefficients are in inverse proportion to gear meshing efficiency,biggish pressure angles and transmission ratios contribute to improve gear meshing efficiency,and the meshing efficiency of increasing gear is higher than reducing gear.关键词：Instantaneous efficiency;Average efficiency;Friction coefficient
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发布时间：2022-09-22 - 摘要：Considering the nonlinear factors,the contact and friction between plates as well as bolt and plates,bolt preload,etc,three-dimensional finite element model bolted structure was developed. Three mathematical expressions of contact stress was deduced,which was based on the assumption that stress distribution in a circular cone. Compared with the finite element analysis,the corresponding deviation is within 9. 2%; Based on finite element computation,The influence to contact stress between connected components was analyzed with different thickness of the connected component,the clearance of the bolt hole and the diameter of nut. the experience formula of the connection stiffness was got,compared with the finite element analysis,the deviation of obtained member stiffness less than 5. 24%.关键词：Bolt connection;Preload;Contact stress;Connection stiffness
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发布时间：2022-09-22 - 摘要：Simulate and analyze the multi-pass welds in under-matched welded joint between CF62 and 316 L stainless steel with element birth and death technology by 3D finite element method. Design the under-matched welded joint based on equal-load theory. Found the multi-pass welds in under-matched welded joint whose shape is normal symmetrical X and the under-matched joint based on equal-load theory. The results show that the under-matched welded joint can reduce the residual stress compared with the normal well-matched welded joint. The under-matched joint based on equal-load theory has a smaller residual stress than the normal under-matched welded joint does so that it can improve the load capacity when it is used so the under-matched welded joint based on equal-load is more advantageous.关键词：Under-matched;Equal-load theory;Welded joint;Residual stress;Numerical simulation
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发布时间：2022-09-22 - 摘要：The inherent frequency of longitudinal vibration of a large section of conical horn was deduced by Rayleigh’ s approximate theoretical hypotheses,and the frequency of expression of correction is obtained. Effect of load on a large section of conical horn amplification coefficient and resonant frequency was studied. Modal analysis and the load characteristics of a set of large conic dimension transformers were analyzed by the finite element analysis. The results show that corrected result is closer to the value of the finite element simulation Compared with the one-dimensional theory and Its applicable scope is bigger. Along with the load increasing diameter and length of the system frequency will decrease gradually,and the amplification coefficient will increase Constantly and the effects of the diameter of a length is more significant relatively. The results provide a theoretical basis for design of conical horn section of engineering calculation and the compound horn and practical application.
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发布时间：2022-09-22 - 摘要：The crane lattice boom is complex and the load is diversity,part of the structure may suffer plastic deformation because of the high stress concentration or poor weld quality under exceptional poor load conditions. So using strain analysis parameter is reasonable compared to stress parameter. The paper was focused on the fatigue crack initiation stage of crane lattice boom. The method of local stress strain was used combined with the correction Neuber method. A crane fatigue crack initiation life evaluation algorithm model was built. According to the model,three main factors which will influence the initiation life calculation were analyzed and compared. Fatigue tests were also carried out with K nodes of crane lattice boom. When the material was determined under certain circumstances,the stress concentration factor had the most impact result on the life. The mean stress on the material had the less impact but it cannot be ignored. According to the Factors,optimization suggestions to lattice boom spatial structure and work process improvement measures were proposed.关键词：Crane;Lattice Boom;Crack initiation life;Method of local stress and strain;Influence factors;Structure optimization
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发布时间：2022-09-22 - 摘要：A measuring method was proposed to evaluate the dynamic fracture toughness of materials using pre-cracked Charpy impact specimens in this work. Different from the previous methods,a simple way to calculate the dynamic stress intensity factors of three-point bending specimen was developed based on the calculation of fracture specimen’s stiffness using Timoshenko beam theory. The fracture initiation time was detected experimentally and then used to determine the dynamic fracture toughness of materials. The calculated values were compared with the results obtained from finite element simulation,a good agreement was found from the comparison between the theoretical calculation and FEA,indicating that the current method proposed in this study is accurate,reliable and convenient for engineering application.关键词：Instrumented Charpy impact test;Dynamic fracture toughness;Three-point bending specimen;Finite element analysis
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发布时间：2022-09-22 - 摘要：Based on two stress criterions（ the maximum circumferential stress criterion and average circumferential stress criterion） for U-notches under Mode-I,relationships among the critical notch stress intensity factor,the fracture toughness and the tensile strength were built separately,which follows the similar idea of Seweryn regarding the crack as a special U-notch with the notch radius equaling to zero. By means of the critical fracture loadings for U-notched plates under Mode-I and the finite element results of Ansys,a new method has been proposed to measure the fracture toughness and the tensile strength. The three point bending and tensile experiments in related references of PMMA and aluminum alloy specimens with single-edged U-notch and graphite tensile plates with central U-notch were verified. It indicates that the methods are simple and can be applied in engineering because the U notches can be machined conveniently and the fracture load under Mode-I can also be obtained easily.关键词：U-notch;Brittle fracture criterion;Critical fracture loading;Fracture toughness;Tensile strength
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发布时间：2022-09-22 - 摘要：In this paper,the stress field and the stress- magnetic field theory for a crack domain are used to explain the principle of magnetic memory testing. The magnetic dipole model is employed to the quantitative research of crack length. The magnetic memory testing for different metal pipe cracks is made and the characteristics of magnetic memory signal are analyzed. It is shown that on the crack tip stress concentration appears,the magnetic field strength and it’s normal component reach the maximum. However,near the middle of the crack,the tangential component of the magnetic field intensity attends the crest and the normal component has zero-crossing feature. The crack length is approximately proportional to two parameters,the distance between the adjacent peaks of the tangential signal gradient,the distance between the peak and valley of the normal component of the signal. Based on the experiment,a calculation formula with good accuracy is suggested to determine the crack length and is proved by the experiment result.关键词：Magnetic memory testing;Metal pipe crack;Stress field;Magnetic dipole;Quantitative study
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发布时间：2022-09-22 - 摘要：when using the software of the finite element analysis for a numerical control machine tool,the key issue is to obtain a good result precision. The conventional structural analyses put interest in a single part of machinery and ignore the influences of accurance and reliability acted machine parts of cutting force,gravity and other external load between applied force and constrained assembly relationship for every part under actral working conditionst. The assembly relationship of a column milling ＆ tooling machinery was analyzed,the contact and node coordinate coupling was set in relevant structure position. the relationship of every key part of the machine tools was transferred to the finite element model and more closer to the actral working conditions. With comparing the result of finite element methods to the field test,the comparative result shows this analytical method that consider the assembly relationship between every parts can ensure the method feasible and reliable.关键词：Numerical control machine tool;Assembly relationship;Coordinate coupling;Finite element analysis;Test
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发布时间：2022-09-22 - 摘要：T-joint structure is one of the bus basic structures. This paper discussed the effects of triangle bracket size and four forms of triangle brackets（ double brackets added at vertical rod single side,double brackets added at vertical rod both sides,single bracket added at vertical rod both sides,single bracket added at vertical rod crossing symmetric sides） on the rigidity and strength of bus T-joint structure. The calculation by finite element method and experimental analysis showed that: 1Only double brackets added at vertical rod both sides in the four forms of triangle bracket can evidently increase both the rigidity and strength of bus T-joint,2Under the bending loads two forms can be selected compatibly for T-joint structure,3Under the torsion loads double brackets added at vertical rod both sides should be selected for T-joint structure. This research findings can be referred for joint structure design of bus body.关键词：Bus body;T-joint structure;Finite element method
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发布时间：2022-09-22 - 摘要：For one type of magnetic agitator,under the condition that the maximum torque was determined of the cylindrical magnetic transmission,which simulated on the two-dimensional magnetic torque model by finite element software ANSYS14. 0.And the key parameters were analyzed,such as the number of magnetic poles,the thickness of the permanent magnet and the yoke,the air-gap and so on,which affect the torque transmission. The key parameters could be optimized according to the simulation results,and the optimal structure of the magnetic transmission could be gained,the accuracy and practicability of the above design method were verified further by practical test.关键词：Magnetic transmission;Finite element;Magnetic torque;Optimization design;Test
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发布时间：2022-09-22 - 摘要：By using FEA,the strength and stiffness characteristics of motorcycle foot-pedal under extreme loads conditions with driver and passenger were analyzed. Based on these,topology optimization was conducted with inner ribs as design domains using variable density method. Meanwhile,one new model was obtained according to the topological optimum results and the feasibility of structure is verified. The deficiency of strength and stiffness of previous design is resolved. In this way,it can shorten the development cycle and provide the theoretic guidance for the design of homogeneous products.关键词：Finite element;Motorcycle foot-pedal;Variable density;Topology optimization
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发布时间：2022-09-22 - 摘要：The main winch of rotary drilling rig is mounted on the platform or the lower part of the drilling mast. Effects of mount position of the main winch on the drilling mast hydraulic cylinder load are discussed in the present article. Based on forces on the body of the drilling mast luffing mechanism,and the torque equilibrium around the hinge between the drilling mast and the triangle,a mathematic model of the drilling mast hydraulic cylinder load was established when the main winch was mounted on the platform,and another mathematic model of the drilling mast hydraulic cylinder load with the main winch mounted on the lower part of the drilling mast was also developed by simplifying the mathematic model with the main winch mounted on the platform. A simulation model was built up and analyzed in Matlab software. The results show that the drilling mast hydraulic cylinder load with the main winch mounted on the platform is relatively larger than that on the lower part of the drilling mast,the former is influenced by the lift-arm angle,and compared with the latter,the former exhibits relatively good stability. At last,the simulated results with the main winch mounted on the platform are testified by the experimental data.关键词：Rotary drilling rig;Main winch;Drilling mast;Mechanical properties;Simulation
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发布时间：2022-09-22
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