最新刊期
期 1 ， 2018
- 摘要：Based on the Kirchoff plate theory and Hamiltonian principle,the magneto-aeroelastic transverse vibration equations of rotating conductive circular plate were derived. According to principles of electromagnetic field combined with a simplified aerodynamic model,the expressions of electromagnetic force and aerodynamic load of rotating circular plate were given.The magneto-aeroelastic free differential equation of conductive rotating circular plate was presented by means of Galerkin method. The curves of natural vibration characteristics of circular plates with two boundary conditions were drawn respectively.The analysis on the law of the vibration natural frequency varying with magnetic flux density,plate thickness,aerodynamic load and rotation speed is presented. The relationship graphs of magnetic flux density varying with plate thickness,aerodynamic load and rotation speed are described in the critical damping case.关键词：Conductive circular plate;Magneto-aeroelasticity;Transverse vibration;Rotating motion;Electromagnetic field;Galerkin method
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发布时间：2022-09-22 - 摘要：Advanced support equipment is used for comprehensive tunneling roadway temporary support equipment,in order to improve the stability and optimize the structure of the advanced support equipment,carry on the dynamic stability analysis,establish advanced support equipment mainly for components-column dynamics model,and establish the parameters of the vibration differential equation,its dynamic stability region and the dynamic instability region,using the energy method to analyze the stability of the columns,to provide the basis for advanced support equipment dynamic stability criterion later.关键词：Supporting in advance;Dynamic stability;Energy method;Column
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发布时间：2022-09-22 - 摘要：A nonlinear model of a pinned-free long shaft rotor system with a stabilized support at arbitrary position is established by employing the generalized Hamilton principle. The lower-order polynomials are introduced to construct Ritz basis to analyze the critical rotational velocity of the system and the optimal position of the stabilized support. The result of the optimal position and the bifurcation shape are verified by applying the finite element method. Furthermore,the bifurcation modes and post-buckling solutions of the rotor system are investigated while the rotational velocity exceeding the critical value. The results show that the optimal position of the stabilized support for the pinned-free long shaft rotor system is at 73% length of the beam from the pinned end. While the rotational velocity exceeds the critical value,the trivial deflection loses its stability through the pitchfork bifurcation and the axial displacement loses its stability by the transcritical bifurcation. The investigation provides a theoretic basis for installing the stabilized support for the long shaft rotor system and for understanding the geometrical nonlinear effect of the system working at supercritical state.关键词：Rotor system;Stabilized support;Optimization;Geometrical nonlinear effect;Critical rotational velocity;Bifurcation;Post-buckling
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发布时间：2022-09-22 - 摘要：Scraper conveyor chain and chain gear transmission as the research object,analysis of the scraper conveyor load and no-load conditions chain dynamics,and numerical simulation of the scraper conveyor special point chain speed and tension are simulated. The results showed that: the most important parameter of the chain is the number of sprocket teeth,and the running stability of the scraper conveyor is proportional to the number of sprocket teeth,13 tooth sprocket stability is far stronger than 9 tooth sprocket scraper conveyor; polygon effect there side impact load on the chain tension fluctuation significantly higher than the no-load side; the reaction sensitivity of polygon effect is inversely proportional to the length of the chain length of the scraper conveyor and sprocket selection provides a theoretical basis,and to Study on dynamic characteristics of research methods and provides a theoretical basis.关键词：Scraper conveyor;Chain’s speed;Chain’s tension;Polygon effect
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发布时间：2022-09-22 - 摘要：In order to solve interference of the neighborhood size of the linear local tangent space alignment（ LLTSA） when used in fault feature reduction,in this paper,a fault diagnosis method based on linear local tangent space alignment（ NALLTSA） for dimension reduction is proposed. Firstly,the high-dimensional fault feature of mechanical vibration signal are extracted. And then,the neighborhood adaptive linear local tangent space alignment with Parzen window density estimation is used to reduce the high-dimensional set to the low-dimensional compressed sensitive feature subset. Finally,the corresponding relationship between low-dimensional feature and fault classes are established by using support vector machine（ SVM）.Dimension reduction with NA-LLTSA can effectively increase the discrimination of fault feature,and furthermore,SVM can further improve fault diagnosis accuracy with its excellent pattern recognition capacity. Finally,the effectiveness of the proposed method was verified through the fault diagnosis experiment of rolling bearing.关键词：Fault diagnosis;Dimension reduction;Neighborhood Adaptive linear local tangent space alignment（NA-LLTSA）;Support vector machine（SVM）
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发布时间：2022-09-22 - 摘要：A kind of pyroshock reduction device of honeycomb sandwich plate is designed,which takes the impact as the research object when satellite deploys the solar array. The dynamic model of shock response and the key points in design are explained in detail from the view of vibration reduction. Spring element was introduced to improve the honeycomb sandwich plate and its accessory structure,then,the shock characteristics of the system wartested. Dynamic response of satellite after setting the damping device was analyzed. The result indicates that the honeycomb sandwich plate on mounting plate can effectively reduce shock response,and meet the launching condition,so the design is reasonable.关键词：Satellite;Solar array;Pyroshock reduction;Honeycomb sandwich plate
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发布时间：2022-09-22 - 摘要：Aiming at the erosion operator for the mathematical morphological filter（ MMF）,the quantum-inspired weighting structuring element（ QWSE） is proposed based on the quantum theory to extract fault information of mechanical vibration signal.Firstly,after analyzing the system with multiple quantum bits,a method which is employed to map the quantum space to the real number space is presented and the calculation formula of the QWSE is obtained. Then in order to compute all the parameters of the QWSE,the stochastic characteristics of mechanical vibration signal is utilized to acquire the quantum-inspired weighting while the local feature of signal is utilized to generate the dynamic height of the QWSE. Finally,the QWSE is appied to analyze the running status of bearing. The results indicate that QWSE can extract the fault period correctly.关键词：Signal processing;Information extraction;Mathematical morphological filter;Structuring element;Quantum theory
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发布时间：2022-09-22 - 摘要：The feed forward neural network is used to predict the bearing life distribution in this paper,and puts forward the maintenance decision model based on the maintenance window. The mean and variance of the bearing life distribution are predicted by using neural network,and the life distribution of the bearing is obtained. A maintenance decision model based on the maintenance window is proposed and compared with the threshold value maintenance model. The relationship between different maintenance window position and optimal maintenance point is analyzed. The model is verified by using the data of the whole life of bearing,it is concluded that the maintenance decision model based on the maintenance window is better than the threshold limit maintenance window is better than the threshold limit maintenance model in a certain time interval by calculate the maintenance cost rate of the two models.关键词：Roller bearing;Feed forward neural network;Prediction;Maintenance window
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发布时间：2022-09-22 - 摘要：A road simulation test is carried out with a passenger car body. Six signals are selected as the target iteration signals of the bench test from the multiple measuring points which meet the requirements of the iterative point selection. A screening method based on the correlation between different acceleration signals was proposed. Statistical correlation coefficient between the acceleration signals,and filter out the two sets of target iterative signals with the largest correlation and minimum correlation. The bench test shows that the greater the relevance of the target iteration signal group,the higher the accuracy of the road simulation test.关键词：Correlation coefficient;Road simulation test;Iteration;Acceleration signal
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发布时间：2022-09-22 - 摘要：The mechanism of cracks initiation and propagation of high strength aluminum alloy rims for heavy vehicles were analyzed. Tensile testing machine,optical microscopy,scanning electronic microscope and energy disperse spectrometer detailed characterization of the mechanical properties,fracture morphology,crack characteristics and corrosion products of aluminum alloy wheel respectively. The results show that the crack is look like the shape"Z",expanding along the grain boundary and fracture;there are corrosive elements Cl and S at the crack initiation zone and crack extension area,with characteristics of typical stress corrosion. According to the actual assembly and service condition,it exist electric potential difference between aluminum alloy wheel and steel lock ring under the condition of corrosive medium,which will generate galvanic corrosion. After T6 heat treatment,there areηphase,S phase and θ phase on the grain boundary of 7 A04 aluminum alloy. In the corrosion environment,the matrix grain priority to dissolute itself as anodic,which makes the grain boundary become active path,crack propagation along the path lead to fracture.关键词：High strength aluminum alloy wheel;Stress corrosion;Intergranular fracture;Failure
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发布时间：2022-09-22 - 摘要：During the combined fatigue test of certain engine fan blade,the difficulty was how to combine low cycle fatigue and high cycle fatigue,and applied them to the assessment location of the blade. The modal analysis and test was carried to obtain the natural frequency of the blade and verify the accuracy of the model. By the static analysis and transient analysis of blade-wheel system,the critical part and the frequency of high cycle fatigue was acquired. Besides,the holder was designed and combined the blade into a system. Through the demonstration of simulation analysis and fracture analysis,high-low cycle combined loading was successfully applied to the assessment location of the blade. The results show that for the third-level fan blade,the regularity distributions of equivalent stress have a similarity under different revolving speed loads. The dangerous part of the blade is on the lug,and the max stress reached to 503 MPa. There are 2 risky resonance revolving speeds in the bladewheel system,which are n = 9 890. 92 r/min and n = 10 979. 8 r/min. The resonance frequencies are f = 1 318. 92 Hz and f =1 439. 65 Hz. There are typical characteristics of high-low cycle compound fatigue fracture on the cracked areas of the blade,such as fatigue line and fatigue striation.关键词：Fan blade;High-low cycle complex fatigue;Finite element analysis;Fracture analysis
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发布时间：2022-09-22 - 摘要：In view of the deficiencies of the main evaluation methods of viscoelasticity,the air-coupled ultrasonic evaluation technology was introduced with the characteristics of non-contact and nondestructive. Based on the theory of viscoelasticity and air-coupled ultrasonic,the theory and experimental method of the air-coupled ultrasonic evaluation for viscoelsaticity were proposed. The storage modulus,loss modulus and loss angle tangent were achieved through the measurement of reflection coefficient,wave velocity and attenuation coefficient. The testing study of air-coupled ultrasonic evaluation for viscoelasticity was carried out,the method was compared with the DMA testing,the results were very consistent. The advancement and accuracy of air-coupled ultrasonic evaluation for viscoelsaticity was proved.关键词：Air-coupled ultrasonic;Material viscoelasticity;Nondestructive evaluation
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发布时间：2022-09-22 - 摘要：Aiming at the phenomenon that the Huck rivet often falls off in the application of rolling stock,the quasi-static tensile test of Huck rivet was carried out by using the universal mechanical testing machine. The tensile performance curve of Huck rivet is obtained. The failure process of the riveting part is divided into five stages according to the test phenomenon and the drawing performance curve. In addition,the failure load of the friction pairs and the shear behavior of the rivet and the maximum shear resistance are obtained. After that,the quasi-static tensile test was carried out on the Huck rivet of the fatigue test under low stress and low cycle times,we can found that in the second half of the Huck rivet shear performance curve,there is a trend of instantaneous load reduction,but it has little effect on the maximum shear strength. The failure process is divided into four stages according to the performance curve. In order to improve the design of rivet joint and the fatigue test of Huck rivet.关键词：Huck rivet;Tensile test;Shear strength
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发布时间：2022-09-22 - 摘要：A short interruption occuring during the charging process influences the stress evolution. Two cases were considered here. In one case the galvanostatic charging process was interrupted while in the other case the potentiostatic charging process was interrupted. By solving the diffusion equation with an initial condition of general form,the analytical solutions of the concentration variation as well as the stress evolution of these two cases were obtained. Charging interruption leads to a short moment of stress relaxtion,but the stress recovers to increase once the charging is turned on again. Each time of interruption results in a rise-and-fall of the diffusion-induced stress. The longer the interruption lasts,the more severe the stress fluctuation is,which is dentrimental to the battery life. The up-and-down phenomenon in the stress is more obvious for interrupting the galvanostatic stage than for interrupting the potentiostatic stage. The most severe stress fluctuation occurs when the interruption happens near the switching moment between the galvanostatic stage and the potentiostatic stage.关键词：Stress evolution;Charge shut-down;Galvanostatic charge;Potentiostatic charge;Lithiumion battery
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发布时间：2022-09-22 - 摘要：The sensitivity and reliability of packaged high-g MEMS accelerometer strongly depends on die attach quality that should pay special attention in the operation. A package method based on die attach is presented for a prepared MEMS high-g accelerometers by using two die attach adhesives with different elasticity modulus. The effect of the die adhesive on the performances has been studied by using finite element analysis（ FEA） and Hopkinson pressure bar measurement system simultaneously. With the consistent package process,we have experimentally demonstrated that the characteristic of dynamic sensitivity for the prepared MEMS high-g accelerometers increases with the increasing of elasticity modulus of the die attach adhesives. From this result,it is possible to fabricate MEMS high-g accelerometer with bigger sensitivity by applying die attach adhesive with bigger elasticity modulus.关键词：Packaging;Die process;High-g MEMS accelerometer;Elastic modulus;Finite element analysis（FEA）;Hopkinson Bar
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发布时间：2022-09-22 - 摘要：A reliability analysis method for complicated mechanical system is proposed which is based on Copula Bayesian network. Since the variables in complicated mechanical system are numerous and correlated to each other,the traditional analysis methods are incapable to solve the problems. However,the Copula Bayesian network takes advantage of both Copula function and Bayesian network,it can takes the correlation of variables into consideration by using Copula function,and makes probability inference of reliability at the same time. The CBN structure was transformed from BN at first,and then local t-Copulas were modeled based on the marginal distributions and correlation coefficient matrix of variables. The reliability of an jack-up gearbox was analyzed by CBN,and the correlated structure of nodes was obtained. The failure probability of gearbox was calculated by CBN,and the result showed that it was more secure and accurate than the traditional BN method.关键词：CBN model;Correlation;Multivariate variables;Jack-up gearbox;Reliability
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发布时间：2022-09-22 - 摘要：The unsprung mass of an electric vehicle is increased because of the placement of electric driving system,which deteriorate the vehicle handling stability. Therefore,the light-weight design of the wheel-side reducer is a crucial problem that requires to be solved. The main topic of this paper is concerning light-weight design methodology for the reducer shell. The design objective is the satisfaction of high durability test life requirement while guarantee of rigidity and intensity requirements.Firstly,the main load and static strength were analyzed. Results showed that the max stress was far lower than the fatigue strength so that a light-weight design work was required. The allowable max working stress was calculated according to the fatigue life requirement. A structural optimization result was calculated by setting the max stress as the constraint and the minimum volume as the objective. Finally,the optimized shell’s fatigue life was predicted by applying virtual fatigue simulation method. The simulation results showed that the shell was furthest light-weight designed on the basis of satisfying specified durability test requirement.关键词：Wheel-side reducer;Lightweight design;Topological optimization;High fatigue endurance
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发布时间：2022-09-22 - 摘要：The vibration environment of an inertial navigation system（ INS） can bring an adverse effect on its measurement accuracy. A random vibration model of an optical fiber INS is proposed. It is used by a substructure synthesis method based on frequency response functions. According to this model,a design sensitivity expression in terms of partial derivatives of shock absorber physical parameters and root mean square（ RMS） response of IMU is presented. Compared with the central difference method,the analytical method is verified via a numerical example. Besides,the stiffness of the shock absorber is optimized in order to minimize the rotation of IMU. The result demonstrates that the rotation of IMU is obviously reduced,and the system’s vibration coupling is effectively suppressed by the proposed method. It shows that the method is effective.关键词：Inertial navigation system;Sensitivity analysis;Substructure;Parametrical optimization
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发布时间：2022-09-22 - 摘要：Based on Pearson-Ⅲ distribution（ P-Ⅲ） representing much capacity for fitting extreme value data,research on Nzextreme values were carried on. Calculation method on the deviation coefficients Φp of skew coefficients Cswas deduced and established,which eliminated look-up and interpolation errors. In consideration that there was not uniform quantitative judge standard on optional curving fitting when fitting real data by P-Ⅲ distribution on the curve-fitting method,Using the maximum membership principle judged curving fitting level according to fuzziness of flight data,and membership function was deduced in detail. Finally through calculation and analysis the conclusions were obtained: it’s scientific and rational that Nzextreme value was conformed with P-Ⅲ distribution from the aspects of mean relative error,maximum error and degree of membership between fitted values and real values,and that membership function seen as optimized objective function was more advantageous than curve-fitting method.关键词：Normal overload;Predicting extreme value;Pearson-Ⅲ distribution;Degree of membership;Deviation coefficient
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发布时间：2022-09-22 - 摘要：The optimization problems of binary functions widely exist in many practical engineering problems,their global optimization methods have always been one of the hot research issues. A high effective method of global optimization to nonnegative binary functions was put forward basing on the maximum modulus theorem of the analytic function of complex function,this method can simplify the optimization problem of the object function on a two-dimension bounded area as an one-dimension global optimization problem,the theory basis for the optimization method was given,and three numerical examples were given to show the effectiveness of the method. On one hand,the conclusions obtained in this paper can be directly used to solve the optimization problem in which the analytic function theory could be used,on the other hand,it can be used to obtain the global optimization solutions of the two-dimension mathematical optimization problems in which the method could be used in a high precision and high effective manner.关键词：Optimization of non-negative two-dimension function;Maximum;Complex function method;One-dimension optimization
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发布时间：2022-09-22 - 摘要：A finite element model is established for the pre-stressed composite pyramidal lattice structures. The influences of prestress on the contact force, contact duration, structural deformation, energy absorption and impact damages are investigated. Before subjected to low-velocity impact,the composite pyramidal lattice structure is pre-strained by the static responses. The numerical results indicate that pre-stress has no significant influence on the peak contact load,contact duration and rate of total energy absorption,while it plays an important role on the deformation. When the impact velocity is constant,the maximum displacement of impact center increases with increasing the tensile pre-stresses,but the maximum deformation of the bottom facesheet and the truss cores incline to decrease when tensile pre-stresses increase,while the effects of tensile pre-stresses on the structural deformation are otherwise.关键词：Prestress;Composites;Pyramidal lattice structures;Low-velocity impact;Finite element analysis
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发布时间：2022-09-22 - 摘要：The multi-corner tubes with extra concave corners in cross section were presented to improve energy absorption efficiency of aluminum alloy thin-walled tubes in this paper. The axial crushing energy absorption capacity of square and multicorner aluminum alloy thin-walled tubes was compared with the same cross-sectional perimeter and mass. The improved method of folding element was applied to predict the crushing forces of thin-walled tubes under axial impact. The corners on cross section were discussed for the effect on axial crushing energy absorption capacity of the thin-walled tubes. The results show that the increasing performance of energy absorption of aluminum alloy thin-walled tubes is due to the increasing number of corners on cross section. The number and size of corners both have important effect on the crushing force efficiency of multi-corner tubes.The maximum crushing force efficiency of multi-corner tubes is 11. 6% higher than that of square tubes with the same material consumption of thin-walled tubes. The multi-corner tubes with 12 corners show better energy absorption capacity than the tubes with more corners which could lead to the small size of corners or the unstable deformations. The high axial crushing energy absorption capacity of the multi-corner tubes prefers increasing the corner number and corner size of adjacent sides at the same time.关键词：Thin-walled structures;Axial impact;Energy absorption;Aluminum alloy;Finite element
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发布时间：2022-09-22 - 摘要：The effect of change of load,gap between the pin and plate hole and frictional coefficient on the maximum contact stress was studied. FEA result was compared with several formula calculation results. When the gap of pin and hole△R = 0,the average bearing stress formula can be adopted; when the ratio of gap between the hole and pin to radius of the pin λ≥0. 02,in order to save cost for FEA analysis the Hertz formula can be adopted if no other more accurate calculation methods are available The computing error between the Hertz formula and FEA is less than 10%.关键词：Towing delta plate;Pin-loaded lug;Contact stress;Average bearing stress;Hertz theory;Finite element analysis
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发布时间：2022-09-22 - 摘要：This paper,based on finite element method,analyzed the profile modification of involute spline coupling,and investigated the effects of modified quantity and modified position,as well as considered the effect of profile modification on angular misalignment of involute spline coupling. The results show that: the contact pressure and contact length of modified spline coupling increases with the increase of applied torque. The maximum contact pressure first decreases and then increases when both of modified quantity and modified position increases,and the best modified quantity making the maximum contact pressure minimum increases with the increase of the amount of angular misalignment. The appropriate profile modification of involute spline coupling can effectively reduce the maximum contact pressure and the phenomena of concentrated contact stress,and improve the tooth surface contact pressure distribution,and mitigate the adverse effects caused by angular misalignment.关键词：Spline coupling;Profile modification;Contact pressure;Misalignment;Finite element method
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发布时间：2022-09-22 - 摘要：In order to improve the design method of pressure vessels strength,applying the theory of statistical hypothesis testing,the precision comparison method for design formula expansion applied range was established. Based on 52 groups of measured burst pressure of steel wall single-layer cylinder,the precision of mid-diameter formula with the Tresca formula was compared,and the application of formulas was extended according to the principle of no precision reduction. The research shows that:（ 1） According to the design pressure,benchmark scope and plans to expand the scope of mid-diameter formula are determined,respectively.（ 2） According to the relationship between design pressure and burst pressure,sample test data of measured burst pressure of the benchmark scope and plans to expand the scope are definite,respectively.（ 3） At the saliency of0. 05,the ratio of the sample and mid-diameter formula calculated value is random variables with the normal distribution,respectively,which sample located in the benchmark scope and plans to expand the scope.（ 4） The precision of mid-diameter formula in plans to expand the scope and the benchmark scope is same basically; the precision of Tresca formula in plans to expand the scope is higher than the benchmark scope.（ 5） When suitable scope extended to the design pressure less than100 MPa,the precision of mid-diameter formula and Tresca formula is same basically.关键词：Pressure vessels;Mid-diameter formula;Tresca formula;Application range;Expansion;Burst pressure;Precision comparison method
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发布时间：2022-09-22 - 摘要：Free spanning submarine pipeline work in the harsh condition and has many failure modes. Vortex-induced vibration is a significant cause leading to its fatigue failure. In order to study the law about different spanning clearance ratio and flow rate impacting on VIV strength of free spanning pipeline,this paper applied the software FLUENT to simulate twodimensional flow around actual diameter pipeline at high reynolds number and obtained the data about vortex shedding shape,lift coefficient and drag coefficient curves. The result indicates that: the lift coefficient amplitude and drag coefficient mean value of free spanning submarine pipeline decrease with clearance ratio increasing and gradually stabilize at last. In the case of small clearance ratio,lift extreme value is inequality on both sides of the pipe caused by the pipe bottom flow rate increasing. The lift coefficient amplitude and drag coefficient mean value present a trend of increasing first then decreasing with flow rate increaing,which is consistent with the conventional flow around a cylinder. Lift coefficient frequency increases with flow rate increaing and less affected by the clearance ratio. In engineering practice,water areas of high current velocity and large submarine spans should be avoid as much as possible to lay submarine pipelines and vortex-induced suppression device should be provided in danger sections.关键词：High reynolds number;Free spanning submarine pipeline;Numerical simulation;Vortex-induced vibration
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发布时间：2022-09-22 - 摘要：In order to make the exciting force adjustment of inertia vibrator during operation possible,and to meet the demand of particular vibrating machines,a kind of inertia vibrator is designed,it’s eccentric mass can be adjusted by pressure air. The design principal,structure design,analysis and calculation model is established. Furthermore,the relationship of centrifugal force to rotating speed,pressure,as well as the both,and the equations and curves are drawn and established. The research results could be guidance for design and production of institutes and factories.关键词：Inertia vibrator;Adjustable exciting force;Adjustable eccentric mass
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发布时间：2022-09-22 - 摘要：Based on the urban railway transportation vehicle wheel,three kinds of typical wheel plate（ straight plate,single S plate and double S plate） were set up. The study presents the calculation method of structure load and thermal load of the urban railway transportation vehicle wheel,and focuses on the thermal-mechanical coupling performance of the three types of wheel plate under different abrasion,the characteristic of the thermal-mechanical coupling stress is obtained under the thermal-mechanical coupling condition. The results show that three kinds of urban railway wheels are all satisfied with the requirements of fatigue strength; and the double S plate wheel has a better anti-fatigue performance than straight plate and single S plate wheel in the coupling field.关键词：Different plate;Rail wheel;Different abrasion;Thermal-mechanical coupling
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发布时间：2022-09-22 - 摘要：On the basis of two-dimension finite element analysis,the two-dimension stress intensity factor correction coefficients of typical lug joint were obtained; Three dimension elastic plastic contact finite element model of the typical lug joint was simulated and analyzed,and the lug thickness correction factor was introduced. Based on the results of two-dimension stress intensity factor correction and three-dimension finite element stress intensity factor simulation,the plug thickness correction factors were fitted,then get the expression of stress intensity factor of three-dimension model ofⅠtype crack in typical lug joint.Finally the corresponding stress intensity factor expression was carried out to verify the accuracy,which combined with the corresponding residual strength test. The results show that the stress intensity factor calculation formula is accurate.关键词：Stress intensity factor;Three-dimension model of typeⅠcrack;Lug joint;Finite element analysis
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发布时间：2022-09-22 - 摘要：The location and size assessment of different boundary conditions of plate and the effect of the sensor arrangement and noise for damage identification were carried. The principal process includes: firstly,the natural feature parameters of intact and damaged structures were obtained by the finite element modal analysis of thin plate. Modal nodes displacement data of the rectangle thin plate was decomposed and evaluated using the discrete wavelet transform,and the high frequency information and singular value of the damage location were received. Secondly,damage identification of plate structure under different boundary conditions were performed,and the quantity estimation of damage degree is estimated quantitatively by the change rate of the maximize value of wavelet coefficients. Finally,wavelet coefficient of 4 clamped constraints is bigger than that of 4 simply supported constraints about 0. 5%,and 0. 88% comparing to the 2 clamped constrains. The cases of the size of grid g = 40 m and wavelet de-noising for signal are able to identify plate’s damage,effectively. The study results show that this method is valid for the damage identification of location and damage severity of 2 D plate,which can be expected to provide some thinking and reference value for vehicle structures’ damage identification.关键词：Structural damage;2D discrete wavelet transform;Damage identification;Wavelet coefficient
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发布时间：2022-09-22 - 摘要：Apply Arbitrary Lagrangian Eulerian（ ALE） and Archard wear theory to establish wheel wear analysis model of CRH5,by finite element static and steady state analysis,combined with repair operations to obtain the wheel wear law under typical conditions,including dynamic distribution regularity along the surface of the wheel tread wear degree and wear volume.Fatigue life of the worn wheel was also studied based on steady state analysis to get the evolutional law of the fatigue damage rate of wheel changing with the amount of wear. The results show that the fatigue damage rate of the wheel is significantly decline initially however being steady when it’s over 70% of the whole simulation wear loss.关键词：Wheel wear;ALE;Finite element method;Fatigue damage rate
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发布时间：2022-09-22 - 摘要：Loading spectrum statistic acquired from proving ground has great effect on the component fatigue life prediction.a fatigue damage and life prediction method based on the acceleration signal was put forward,this method is applied to engine mount bolt whose loading spectrum can’t be directly acquired in working condition. First,by macrofracture observation and mechanical model analysis,the relationship between the main stress load and acceleration load of different condition was defined.Then according to the S-N curve of engine mount bolt,and applying the acceleration signal in different working condition,bending moment and tensile stress in time series was calculated. The engine mount bolt fatigue damage was figured out based on those time series. Finally,by compearing with the fatigue life of two measured roads,the equivalent relationship between the two roads is established.关键词：Mounts bolts;Acceleration signal;Load spectrum;Fatigue life;Equivalent relationship
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发布时间：2022-09-22 - 摘要：The rubber stator of PCP used for oil recovery is studied in this paper,Through the fatigue tension test of stator rubber material,establish of stator rubber S-N curve; The analysis of the finite element mechanical properties of PCP,determine the most likely fatigue failure position of screw pump is near the high pressure chamber spiral sealing belt; Prediction of fatigue crack formation life of stator rubber of PCP by Fe-safe,determine the the minimum fatigue crack formation life and safety factor of each model of the stator rubber of PCP,and it decreases with the increase of chamber pressure,And the relation between the fatigue crack formation life and the chamber pressure of the rubber stator is obtained.关键词：PCP;Stator rubber;Crack initiation life;S-N Curve;Fe-safe analysis
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发布时间：2022-09-22 - 摘要：According to the characteristics of structure of the crane box girder and its complex stress condition,an equivalent crack approach based on fatigue test data is presented to estimate the fatigue life. The fatigue test data can be well in reflecting the effect of stress concentration on fatigue risk points. The stress concentration effects at the fatigue dangerous location can be approximately equivalent to having a crack in an unwelded plate. Using paris law calculate the equivalent crack propagation. By comparing estimation results with fatigue test results in the literature,the proposed method is effective and feasible to estimate the fatigue life under constant amplitude loading,but it needs to be further researched for estimation fatigue life under variable amplitude loading.关键词：Crane;Box girder;Equivalent crack;Fatigue life;Estimation
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发布时间：2022-09-22 - 摘要：As one of the key transmitting components and wearing parts of scraper conveyor,There are different types of wear which result to the failure of flat type chains. This study focused on the failure of the flat chains of Joy scraper conveyor used in Shendong Coal Mining Group. 3 D scanner was used to acquire the surface details of both worn and unworn flat chains. The data were then used to reconstruct the solid 3 D models of these two parts. Software package CATIA was employed to compare the models,including the wear volumes,positions and quantitative analysis of wear. The results showed that wear is the main failure mode of flat chain,but flat ring and ring have different Wear and wear positions. It provides a reference for people who engaged in mining machinery for failure analysis and laser repair wear flat chain.关键词：Scraper conveyor;Flat chain;Failure mode;3D scanning;Reverse engineering
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- 109
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- 2
发布时间：2022-09-22 - 摘要：Taking mechanical and electrical properties of PV modules with different fixed spacing on trackers as the research subject,the feasibility of the two fixed spacing schemes is confirmed in the design and construction of the project by the measured deflection,power attenuation and indistinct cracks from TUV institute test. Furthermore,combining the theory of finite element and ANSYS software,the finite element model of the PV module is established,and the guideposts of the calculation result is proposed after the rationality of the model is proved by comparison between numerical simulation result and measured date. The model which can make a security assessment of the mechanical and electrical properties about PV module is significant for security and cost control of project.关键词：Horizontal single-axis tracker;PV module;Fixed spacing;Mechanical test;Finite element;Deflection;Stress;Indistinct Cracks;Cost
- 3
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- 142
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- 2
发布时间：2022-09-22 - 摘要：In order to study the scraper conveyor load distribution in the process of cutting,a mathematical model between plow performance parameters and scraper conveyor transport performance parameters was established. Using numerical simulation obtained scraper conveyor loading capacity curve in condition of different planing speed ratio,different scraper conveyor lay length and different plow initial position,and analyzing its fluctuation characteristics. The results showed that: the maximum loading capacity of scraper conveyor is related to conveyor lay length,cutting speed ratio,plow face height,plow planing thickness,entity density of coal and so on,is independent of plow initial position; after reaching the maximum loading capacity of scraper conveyor,when planing ratio is odd,the loading capacity maintain maximum and constant,planing speed ratio to another value,the loading capacity presents fluctuation periodically.关键词：Craper conveyor;Load distribution;Numerical simulation
- 4
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- 82
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- 1
发布时间：2022-09-22 - 摘要：Joint design and motion research is key to the design and research of entertainment Anthropomorphic robot,It direct impact on attitude and balance of robot motion. So,we focus on research Joint structure design and joint movement. Joint of robot hand and foot is designed by human engineering principle and finite element analysis method. Solution of joint position and velocity is obtained base on establishing joint coordinates and calculation. Effective solve robot movement in the process of stability with analysis of the balance of motion. Find a way to achieve robot walking,turning and lateral movement and other humanoid movements by the study the effect of the slip and calculation of the sliding force. A fixed frequency current control method is proposed,and realized robot key gait planning.关键词：Entertainment anthropomorphic robot;Joint design;Movement research;Gait planning
- 4
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- 160
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- 2
发布时间：2022-09-22 - 摘要：In order to suppress the vibration noise of a tumble dryer（ internal barrel） in a pulsator washing machine,and to optimize the internal barrel for better performance,firstly,a parameterized finite element model of the internal barrel was established by Solidworks software and imported into ANSYS Workbench software. After analyzing it and obtaining the main parameters that effect the performance of an internal barrel,the independent variables were decided for the structure optimization design of the internal barrel. Secondly,Design of Experiments and Response Surface Methodology were combined to solve a multi-objective optimization problem,under the condition of improved strength and stiffness,solution with the lightest mass is choosen as the optimization goal. Using Central Composite Design in ANSYS Workbench software,experimental points were selected,and the response surface model of an inner barrel was built. Goodness of fit evaluated the fit of the response surface model to experiment data and assessed optimization parameters,then obtained the optimal solution.. Finally,an internal barrel model was built using the optimized size. The results of its dynamic finite element analysis show that the strength and stiffness of the optimized inner barrel are improved,at the same time,its quality is reduced by 5% and its dynamic performance is improved. It provides a theoretical basis for a structure optimization design of the actual product.关键词：Pulsator washing machine;Response surface method;The finite element analysis;Design of experiment;Multi-objective optimization
- 4
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- 354
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- 1
发布时间：2022-09-22 - 摘要：In order to solve the present situation of big dispersion degree of the slotted jack contact separation force,Finite element simulation and Taguchi method is proposed to optimize the range and the dispersion degree of the separation force. The structural parameters that affect the separation force of the slotted jack were analyzed,the separation force of the slotted slot in different groove depth（ h）,slot width（ d） and interference amount（ δ） was calculated by the finite element simulation model,The simulation data were analyzed by Taguchi method,The results show that the combination of the parameters is h = 3. 7 mm,d= 0. 3 mm,δ = 0. 05 mm has the strongest anti-interference ability when the separation force range is 0. 3 N 0. 8 N. The separation force test was carried out before and after the size optimization,The results show that the separation force of the jack is from 0. 524 N to 0. 539 N,and the standard deviation becomes from 0. 094 to 0. 078. The optimization of the separation force of the slotted jack based on finite element simulation and Taguchi method provides a reference for the optimal design of the contact.关键词：Slotted jack;Separation force;Finite element simulation;Taguchi method;Size optimization;Electrical connector
- 4
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- 140
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- 3
发布时间：2022-09-22 - 摘要：Lug joint is a kind of structure widely used in missile empennages connection. Aiming at the problem of the lug joints in a static experiment,we built the equal simplified FEA model,and systematically analyzed the influence of bolts distribution,stiffness matching of connected parts,bolt fit clearance and bolt preload on stiffness and strength of the joints.Finally,based on the analysis and manufacturability,the original structure got improved and validated by FEA simulation.关键词：Lug joint;Empennages connection;Connection stiffness;Load bearing capability
- 4
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- 135
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- 0
发布时间：2022-09-22 - 摘要：To predict the cutting force of cutting Si C particle reinforced aluminum-based compositeaccurately,an innovative theoreticalanalytical method is proposed in consideration of the influence of Si C particles on aluminum substrate. This method is built on the orthogonal cutting model,cutting force is considering to derive from threedeformed zones,namely,primary shear zone,primary friction zone andplough zone. Shear force,sliding and rolling friction force and plough force is analyzed based on the three deformation area,which is decomposed in X,Y,Z direction. To verify the validity of this method,turning experiments on 50% particles Si Cp/Al composites are conducted on CA6140 A turning-lathe by using PCD cutting tool. Experimental results show that the analytical methodcan be used to predict the cutting force accuratelyon the conditions of some cutting parameters.关键词：SiC particle;Deformed zones;Cutting force;Shear force;Friction force
- 4
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- 206
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- 1
发布时间：2022-09-22 - 摘要：Water recycle system is formed by shell and tube waste heat boiler body,drum,down comer and riser. The riser connects boiler body and drum. When the production of steam is less account in the system,the riser supports the whole mass of boiler drum and bears internal pressure,boiler drum’s operating mass,seismic load and wind load. In this paper,FEA of riser was completed by ANSYS,and the local stresses on the shell were studied with the change of different thicknesses of riser. Thus,the thickness of riser was confirmed to achieve material rationality and economical efficiency.关键词：Riser;Seismic load;Wind load;FEA;Local stress
- 3
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- 82
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- 1
发布时间：2022-09-22 - 摘要：The basic theory and solution flow of Franc3D were firstly focused,then elliptical embedded crack and semielliptical surface crack were employed to verify the stress intensive factor calculation accuracy from Franc3D and typical sheet problem was utilized to validate crack growth analysis reliability. Three-dimensional crack growth analysis of a blisk was also included proving that present research could benefit structural crack propagation analysis and damage tolerance design in engineering application.关键词：Damage tolerance;Crack growth;Engineering application
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- 983
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发布时间：2022-09-22
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