最新刊期
期 5 ， 2015
- 摘要：For reducing the influence of truncation error on the accuracy of time domain averaging（ TDA） induced by noninteger-period sampling,an improved algorithm of TDA based on fractional delay filtering（ FDF） is presented.On the basis of analyzing the disadvantages of current methods of TDA and the characteristics of FDF,a presently improved method of signal truncation was used in the method to avoid the accumulation of truncation error and obtain a delay factor on each of the truncated signals,the reconstruction and resample for the truncated signals were implemented with FDF,and finally the arithmetic mean were computed after all of the truncated signals were added.The theoretical analysis and experimental results demonstrate that the method which fully makes using of the advantages of FDF on the change of delay factor,apparently reduces the truncation error of signals with non-integer-period sampling,and could obviously improve the accuracy of TDA without key-phase signal.关键词：Fractional delay filtering;Time domain averaging;Truncation error;No key-phase signal
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发布时间：2022-09-22 - 摘要：Simplified mechanical model of FPB isolated bridges was established,the response amplitude was calculated used mode superposition method.The accuracy of results was verified by finite element simulation based on SAP2000.It was considered that the response amplitude agreed well with that of finite element simulation.Under the action of El Centro seismic wave,the results can meet engineering precision requirements basically.The response of girder and pier were mainly influenced by the isolated mode and second mode.关键词：Isolated bridges;Friction pendulum bearing;Mechanical model;Dynamic Analysis;Finite element simulation
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发布时间：2022-09-22 - 摘要：Aiming at the deficiency of the analysis of single channel signal EMD and dual channel signal traditional full vector spectrum analysis,this paper presents the full vector spectrum extraction based on EMD.The method of vibration signals collected from the same cross section of the two perpendicular on the sensor,then use EMD on each signal respectively,so that the two signals are decomposed into several IMF components.By the fusion of the IMF component,we can get the full vector spectrum based on obtained EMD.The simulation results show that,the method of obtaining fault characteristics is more comprehensive,accurate.The analysis results of bearing fault vibration signals of TRT generating units in a power rating of3000 KW,further shows the feasibility and effectiveness of the method.关键词：Empirical mode decomposition;Full vector spectrum;TRT generator;Fault diagnosis;Homologous information fusion;Sliding bearing
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发布时间：2022-09-22 - 摘要：In thin hydraulic pipes,the interaction between acoustic field in the fluid and structural wave field may results in more energy loss.In order to make clear the energy loss mechanism of this kind of cylindrical pipe,an analytic study on the acousto-structural coupling of a thin cylindrical pipe is carried out using the impedance-mobility approach（ IMA） in this work.Coupled equations for describing such acousto-structural coupling are derived from the wave equation and the dynamic equation of a cylindrical shell.In deriving the dynamic equation of a cylindrical shell,wave propagation involving distortion of the cross section is considered,which is very different from general researches about hydraulic vibration.In order to validate the IMA model developed,the acousto-structural response of a cylindrical pipe filled with air is calculated using IMA and FEA,respectively,which reveals the good agreement between IMA and FEA results.关键词：Acousto-structural coupling;Impedance-mobility approach;Hydraulic pipes
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发布时间：2022-09-22 - 摘要：Aiming at feature identification of weak signal for rolling bearing fault,an adaptive redundant lifting scheme packet（ ARLSP） diagnostic method of undecimated operation was proposed to solve the faults distortion that caused by traditional wavelet packet or lifting wavelet transform using sample operation.ARLSP was based on the principle of lifting scheme.Initial undecimated prediction and update operator were calculated by Lagrange interpolating subdivision,and then constructed an ARLSP decomposition and reconstruction algorithm.Simulation signals were tried out by denoising and anti frequency aliasing,results show that ARLSP method was superior to the traditional wavelet packet in denoising capabilities,and there are no frequency aliasing.Moreover,taking an experiment on an asynchronous motor,the vibration signals of the rolling bearings 6205 under conditions of no fault,the inner ring fault,outer ring fault and rolling fault were measured.ARLSP method has been successfully used to extract characteristic frequency and frequency multiplication for various faults,and has got a higher diagnostic accuracy than traditional wavelet packet.关键词：Rolling bearing;Adaptive redundant lifting scheme packet;Fault diagnostic;Traditional wavelet packet;Frequency aliasing
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发布时间：2022-09-22 - 摘要：To analyze the present problems of the elastic-ring isolator,such as the unideal damping effect,the unadjustable damping and so on,the piezoelectric shunt damping technique was adopted to study the vibration control performance of the elastic ring.Using piezoelectric film as a substitute for the damping material of the elastic-ring isolator,the elastic-ring piezoelectric shunt damping isolator was designed.Moreover,shunt circuit was designed which was based on the gyrators and the piezoelectric shunt damping system electromechanical coupling model was established to study the method of optimizing parameters of the shunt circuit.Furthermore,the optimal parameters were determined.Finally,the vibration control performance of the piezoelectric shunt damping system was experimentally analyzed.Experimental results show that the vibration of the structure can be reduced by 9 d B.关键词：Piezoelectric shunt damping;Elastic ring;Isolator;Shunt circuit
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发布时间：2022-09-22 - 摘要：In the traditional design method of heavy duty hydrostatic rotary table,the influence of centrifugal force has not been considered in the calculation of bearing capacity of fan-shaped hydrostatic thrust bearing supplied with constant oil flow and the adopted simplified calculation method is lack of experimental verification.In this paper,a new analytical calculation method of bearing capacity of fan-shaped hydrostatic thrust bearing supplied with constant oil flow is presented in which the influence of centrifugal force is considered.The experimental system of heavy duty hydrostatic rotary table is designed and established,and corresponding experiment is carried out.The experimental results have a good fitness with analytical calculated ones,which has verified the validity of the proposed calculation method.The new method provides a theoretical basis for the design and calculation of the fan-shaped hydrostatic thrust bearing supplied with constant oil flow.关键词：Constant oil flow;Hydrostatic thrust bearing;Heavy duty hydrostatic rotary table;Experimental system
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发布时间：2022-09-22 - 摘要：Based on years’ experience in fracture toughness tests,the matters need attention for KRcurve and fracture toughness determination using thin compact tension（ C（ T）） specimen were studied.The KRcurve and fracture toughness of LY12 CZ alloy and friction stir welded joints were determined according to proposed test method.The microstructures of FSW joint were also observed utilizing metalloscope.The test result demonstrates that the fracture toughness of friction stir welded LY12 CZ alloy is higher than that of the parent alloy,because the weld nugget presents fine recrystallized structure.It is also found that the fracture toughnesses with crack perpendicular to rolling direction are higher than those with crack parallel to rolling direction for both welded and parent alloy.In addition,the test result indicates that the fracture toughness of C（ T） specimen is related to inplane dimension,and that the fracture toughness increases with the increase of in-plane dimension.关键词：LY12CZ alloy;KRcurve;Fracture toughness;Friction stir weld;Compact tension specimen
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发布时间：2022-09-22 - 摘要：In order to simulate the actual cutting situation accurately in measuring stiffness of Numerical Control（ NC）machine tool,a novel full loading method is presented.It is based on the changing of the cutting position as the cutting tool is subject to the action of full load of force and torque under machining process.According to distributing principle of cutting force,a full loading device has been developed through the coordinate transformation of force-bearing point and its direction.The ratio between several forces in various directions is verified by loading tests.Moreover,the device has been applied to stiffness distribution test of NC turning centers,and the displacement of every measured point is obtained when the cutting tool is at different positions.The text results provide referencing data for evaluating and improving construction of machine tool and find application in the prediction and modification of design scheme.关键词：NC Turing Centers;Automatic shifting;Full loading device simulation;Stiffness distribution
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发布时间：2022-09-22 - 摘要：A new subsection-loading method has been used for solving question that was taken for aircraft structure cracking growth testing（ CGT） in a long time.Based on technology of low load cut-off,the random loading spectrum used in CGT,associated with the stress intensity factor in crack tip of specimens,was investigated.Furthermore,Testing verification of panel specimen has been completed.The testing result showed that pre-simplification agrees with subsection of the random loading spectrum,and application of the method can reduce the time of CGT reliably（ time reducing by 27% in the testing）.Finally,it can be concluded that the method can directly be applied for CGT of fuselage panel and other aircraft structures.关键词：Technology of low cut-off;Subsection-loading method;Stress intensity factor;Typical panel
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发布时间：2022-09-22 - 摘要：Having a unique physical characteristics and stable semiconductor properties,silicon carbide（ Si C） monocrystal wafer has been widely used in integrated circuits,space optics and other fields.In manufacturing process of Si C monocrystal wafer,cutting is primary key process,which the cutting costs accounts for more than 50% of the whole wafer processing costs.In this paper,the datum and relevant literature of domestic and foreign were reviewed to,the current research status of Si C cutting technology,especially cutting with wire saw,and cutting equipment were studied.Moreover,the existing problems in Si C cut by wire saw and in cutting equipment was analyzed.It is proposed that the future researching direction of Si C wafer cutting technology by wire saw.关键词：SiC mono-crystal wafer;Diamond wire saw;Cutting technology with wire saw;Present researching status
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发布时间：2022-09-22 - 摘要：A low cycle fatigue life prediction method for single crystal nickel-base superalloys at high temperature is presented,and the method can consider the effect of average stress,strain ratio and crystal orientation on fatigue life.Firstly,a fatigue life prediction model is established to predict fatigue life of single crystal nickel-base superalloys in the [001]and [111]crystal orientations.The model considers the effect of mean stress and strain ratio on fatigue life.Then,to consider the effect of crystal orientation of single crystal nickel based superalloys on fatigue life,the relationships of fatigue parameters between[001].[111] and other different crystal orientations are given by an orientation function.Finally,the fatigue life prediction method of single crystal nickel based superalloys for other crystal orientations is proposed by using fatigue parameters of the[001]and [111]crystal orientations.The method is validated using low cycle fatigue test data of DD3 and PWA1840 nickelbase single crystal superalloy at high temperature,and the results show that the proposed method is acceptable.关键词：Nickel-based superalloys;Crystal orientation;Low-cycle fatigue;Life prediction;High temperature fatigue
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发布时间：2022-09-22 - 摘要：The deformation of static bending was analyzed for uniform beam by the boundary element method.Non-uniform beam was combined with multiple uniform beams by method of system rigid combination without coordinate transformation.Stiffness equation of flexure hinges with straight circular was proposed.A micro rotary mechanism with symmetric drive as well as guiding and transformation was designed based on drive and guiding principles of flexure hinges with straight circular,which is able to make linear motion displacement into rotary displacement,the analysis of degree of freedom about it was given.The analysis of statics with micro rotary mechanism was finished by the finite element method,and the analysis results show that the largest simulation stress of the mechanism is much less than the material allowable stress.The dynamics-free-modal with micro rotary mechanism was analyzed by the finite element,and experiment of the modal analysis was finished,the error between the experimental results and the finite element is less than 6.25%,the analysis results prove that the mechanism has a high the First six order natural frequency and it will not cause resonance in the movement process of the precision rotary system with macro /micro dual-drive.The analysis of performance and experiment shows that micro rotary mechanism has the feature of single-degreefreedom-drive and high reliability,as well as good performance of modal.关键词：The boundary element method;Straight circular;Flexible hinges;Micro rotary mechanism;Modal analysis
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发布时间：2022-09-22 - 摘要：Fatigue is a phenomenon of high uncertainty,especially for components with multiple damage sites.The fatigue life（ either mean value or probability distribution of the random variable） of a complex component with multiple damage sites is not equal to that of a simple component with only one damage site.A multi-site damage component is a series system with many weak links（ damage sites） in probability sense.A probabilistic fatigue life prediction model for multi-site damage component is presented based on a systematic thought,as well as the order statistics and extreme statistics concept.Such developed model can naturally reflect the effect of the dependence among different damage sites.Experimental result and the example on multi-site damage component fatigue life prediction shows that the fatigue life of a multi-site damage component is much lower than that of a single site damage component.关键词：Multi-site damage component;Probabilistic fatigue life;Failure dependence;Stress distribution;Conditional life distribution
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发布时间：2022-09-22 - 摘要：Depending on the form of mechanism,the hinge wear and rod end bearing wear are considered respectively,and the self-lubricating rod end bearing wear model are established.Then the over-center locking reliability analysis model of four bar linkage mechanism is built under the "effective lever length theory"and "continuous contact model"hypothesis,besides,a reliability analysis method of over-center locking considering the initial clearance and wear is presented.The results show that the failure probability of mechanism over-center locking will rapidly increase after a certain number of cycles; the reliability of mechanism over-center locking will be significantly improved by using self-lubricating rod end spherical plain bearing.关键词：Rod end spherical plain bearing;Over-center locking;Wear;Clearance;Reliability
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发布时间：2022-09-22 - 摘要：Based on the coal rock cutting theory,simulated the load characteristic of the roller in the process of during coal rock; with the flexible-body dynamics as the theoretical basis to establish rigid-flexible coupling model of cutting unit,simulate the process of height adjustment by ADAMS and get the load response of link point; used Workbench to get the stress distribution of ranging arm when the link point force is maximum during the process of height adjustment; with linear cumulative damage rule as the theoretical basis,used Workbench to estimate the fatigue life of the ranging arm to verify the results of the reliability analysis and load response analysis.This paper provides a new method to research on dynamic characteristic and reliability of shearer cutting unit.关键词：Shearer cutting unit;Load characteristic;Dynamic response;Reliability
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发布时间：2022-09-22 - 摘要：It is the most important inspection index the deflection value of the gantry crane girder under rated load in the overall test.For large tonnage gantry crane in the overall test,prepared the experimental weight is often very difficult at the site,or even impossible perform test.In the text,it is deduced the girder deflection curve equation under the considering effects of the leg bending moment to the girder deflection When the concentrated load is applied to the position of the girder midspan.The girder deflection values can be obtained under three-small-loads at the girder midspan,and the coefficients of gantry frame girder flexural equation can be obtained.In this way,the deflection of the large tonnage gantry crane is predicted through the data of the three-small-loads method in the test.The three-small-loads method provides a practical and effective method for the prediction of the girder deflection of large tonnage gantry structure.关键词：Gantry crane;Rigid legs;Prediction deflection;Load test;Structure stiffness
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发布时间：2022-09-22 - 摘要：As a type of typical cellular foams,the macro-mechanical performances of rubber foams are mainly determined by its micro-structure and cell material properties.In the work reported here,several two dimensional（ 2D） finite element（ FE）models having regularly and randomly arranged elliptical and circular cells were constructed.The effects of cell shapes,cell distributing,and porosities on the hyperelastic large compressive deformations of rubber foams were explored.Obtained FE analysis results show that the compressive stress-strain curves of rubber foams present three deforming regions.The compressive stress-strain curves of circular cell models have longer plateau stage than those of elliptical cell models,and circular cell models have more steady mechanical performances than elliptical cell models do.If worked as shockproof cushions,circular cell structures are thus better than elliptical cell structures.关键词：Rubber foams;Cell structure;Compressive behavior;Micro-mechanical model;FEM
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发布时间：2022-09-22 - 摘要：When angular contact ball bearings match together,due to high demand of manufacturing and installation precision,only increasing the number of angular contact ball bearings to increase the radial bearing capacity has great limitations.Therefore,it was considered that using heterogeneous rolling bearing match to increase the radial bearing capacity of bearing match has obvious advantages.Structure characteristics and mechanical properties of the existing angular contact ball bearing match way has been analyzed and compared,and then the applicability of them has been explained.For the existence of the high accuracy requirement and the low radial load capacity,a way of heterogeneous rolling bearing match way was put forward.Its characteristic is to use deep groove ball bearings or cylindrical roller bearing to bear radial load bearing,and angular contact ball bearing to bear axial load.Then,the formula was derived for calculating the life of a heterogeneous rolling bearing match way.At the same time the life calculation formula of"QBC"angular contact ball bearing was deduced.Comparison of the two above show that heterogeneous rolling bearing match way obviously improves the radial bearing capacity,obviously prolong service life,and the demand of bearing manufacturing and installation accuracy is low.The results have been applied to an import petrochemical plant methylamine pumps.After calculation,heterogeneous rolling bearing match way increases by 52.5%.关键词：Angular contact ball bearing;Service life;Match way
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发布时间：2022-09-22 - 摘要：Using composite laminates with a bolt-filled hole were proposed to study interlaminar stress distribution of laminates joints hole-edge,and a 3D finite element model with a zero-thickness cohesive element was established for solving holeedge interlaminar stress of laminated plate in tension.The results show that interlaminar normal stress distribution along the hole mainly affected by the bolt-clamping force,under the same bolt-clamping force,interlaminar normal stress value ranges is close;The interlaminar shear stress impact both by the bolt-clamping force and interface ply parameters,such as interlaminar shear stress of [-45 /90] and [0 /-45] interface is larger than others; Interlaminar normal stress caused by bolt-clamping force was mainly compressive stress,and it is beneficial for the interlaminar strength,but interlaminar shear stress generated in the same time is not help to improve the interlaminar strength,therefore,a reasonable clamping force can enhance the interlaminar strength for bolt composite joints.关键词：Composite laminated plate;Interlaminar stress;Filled-hole tension;Bolt-clamping force;Delamination;Cohesive zone model
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发布时间：2022-09-22 - 摘要：A performance evaluation technology was studied for the seismic performance evaluation of nuclear safety Class II main feed-water control valve based on the ASME Code and finite element analysis platform（ Femap + NX Nastran）.First,we proposed an analysis model for the vertical control valve,and the risk assessment and improvement methods for the structural characteristics of vertical control valve were studied.Then we conducted a numerical model for a control valve and compared the simulation data with those obtained from experimental test.These two showed good agreement.Finally,the seismic performance evaluation of a main feed-water control valve was performed under the combination of the seismic load and design load.The simulated relative error of inner stresses at typical site is less than 5% compared with that obtained by using empirical formula.The simulated data shows that the designed valve fulfills the design requirement for its first order frequency is bigger than 33 HZ,and the maximum stresses are within the allowable range under various load cases.关键词：FEM;Nuclear safety Class II;Feed-water control valve;Performance evaluation
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发布时间：2022-09-22 - 摘要：In this paper similarities and differences in Bearing Capacity Calculation of Aviation Bevel Gears（ HB / Z89.1 HB / Z89.4-85） and Rating the Pitting Resistance and Bending Strength of Generated Straight Bevel,Zerol Bevel and Spiral Bevel Gear Teeth（ ANSI / AGMA 2003-B97） were analyzed and compared.It was compared in scope,calculation principle,fundamental rating formulas,correction factors and calculation example such several aspects.The strength evaluation value was introduced to make it easy for comparison.The two standards have their own characteristics according to the research results.The former’s correction factors are considered more comprehensive,and the correction factors are subject to theoretical calculation; the latter’s calculation is simple and the correction factors are mainly based on experience formula and test data.The contact strength evaluation value of the former is larger than the latter,while the bending strength evaluation value is smaller.At last the conclusion is the former’s strength rating is more conservative.
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发布时间：2022-09-22 - 摘要：By use of the finite element software Hypermesh and LS-DYNA,the processes were respectively simulated of urban rail vehicle head car,with and without anti-climbing energy absorption device,impacting the fixed rigid wall face to face at the speed of 12.25 km / h and 18 km / h.Based on the obtained data,the crashworthiness of urban rail vehicle head-car body and performance of its energy absorption device were evaluated.Using the response surface methodology,the factors influencing anticlimbing ability of anti-climber were also studied.The results show that,when the crash speed is respectively at 12.25 km / h and18 km / h,the energy absorption device would absorb impact energy before car body structure by plastic deformation,protecting the car body without and with only a little plastic deformation.In addition,when the total height and tooth thickness of anti-climber are fixed,its anti-climbing ability would decrease as the tooth height and angle increases,and the tooth height has more influence than the angle.关键词：Urban rail vehicle;Crash;Simulation;Crashworthiness;Anti-climbing ability
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发布时间：2022-09-22 - 摘要：Ball screw pairs of high static stiffness is to guarantee the positioning accuracy and speed of ball screw pair a good ability to adapt the key.Considering the influence of deformation on nut assembly static axial stiffness nut bearing radial,based on simplified model on the analysis of simplified nut assembly static axial stiffness calculation formula.Through the example,will consider the simplified calculation of the pair radial deformation and the traditional ball screw calculation results and the experimental test results for comparison,proved that does not consider the effect of deformation on the ball screw pairs nut assembly static axial stiffness nut bearing radial calculation to the static stiffness is not comprehensive.The research results laid a foundation for the accurate analysis and optimal design of ball screw.关键词：Ball Screw;Static axial stiffness;Radial deformation;Nut union
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发布时间：2022-09-22 - 摘要：To describe the phenomenon of the stress generation and stress relaxation occurring simultaneously in the process of whisker growth,a UMAT subroutine in Abaqus is developed to solve the elasto-plastic creep constitutive model by means of the return-mapping algorithm.The finite element simulations show that,compared with the elasto-plastic model in Abaqus,the elasto-plastic creep constitutive model characterizes the stress relaxation of material better.Using this subroutine,we calculate the change of stress in a specimen of Pb-free solder.In terms of the change of stress,the whisker growth rate is evaluated.And the effect of the grain size on the whisker growth rate is discussed.关键词：Sn whisker;Stress relaxation;Return-mapping algorithm;Elasto-plastic creep constitutive model
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发布时间：2022-09-22 - 摘要：This paper studies linear variable thickness circular aperture concave template theory of stiffness and strength calculation.First,set up mechanical model:Template for circular concave,outside the perimeter fixed; center has a round hole,inside the perimeter free,outside under uniformly distributed vertical load.Secondly,the establishment of mathematical model:Derivation of concave template in the axisymmetric condition,ordinary differential equation with variable coefficients of elastic curved surface,and gives the mathematical expressions of boundary conditions.Again,in view of the differential equation boundary value problem,the displacement method and the Matlab algorithm,it is concluded that the deflection of concave template function,and establish the stiffness calculation condition of concave template.Then,determine the concave template on the bending moment and the maximum bending moment and stress,so as to establish a concave template strength calculation conditions.Finally,numerical examples.This paper presents the function solutions,to change law of control concave template section variable parameters.In this way,not only highlight the interdependent relationship between the quantity of each,and optimization,and discussion and application.The result is suitable for uniform,continuous,isotropic material artifacts.Because in the process of calculation and data processing with error,so the formula is similar.关键词：Linear variable thickness;Circular concave template;Stiffness computation;Strength calculation
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发布时间：2022-09-22 - 摘要：In order to enhance the computational accuracy of the roll flattening radius of the hot strip mills,the explicit algorithm of the roll flattening radius was put forward.Compared with the traditional Hitchcock equation,the iteration is omitted in the calculation process.The computational accuracy of the roll flattening radius automatic control model can be enhanced in hot strip rolling.Meanwhile,the response speed of the roll flattening radius control system can be improved too.Taken the 500 mm strip 9 hot continuous rolling strip mills for example,the roll flattening radius is calculated.The computational accuracy can enhance 2.14% at most.关键词：Flattened radius of roller;Explicit algorithm;Iterative algorithm;Rolling
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发布时间：2022-09-22 - 摘要：Based on the torsion beam rear axle,the parameters of entire vehicle are analyzed by ADAMS.The result show that the rear axle load is the most significant factor for vertical force amplitude at wheel center.The relationship between vertical force amplitude and displacement amplitude at wheel center are analyzed by Hyper Works.The result show that that the rear axle load is the most significant factor for displacement amplitude at wheel center.By summarizing the existed fatigue test examples for torsion beam rear axle,the relationship is established mathematically between rear axle load and the displacement of torsion beam rear axle.According to the above analysis,the general fatigue test specification for torsion beam rear axles is established.The effectiveness of the new test specification is verified by comparing with old test specification.关键词：Torsion beam rear axle;Durability test;Rear axle load;Vertical force at wheel center;Displacement at wheel center;Test Specification
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发布时间：2022-09-22 - 摘要：Base on six component test system,the load spectrum of a certain type of car were obtained in skid pad.As the input data,the fatigue of the twist beam was analyzed by the use of multiple computer aided engineering（ CAE） as finite element method,Multi-body dynamics and fatigue analysis.The risk of the cracking position was predicted and contrasted with the road test.The results show that the predicted damage position based on the measured load spectrum was in good consistence with the road test.For the cracking risk position,corresponding optimized scheme was presented,and the damage distribution after optimization was given.The optimized scheme effectively reduced the risk of cracking of the original scheme,and the cracking problem of the twist beam was solved.关键词：Twist beam;Fatigue analysis;Durability;Load spectrum
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发布时间：2022-09-22 - 摘要：Vehicle road simulation test should reflect the vehicle service loads actually,traditional load spectrum compilation methods were unable to meet the requirements of road simulation test.Therefore it is necessary to apply a load spectrum compiling method which can retain characteristic of the service load.In this paper,Several kinds of load spectrum compiling methods are compared and analysized,and time correlated fatigue analysis with damage editing method is considered to be the most effective,because it can maintain all the properties of service load（ amplitude,frequency,loading sequence and multi-channel phase） over an accelerated time.Based on proving ground collected loading spectrum of the test vehicle,this method was applied to generate test spectrum.The effectiveness and validity of the accelerated spectrum were verified theoretically from amplitude domain and frequency domain.The results have shown that the test time of the accelerated spectrum was significantly reduced while simultaneously the damage value and properties of the original spectrum were well maintained.Finally,vehicle bench durability test was conducted,and the same test results have been acquired as those of field test.The validness of this methodology was demonstrated.关键词：Road Simulation Test;Time Correlated Fatigue Analysis with Damage Editing Method;Load spectrum compilation
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发布时间：2022-09-22 - 摘要：The test method of fuselage panel subjected to internal pressure load is an important technique for aircraft structure strength research.The constraint simulation technique for the curved and straight boundaries of fuselage panel was studied based on boundary requirements.A test method using "D"jig to simulate the straight boundary conditions and airproof end-plate to simulate the curved boundary conditions of fuselage panels were proposed.A test panel and a set of fixtures were designed and manufactured,and validation tests were conducted.Measured stresses in test are reasonably distributed and are consistent with theoretic result.The proposed test method is proven to be proper and valid,and it provides reference for configuration-selection tests of fuselage panel subjected to internal pressure load.
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发布时间：2022-09-22 - 摘要：In order to analyze the change law of stress of aluminum chaff in the process of rolling waves,and the reasons of the eccentric circular to get the accurate wave of radiating corrugated ribbon,the model of bilinear isotropic harden was established to simulate the process of rolling wave in the Ansys Workbench.The result of rolling wave Aluminum chaff was verified on the machine of rolling wave.The results show that the curve of stress is the form of wave which correspond to the wave of aluminum chaff; The residual stress of aluminum chaff reduce along the arc of peak,while the reduce is asymmetric distribution on both sides,which is the reason of the eccentric circular; due to the meshing movement of tool,the plastic strain increased to the maximum in stages; the model of actual rolling waves match with the the theory modal,which verify the correctness of the analytical method.关键词：Radiating corrugated ribbon;Process of rolling wave;Aluminum chaff;Residual stress;Plastic strain
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发布时间：2022-09-22 - 摘要：As one of the essential criteria of assessment to welding toughness,CTOD（ Crack tip opening displacement） is widely applied in engineering.The research on critical CTOD of big thickness and high strength steels has been a hot issue,therefore the theoretical research in China lags behind its overseas.The present paper takes the single edge fatigue precrack of CTOD specimen as a flaw based on the technical route of the British Standard 7910-2005,which is "Guide to methods for assessing the acceptability of flaws in metallic structures".In the meanwhile,make the grading assessments of the HAZ of the60 mm thick EQ70 steel welded joints,combining the results of the CTOD tests.The CGHAZ microstructures of EQ70 steel welded joints has been analyzed by SEM.The assessments on welded joints of EQ70 show that the CTOD values are in the acceptable range.And there are some fine microstructures good for the toughness of the welded joint.This method provides a useful guidance in researches of critical CTOD.关键词：BS7910;FAD;EQ70;Microstructure;Critical CTOD
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发布时间：2022-09-22 - 摘要：a combination method of simulation and test data to solve the material parameters was raised,with the certain material parameters a new type of connecting rod of disconnector was analyzed.Material‘s Young modulus and Poisson’s ratio was obtained by using the existing connecting rod of disconnector.The model of new type of connecting rod of disconnector was made by the software of Solidworks.The finite element software of Ansys Workbench was used to carry out linear static structural analysis.The simulation result provides a theoretical basis for design and analysis new type of connecting rod of disconnector.关键词：Material parameters;Disconnector;Finite element;Ansys workbench;Linear static structural analysis
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发布时间：2022-09-22 - 摘要：Spatial 3-rod structure is one of the bus basic structures.Effects of the topological locations of angle brackets on the rigidity and strength of spatial 3-rod structure of bus body were discussed.The calculation by finite element calculation and experimental analysis showed that:1The structural rigidity and strength under bending loads were enhanced remarkably when the plane of angle bracket was parallel to the bending loads direction.2The structural rigidity and strength under torsion loads were enhanced remarkably when angle bracket was added at the top side of the joint between the load-carrying rod and side rod.3The most effective way to enhance the structural rigidity and strength and improve its high stress distribution was adding one angle bracket at the top side of the joint between the load-carrying rod and side rod and another angle bracket at the lateral side of the joint between the load-carrying rod and master rod（ the tenth angle bracket location）.This paper provided a valuable reference to the design of agricultural machinery and engineering structures,besides the bus body joints design.关键词：Bus body;Joint;Spatial 3-rod structure
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发布时间：2022-09-22
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