最新刊期
期 1 ， 2017
- 摘要：In order to study the influence of shearer traction speed on its dynamic characteristics,using the three-axis force of pick as the description of cutting incentive of shearer pick,Hertz contact theory was used to describe shearer’s smooth boot brace stiffness and damping. Nonlinear model of meshing gear with the clearance was used to describe brace stiffness and damping of shearer guide boot and the pin rows. 7-DOF dynamic model of shearer was established according to Lagrange ’s equations. Vibration characteristics of shearer under different traction speed was solved by numerical methods. The results show that the increasing of speed have great influence on the vibration displacement of back-end drum,have little effect on the fuselage,and have significant influence on Y axis vibration angle of the fuselage.关键词：Shearer;Nonlinear;Vibration;Clearance dynamics
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发布时间：2022-09-22 - 摘要：Several traditional gear diagnosis methods are reviewed. The narrow band demodulation method is often accompanied with low-frequency interference and the resonance demodulation technique is limited in amplitude demodulation.According to the pros and cons of the traditional methods,the resonance band amplitude-phase demodulation technique was proposed for local gear fault detection to compensate the current gear diagnosis methods. It’s a method that taking the resonance frequency as carrier frequency instead of meshing harmonics,hence the low-frequency interference can be suppressed. Amplitude demodulation incorporated with phase demodulation will make the diagnosis more accurate. In this scheme,the fast kurtogram is firstly used to find out the resonance band. Then take the resonance frequency as carrier frequency and implement the resonance band amplitude-phase demodulation program gets both the amplitude and phase modulation functions,which would indicate the gear fault. Simulation and experiment studies indicated that the proposed method is an effective tool for early gear tooth cracking fault detection.关键词：Early gear tooth cracking fault;Narrow band demodulation;Resonance demodulation;Resonance band amplitude-phase demodulation;Fast kurtogram
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发布时间：2022-09-22 - 摘要：Analyzing the working principle of Hydro-mechanical Continuously Variable Transmission（ HMCVT）,and studying a HMCVT for water-dry dual-purpose high-power tractor. To design a scheme for this HMCVT accord to the complex working requirements of the water-dry dual-purpose tractor,and then to make simulation analysis of the dynamic characteristic based on the MATLAB software platform. The simulation results show that the water-dry dual-use large power tractor equipped with the HMCVT can work when runs in the water-dry land,realizing the continuous velocity.关键词：Tractor;Hydraulic machinery continuously variable transmission;Dynamic characteristics;The continuous velocity
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发布时间：2022-09-22 - 摘要：In order to study the stereo garage frame structure stability and displacement of frame under earthquake load response,combined with the theory of modal analysis and extraction method,using ANSYS finite element software to frame modal calculation,and extract the natural frequencies and mode shapes of order 8 of its former. The EI Centro earthquake wave which is similar to the seismic requirements has been chosen for simulated seismic wave which is used to analyze the deformation of the frame. The results show that the natural frequency of the frame is lower,and the resonance phenomenon may occur due to the external load. The frame natural frequency should be avoided similar to the external load vibration frequency. The displacement response of each frame node under the action of simulating seismic waves is between- 30 mm 35 mm,and the value is far less than the material yield limit. That suggests the seismic performance of three-dimensional parking spaces can meet the requirements.关键词：Stereo garage;ANSYS;Seismic performance;Modal analysis
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发布时间：2022-09-22 - 摘要：Based on the mechanical force model of the bucket on the working device of loader,the problem of the dynamic loading test was analyzed. The testing method considering pin-shaft lateral dynamic force was put forward,and the 3D forces in horizontal,vertical and lateral direction of the loader working device were accurately measured. Without changing the loading characteristics of the working device,the pin-shaft dynamic force test system was established with the pin-shaft sensor design and the bucket structure modification. Primary soil containing granular iron ore was chosen as the shovel loading operation case,and the dynamic forces in three directions of the pin-shaft linking the arm and the bucket were acquired through the shovel loading test. The results show that: the dynamic testing method and the system could accurately obtain the dynamic loads of three directions of the pin-shaft; the dynamic loads of the three directions measured by the pin-shaft sensors are closely related to the loading process; the dynamic loads of the lateral force of the loader working device with the change of loading process were obtained firstly. It has important guiding roles for the study on the mechanical characteristics of the loader working device,the acquisition of the load spectrum and the prediction of fatigue life.关键词：Loader;Pin-shaft;Dynamic loads;Lateral force;Experimental research
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发布时间：2022-09-22 - 摘要：There will be different loads along the structure surface when it impacts on the water,which has an important effect on the safety of the capsule structure and the people inside. So the research of water impact has a practical significance in the field of aerospace and military. Base on wedge and arc body model,the test of free fall on the water has been investigated on different situations. Firstly the parameter of PVDF is calibrated in the static and dynamic state,using which the distribution of surface pressure is obtained. Then different situations of the experiment are simulated by LS-DYNA and the test pressures are proved further. The pressures are analyzed by different factors. Finally base on the similarity criteria,the impact response of real aircraft structure are obtained by the test data,which has a valuable reference for the design of structure.关键词：Water impact;Polyvinylidene fluoride（PVDF）;Calibration;Pressure;Similarity criteria
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发布时间：2022-09-22 - 摘要：In order to study the mechanical and load properties of idler shaft on rocker arm shearer under complicated conditions,used the shaft sensor to test the load of idler shaft on rocker arm under different conditions,and through the wireless module to store and transmit the real-time data,with some test data curves in Z and Y direction obtained. The analysis results show that the load of idler shaft is the largest when coal winning machine under the oblique cutting condition,the largest load of 33. 38 kN in Z direction,the largest load of 35. 60 kN in Y direction,and thoughtout the process,the load in Y direction always larger than Z direction. The results of the study provide a new way for the idler shaft load test and data support for the coal-rock identification method and the fault monitoring on rocker arm shearer,also has important guiding and significance for coal winning machine parts design and optimization.关键词：Coal cutter;Idler shaft;Strain signal;Characteristics of dynamic loading
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发布时间：2022-09-22 - 摘要：The application of laminated metal sheet in the numerical control busbar blanking process is increasingly wide. In this paper,the blanking process of laminated copper sheet is studied to improve edge quality of parts in blanking laminated metal sheet. Compare single metal sheet blanking process,laminated metal sheet is different. Laminated copper sheet blanking experiments are conducted in the busbar processing machine’s blanking station and taken some approach that through DAQ to collect pressure,displacement sensor test data in blanking laminated copper sheet under different blanking clearance. Blanking force variation trend with displacement is obtained,and relationship between aperture size,deformation collapse height and blanking displacement is also acquired. Data above are analyzed and compared. Studies have shown that blanking force increases with decreasing blanking clearance and deformation collapse height and aperture size accuracy have a lot to do with the layer number of the place of laminated sheet. Compared single metal sheet with laminated metal sheet blanking process,influence factors are more and problems are more complicated which in blanking laminated metal sheet,quality of parts in blanking laminated metal sheet can be improved by controlling some environment which including blanking clearance and blank-holder force.关键词：Laminated copper sheet;Blanking experiment;Blanking clearance;Blanking quality
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发布时间：2022-09-22 - 摘要：The coal is the basic raw material for energy in China. It has strategic role in national economy,while the problems of roller surface adhesion,belt jitter,falling coal along return trip caused by coal freezing adhesion seriously restrict coal transportation in winter. Prior studies show that surface roughness has an important effect on freezing adhesion,in order to alleviate the freezing adhesive problems of coal by improving the material’s surface shape,our research group designed the freezing adhesive strength test device,under the certain frozen condition,freezing adhesive characteristics of six different roughness steel plates with moisture content 40% of the coal slime were tested. The results show that,the coal freezing adhesive strength with the change of roughness in W curve,appears minimum value when Ra= 9 10 μm,further suggest that appropriate surface roughness can reduce coal freezing adhesive strength. Thesis has guiding significance on mechanism research of freezing adhesion and other anti-freezing adhesive engineering fields.关键词：Coal;Freezing adhesion;Roughness;Steel plate
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发布时间：2022-09-22 - 摘要：Tailor Rolled Blank（ TRB） is an emerging steel rolling process to effectively produce lightweight vehicle components. It allows continuous metal thickness changes. Combining with the design method of body collision force transmission path and load flow reasonable distribution,optimization design and analysis of a SUV on critical parts structure was carried out based on the TRB technology,which have great effects on the vehicle body safety in side collision. Studies have shown that using the new TRB steel had caused the deformation of vehicle and the intrusion speed peak value of chest and pelvis reduced. The vehicle lightweight was cut down 5. 5kg,the number of automotive parts was reduced 5,while the crash safety was ensured.Accordingly,decreasing weld process,manufacturing procedure,and achieve the dual goals of crashworthiness and reduction.关键词：Tailor rolled blank;Collision force;Load flow;Critical parts;Optimization design;Reduction
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发布时间：2022-09-22 - 摘要：Based on first order reliability analysis method（ FORM）,concurrent subspace optimization（ CSSO） method was employed to research on the efficiency of reliability analysis of multidisciplinary coupled system. The precision and efficiency of the methods was discussed. The result shows that the reliability analysis method based on CSSO is more efficient than single level method.关键词：Multidisciplinary coupled system;Reliability analysis;Kriging approximation;CSSO
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发布时间：2022-09-22 -
POINT ESTIMATION OF THE PARAMETER OF GEOMETRIC DISTRIBUTION UNDER A PARTICULAR RANDOM CENSORING TEST
摘要：The MLE of geometric distribution are studied by ML method and EM algorithm under a particular random censoring test. The proof of existence and uniqueness of MLE and EM iterative formula of the parameter are given. The asymptotic variance of EM estimation is obtainde by Louis algorithm. Random simulation results show that the MLE and EM estimation are both fairly accurate,and make little difference.关键词：Random censoring test;Geometric distribution;Maximum likelihood estimation;EM algorithm;Asymptotic variance- 2
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发布时间：2022-09-22 - 摘要：Commercial vehicle plays an important role in economic development. It is important to investigate its safety design. In this paper,High strength steel was applied to the frontal impact safety design of a commercial cabin with the requirement of ensuring the survival space and not increasing body weight as well as material cost. Firstly the global sensitivity analysis was carried out to choose the prominent parts,then their material were changed into HSS,the optimization was conducted by employing NAGA- Ⅱ algorithm with their thickness chosen as design variables. The result shows that the cabin keeps its dynamic and static mechanical properties and its frontal impact safety is improved with the application of HSS,at the same time the body weight and material cost are both decreased.关键词：Commercial vehicle;Frontal impact safety;HSS;Optimal design
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发布时间：2022-09-22 - 摘要：Planes are the execution tools of coal plough,the work load directly affecting the planing capacity and production efficiency of the plow. In order to study the load characteristics,developing the coal plow load calculation program based on Matlab and VC,which can calculate the random load of planer at different positions according to the different simulating coal seam occurrence conditions; Planes at different positions were simulated and the strength verified based on ADAMS software. By analyzing the results indicate that : in the same cutting depth,the loads of planes at the different positions are random,in which load short broadsword’s means and standard deviations of the three load are minimum and the cutter force is relatively stable and uniform compared with other positions,followed by long broadsword,knife top and bottom knife; With increasing of planing depth,three forces of planes suffered have varying degrees increased,When the cutting depth exceeds a certain value,cutting resistance will be significantly increased; when the cutter spacing exceeds a certain transversal distance,cutting force increases sharply; In the working process,long and short waist by the maximum stresses are located in knife body thickness position transition connection and the knife body and the lamellar alloy head is embedded,main failure mode for the wear and fracture;the top and bottom knife knife connected with the knife base part chamfer can relax the stress concentration. Analysis results of load planer reliability and structure optimization design provides a theoretical basis for the study of dynamic.关键词：Plow;Planes at different positions;Load characteristic;Simulation study;Strength validation
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发布时间：2022-09-22 - 摘要：Based on finite element simulation,a 3D cell model subjected to low stress triaxiality,with a spherical void located in center was developed. The distribution rule of stress and strain was investigated,as well as the developing trend of volume of void and matrix. The analysis indicated that there are some limitations of the theories which regarded void volume fraction as damage parameter. Further research was carried out to verify the reliability of the fracture strain as element failure parameter by analyzing the results of uniaxial tension simulation and experiment. More investigation was conducted to analyze the void growth and material failure under low stress triaxiality by introducing critical equivalent plastic strain as failure criterion.关键词：Low stress triaxiality;Void behavior;Finite element simulation
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发布时间：2022-09-22 - 摘要：Aiming at overcoming the deficiency of balance of the Crank-group Driving Mechanism,utilize Mass moment substitution method to translate the equilibrium problem of inertia force of Crank-group Driving Mechanism into the additional mass moment of branch member（ connecting rod truss） in the adjacent cranks and the balance of two pair rod tree system that composed of all cranks in mechanism. The inertia force equilibrium condition for any Crank-group Mechanism can be listed directly by combining the formulas of the mass moment substitution formula of connecting rod truss and the inertia force balancing equation of arbitrary crank in the mechanism,then take Four-Cranks Mechanism as an example to simplify the equilibrium conditions that provide a theoretical basis for different structure form of cranks in the mechanism. Finally,use 3D modeling software Pro / E and dynamics analytic software ADAMS to verify the balance applicability for Crank-group Driving Mechanism.关键词：Crank-group Driving Mechanism;Mass moment substitution method;Two pair rod tree system;Complete balance of inertia force;Dynamic simulation
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发布时间：2022-09-22 - 摘要：For the demand of crashworthiness verification and certification of composite aircraft structures,a finite element model of fuselage section with waved-plates under cargo floor was suggested,and rigid simplified model of cargo was also developed. The crashworthiness performance was researched under 7 m / s vertical impact velocity. A comparative analysis of failure modes,acceleration response and energy-absorbing characteristics were given for composite fuselage section with and without cargo loading and the analysis were helpful to design and analysis of civil aircrafts. The results show that the energy absorbed by waved-plates is increased because of cargo loading,the acceleration of junction between outside seats and floor for fuselage section with cargo loading are lower than that of fuselage section without cargo loading,and there is no cascading crash scenario.关键词：Composite fuselage section;Crashworthiness;Cargo loading;Acceleration response;Energy-absorbing characteristics
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发布时间：2022-09-22 - 摘要：The surface roughness data of test-pieces with transverse profiles were firstly measured by a roughness profile measuring analyzer. With the help of the Fourier nonlinear approximation the measured data was used to form a roughness function which was superimposed to film thickness equation and a mixed thermal elastohydrodynamic lubrication model for the rolling bearing was then established. Based on the model,45 sets of numerical calculations were carried out by changing the roughness values under other conditions of the rolling bearing were fixed. Then the two quantitative relationships between the average oil film at the contact point and the roughness as well as the maximum subsurface principal stress and the roughness are respectively established through the regression analysis of the calculation results.关键词：Rolling bearing;Transverse rough texture;Film thickness;Subsurface stress
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发布时间：2022-09-22 - 摘要：Although the applications of the braided wire rope in electric power grid construction projects are universal,researches of domestic and foreign scholars are less. Based on the ellipse hypothesis and the forming research of the anti-twist braided wire rope,the space expansion graph was obtained by using the four-arcs method in drawing ellipse. According to the expansion graph,the relational expression between the rope length,braiding angle and the arc length was described. Considering the influence of physical characteristic parameters,the deformation of wire ropes was analyzed. Moreover,the expressions related to tension and axial force of strands corresponding to arbitrary arc section were deduced to establish the mechanical model of wire rope under axial load. In addition,take braided wire rope YS8 × 19 as an example,the total tension and tensile stress in arbitrary cross-section of the wire rope were given to further study for the mechanical properties of the anti-twist braided wire rope. Finally,the result obtained by numerical simulation is that the equivalent stresses of topical rope strands corresponding to the larger curvatures of the ellipse are larger.关键词：Anti-twist braided wire rope;Four-arcs method;Expansion graph;Mechanical model
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发布时间：2022-09-22 - 摘要：Design the shafting for photoelectric-equipment used in mobile-platform,mobile-platform. First,based on structure and assemble technicalof bearing put forward three kinds of structure for shafting,then,deduce the revise formulation for shafting aim at vibratory environment of mobile-platform,which was the theory basis for the shafting design in mobileplatform photo-electricity equipment.关键词：Mobile-platform;Photoelectric-equipment;Mechanical analysis;Bearing
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发布时间：2022-09-22 - 摘要：The equivalent flexural rigidity of a complex polygonal honeycomb structure is investigated in this study. The honeycomb is equivalent to a orthogonal anisotropic plate for calculating the deformation energy under uniform bending moment,and the deformation energy of each wall is summed,then the analytical expressions for the equivalent flexural stiffness of honeycomb structure were derived based on the energy equivalence principle. The angle and length of walls has a great influence on equivalent flexural stiffness,the changes of angle and length will lead to positive and negative changes of the coupling stiffness,the absolute value of flexural stiffness increases with the increase of the wall’s height and thickness. The validity of the present analysis is demonstrated by the inversion results obtained by the finite element method.关键词：Polygon;Honeycomb structure;Energy equivalence principle;Equivalent flexural stiffness
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发布时间：2022-09-22 -
BASED ON MATLAB AND EXCEL PROGRAMMING AND DEVELOPMENT THE NEW METHOD OF HEADING MACHINE CUTTING HEAD
摘要：Using MATLAB and EXCEL joint programming developed longitudinal roadheader cutting head design software,according to the existing conditions of tunneling face cutting head kinematics parameters necessary input through the cut,cut tooth can automatically generate the corresponding arrangement diagram,load curve and cutting diagram,obtain the cutting head shape,leaf number of head and pick arrangement parameters relationship mode and cutting power,cutting energy consumption ratio,cutting resistance and cutting area between,for the design and optimization of cutting head provides a new method. In the engineering objects of type EBZ220 machine for cutting head shape,leaf Numbers,and cutter tooth arrangement design and select the optimal scheme,the universality and simplicity of the software关键词：Roadheader;Cutting heads;Design ＆ Optimization;Cutting performance;New method- 4
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发布时间：2022-09-22 - 摘要：The roll stability directly affectsthe wheeled tractor security. Virtual prototyping technology was used to study wheeled tractor roll stability. The precise model of the wheeled tractor was established with 3D modeling software UG. Then the model was introduced into ADAMS / VIEW to simulate the static rollover stability test and the front wheels by unbalance force test of wheeled tractor. The tire force curves were analyzed to determine the tractor maximum rollover stability angle,which was used to measure the tractor roll stability. Finally the simulationresult was verified by real vehicle test. The deviation between real vehicle test results and simulation results was very small. Sothe virtual model was accurate and the simulation was reliable.Application of virtual prototyping technology can greatly improve the qualified rate of physical prototypes in wheeled tractor development process. The simulation can replace the real vehicle test in a certain extent and has practical value.关键词：Virtual prototyping technology;Wheeled tractors;Roll stability;Model;Simulation;Real vehicle test
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发布时间：2022-09-22 - 摘要：To study the stress of plastic helical gears in the new type car door lock under the working condition,establish the finite element model of helical gear mesh through ABAQUS,the contact process of plastic helical gears is simulated and analyzed based on nonlinear contact algorithm,and obtain the contact stress and bending stress of plastic helical gears. According to Lewis equation and gear Hertz stress theory to calculate the stress of the plastic helical gear meshing process,and compare with the finite element simulation results. The results verify the strength of plastic gears meet actual requirements,and point out the maximum contact stress in the normal engagement process appears in the double teeth meshing zone,the maximum bending stress appears in the three teeth meshing zone,gear prone to fatigue failure in those positions,propose advice to improve the strength of the gear teeth. The study prodives theory basis for the strength analysis of plastic gears.关键词：Plastic helical gear;Finite element analysis;Dynamic contact analysis;Gear strength
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发布时间：2022-09-22 - 摘要：For solving the inconsistence problem among existing theoretical solutions of the critical temperature for cylindrical thin-shell,in this paper,the theoretical solution of critical temperature was firstly deduced for a cylindrical thin-shell subjected to a uniform temperature rise based on Donnell equation. And then the numerical solutions of the flat-plate and the cylindrical shell were constructed separately. Lastly,comparison analysis between the theoretical solution and numerical solution was carried out,and the exact solution was obtained by introducing a modified coefficient. The study work will benefit to scientifically design related thin-shell structures in the future.关键词：Thin-shell;Flat-plate;Thermal buckling;Critical temperature
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发布时间：2022-09-22 - 摘要：The thermal deformation of the hydrostatic motorized spindle affects seriously machining precision,so it is necessary to analyze the effect factors of the thermal deformation of motorized spindle system. The process parameter and structural parameter are significant factors,such as the flow-rate of cooling water,the input pressure of bearing oil,the spindle speed and the bearing’s structural parameter. The results show that the maximum deformation of the motorized spindle system was in the place where the grinding wheel was installed. The variations of the flow-rate of cooling water and the input pressure of bearing oil affected the maximum deformation on the front surface of the spindle. When the flow-rate of cooling water or the input pressure of bearing oil was at a certain value,the thermal deformation was brought under effective control. If the flow-rate of cooling water or the input pressure of bearing oil increased more,the reduction of the thermal deformation was less. As the speed changed,the flow condition of the bearing oil was different. The maximum deformation of the spindle ’s front surface in the condition of turbulent flow was more than two times of that in laminar flow. The bearing’s length-to-diameter ratio and the length of bearing axial sealing edge were optimized,which minimized the maximum radical thermal deformation on the front surface of the spindle.关键词：Hydrostatic bearings;Parameter optimization;Motorized spindle;The thermal deformation
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发布时间：2022-09-22 - 摘要：An improved formula for fatigue crack growth rate in mode I,mode III and mixed mode I-III under different stress ratio R was proposed,which was based on J-integral range ΔJ. In the formula,the test data under different R could be normalized by correction factor M,which changed the test ΔJ under different R to ΔJeq0under R = 0,and the relationship of M and R was obtained empirically. The proposed formula was validated with available experimental fatigue crack growth data in mode I,mode III and mixed mode I-III under different stress ratio from literatures. It transpires that these test data can be well described with the present formula.关键词：Fatigue crack growth rate;J-integral;Mode Ⅰ,Ⅲ and Ⅰ-Ⅲ;Stress ratio;Improved formula
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发布时间：2022-09-22 - 摘要：Studying of probability distribution types of fatigue failure for GH4133 disc material,through the empirical distribution function and the average failure rate function methods to deal with the fatigue failure data. Based on the obtained data information,hypothesizing disk material fatigue failure probability distribution is the normal distribution, the lognormal distribution or the three parameter Weibull distribution. By means of parameter estimation for the three distributions,then using the Kolmogorov test of goodness fit method,to test the overall fitting effect of this distribution function. And to plot failure rate curves which distribution has been determined compare with the average failure rate curves. Comparing the data of each group which is under the same temperature with different strain ratio and the same stain ratio with different temperature then come to conclusion that the lognormal distribution is best fatigue failure distribution function for GH4133 disk material.关键词：Disk material;Fatigue failure;The empirical distribution;Goodness of fit test
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发布时间：2022-09-22 - 摘要：A unified constraint characterization parameter Aphas been defined based on the homogeneous material A508 in the previous study of authors. However,it is not clear that whether the unified correlation of in-plane and out-of-plane constraint with fracture resistance can be established by using the constraint parameter for the dissimilar metal welded joints（ DMWJs） or the bimetallic joint with highly heterogeneous mechanical property（ material constraint）. In this paper,the J-resistance curves of specimens under different in-plane and out-of-plane constraints for bimetallic joint were obtained by the FEM simulations based on GTN（ Gurson-Tvergaard-Needleman） damage model. And the equivalent plastic strain distributions ahead of crack tips for specimens with different constraint were calculated by the FEM model. After the fracture toughness JICand Apunder different constraint conditions were obtained,the unified correlation of in-plane constraint and out-of-plane constraint with fracture toughness of bimetallic joint was investigated. The results show that the Apis an appropriate unified constraint parameter which can characterize both geometry and material constraint,and can be used to established the unified correlation line between the fracture toughness and geometry constraint in bimetallic joint.关键词：In-plane/out-of-plane geometry constraint;Material constraint;Bimetallic joint;Fracture toughness;Structural integrity
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发布时间：2022-09-22 - 摘要：In this article,the new manifestation of crack propagation rate formula has been mainly studied when fatigue loads with diverse stress ratio and frequency acting on component with cracks. Linear and elastic crack propagation rate under fatigue loads with diverse stress ratio and frequency has been calculated quantificationally and accurately by modifying new crack propagation rate formula. Scope of application of modifying new crack propagation rate formula has been summarized where the effects of applied fatigue stresses,stress intensity factor transformation amplitudes at the fatigue crack tip are taken into considerations,accuracy and practicability of modifying new crack propagation rate formula having been tested.关键词：Stress ratio;Frequency;Propagation rate;Linear and elastic
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发布时间：2022-09-22 - 摘要：According to the understanding of the actual load effect on the rear axle,the invalid load interval of critical modulated signal can be decided to compile the multi-level program spectrum. The loading mode of bench test is simplified on the basis of recognization of the failure correlated load on the rear axle. Accordingly,the durability test of torsion beam rear axle is completed from the work above. The results show that the failure region of bench test is coincident with road test which can reach the accelerated assessment of durability,the acceleration factor is 5. 68.关键词：Accelerated test;Multi-level program spectrum;Failure-correlated-load;Durability
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发布时间：2022-09-22 - 摘要：Comparative analysis of two methods of analysis shaft fatigue strength including Chinese Machine Design Handbook method and American National Standard namely AGMA（ American Gear Manufacturers Association） standard ANSIAGMA 6001-D97 method. This essayanalysisthesecalculation process about these two methods and set examples to find out there major difference and their adaption to different situations.关键词：ANSI-AGMA 6001-D97;Fatigue strength of shaft;Comparison
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发布时间：2022-09-22 - 摘要：This paper predicted the crack growth life and residual strength of typical machined wing panel based on MCCI（ Modified Crack Closure Integral）. Compared with the result of the test evidence,the deviation of the prediction is acceptable by the engineering application. The results show that this method could be used in the research and development phase of the new aircraft project. Otherwise,the test results also show that the feature of machined stiffened panel cannot arrest the crack well.关键词：Wing panel;Crack growth;Residual strength;MCCI
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发布时间：2022-09-22 - 摘要：Double involute gear drive was a new type of gear drive. Based on the theory of friction,heat transfer and gear meshing,the friction heat flux and convection coefficient of double involute gear were calculated,considering the heat energy of friction contact between teeth as heat source. The temperature field finite element analysis was carried out by using ANSYS finite element software. The maximum temperature variation law of gear tooth was obtained through the simulation of the temperature field of the double involute gear under different step parameters.关键词：Double involute gear;Steady-state temperature field;Friction;Finite element method;Thermal analysis
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发布时间：2022-09-22 - 摘要：Brake pad is vibrating when it is friction contact with the brake disc surface in automotive disc brake mechanism.When the vibration rate is close to its natural frequency of the material. It is easily lead to unobvious craze and collapse in slice body structure. The natural frequency and the temperature field and the thermal field generated by the friction action of the brake disc are different from various pad material. Through the modal analysis of the disc brake pad in different material parameters,and use the ABAQUS to analyze the display dynamic thermal mechanical coupling in brake mechanism. Take the output results of the brake pad natural frequency and the brake disk node temperature,displacements,thermal stress compare with others. The data shows that the composite brake pad is better than the half metallic materials during brake process in avoid resonance and improve braking performance sides. The comprehensive analysis results and solutions,It has reference value in improving safety and brake efficiency aspects about the brake mechanism.关键词：Brake;Modal analysis;ABAQUS;Temperature field;Thermal-mechanical coupling
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发布时间：2022-09-22 - 摘要：Crashworthiness of square tube with reduced thickness at impacted end and dent under axial impact is analyzed by dynamic explicit FEM. Peak impact force can be reduced by reducing thickness of impacted end,but at same time irregular folding comes out. By stamping dent on tube,progressive buckling folding can be achieved. So crashworthiness of tube is improved by reducing thickness at impacted end and stamping dent.关键词：Square tube with reduced thickness at impacted end;Dent;Axial impact;FEM
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发布时间：2022-09-22 - 摘要：The three-dimensional model of the pressure screw pairs is established based on the finite element software ANSYS,the bearing characteristic of the pressure screw pairs structure is calculated at room temperature. By extracting the maximum value of each fastening screw tooth root of equivalent stress,verify the mill pressure screw pairs under equivalent stress distribution is in a U shape rules. The indirect coupling method was used for calculating the bearing characteristic of the pressure screw pairs are under thermal-structure coupling at 60℃ 、100℃ temperature. Comparison of equivalent stress of screw tooth and contact pressure of screw tooth surface under different temperature. The results show that the maximum contact pressure and equivalent stress occurred in the first fastening screw tooth,and when the temperature is at 100 ℃,the maximum equivalent stress of the nut is close to yield limit of the nut material.
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发布时间：2022-09-22 - 摘要：This paper is mainly focused on the dynamical response and the structural fatigue situation of a manual gear-box case,which is based on the stiffness coupling with the effect of the gears. First of all,the FEM model was established and the accurate model was acquired by comparing the simulation results with the experiment results. Then,we established the coupling analysis model of structure dynamics considering on parts of gears,shafts as well as the structural flexible case,using the Romax software. The working processes under different gears were simulated accurately by the model and the bearing loads of the gearbox were obtained. Then we loaded the frequency bearing load on the FEM model and obtained the stress response of the danger area. Finally,the vibration fatigue life on the danger area of the gear-box case was calculated and analyzed by the sample assessment method.关键词：Gear-box;Frequency domain incentive;Vibration fatigue;Life
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发布时间：2022-09-22 - 摘要：The cycloid magnetic gear transfers speed through the inner rotor rotation and revolution to get a higher transmission ratio and torque density. The permanent magnets were arranged by Halbach in order to improve the magnetic flux leakage and the utilization of permanent magnets,and a prototype was designed and manufactured according to the working principle. The magnetic field distribution and static torque characteristics of the cycloid permanent magnetic gear were researched by finite element simulation. Comparing with the general structure,it shows that the maximum torque density of even value can be increased by about 30% using 90° Halbach structure which has smaller fluctuations. Finally,the transmission torque of different angle were tested by experiments,the results are in accord with simulated results.关键词：Halbach array;Cycloid magnetic gear;Torque density;Static torque characteristics
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- 167
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发布时间：2022-09-22 - 摘要：In order to study the parameters of a folding wing‘s spreading performance which is used on the guided missile’s actuator,the unfolding performance was researched. First,a kinetic equation based on Lagrange’ s Equation was established,which provided a theoretic base for the simulation. Then,related dates such as deployable time,impact and stress of the rudder slice were obtained by rigid-flexible coupling dynamics imitating analysis of the spreading process through MSC. ADAMS.Finally,characters of the spreading performance and weak points affected by the impact were tested by experiments. The results show that the unfolding time is 175 ms,impulse strength is 42. 9N,which is less than the strength of the material,and meets the requirements of design. The performance can be described accurately by the simulation mode. Results of both simulations and experiments can provide theoretical basis for structural design and optimizing.
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发布时间：2022-09-22 - 摘要：Aiming at the motion request of spine and joints of these people who always sit in the office and according to the theory of ergonomics,a swing-style office lounge chair was designed. According to the testing standard of ANSI / BIFMA,static structure analysis and transient structure analysis was done under the environment of ANSYS Workbench. The stress and strain of the structure were calculated under the function load and proof load. The prototypes were made and tested,and the satisfied results were gotten. The research results indicate that the structure designed can meet the mechanical performance requirements of BIFMA,and the test results consistent with the analysis result. That verifies the accuracy and validity of the analysis,and it will benefit to shortening the development cycles and reducing development costs. The research results also offer important basis for the later structure optimization.关键词：Ergonomics;Swing chair;Static structure analysis;Transient structure analysis;Prototype test
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发布时间：2022-09-22
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