最新刊期
期 4 ， 2015
- 摘要：One of the important factors affecting the performances of semi-active suspension control is how to obtain the terrain information. A preliminary study is conducted to detect and memory the road conditions by which semi-active suspension switches control strategies or certain damping from one to another. The suspension adopts skyhook controllers designed for halfvehicle model in random road and uses small damping while passing an obstacle. The navigator advance informs the suspension controller as soon as it detects obstacles in front. Then the controller switches to small damping,thereby reducing the peak vibration and improve driving ride. Simulation proves the validity of this idea. Experiment using a real car is conducted after an onboard navigation system developed and the road conditions detection and memory search strategies are available. The experiment and simulation achieve similar results.关键词：Semi-active suspension;Onboard navigation system;Coordinated control;skyhook control;Control switch
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发布时间：2022-09-22 - 摘要：Based on the response sensitivity analysis on the identification of structural dynamic load,structural dynamic load was expressed as a series of parameters. To overcome the ill-posed problem during the process,the structural dynamic input load can be determined using the optimal parameters obtained by Genetic Algorithms. In the proposed method,the dynamics inverse problem was converted into the structural dynamics analysis and calculation,this can overcome the disadvantages of illconditioned matrix inverse,accumulated error and sensitive to initial conditions,etc. The numerical simulation result shows the proposed method is feasible.关键词：Force identification;Sensitivity analysis;Micro-genetic algorithms
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发布时间：2022-09-22 - 摘要：By means of Green’s function and modal expansion technique,the coupled vibration and sound equation of the finite cylindrical shells are investigated based on the flugge theory of the shells. The expression of the sound radiation and the radial quadratic velocity are solved. And then,the contributions of the low order vibration modes to the sound radiation and the radial quadratic velocity are also discussed in different fluids. The results show that more vibration modes contribute to the sound power of the finite cylindrical shells in air,however,the influence of the fluid-structure coupling on the radial squared velocity of the shells is very remarkable in water,the performance of the sound power radiated from the finite cylindrical shells is decreased with the increase of the circumferential vibration modes,and only first several vibration modes are required to accurately calculate the sound power.关键词：Finite cylindrical shells;Vibration modes;Sound radiation
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发布时间：2022-09-22 - 摘要：Longitudinal vibration of the elastic bars with concentrated masses widely exist in the engineering applications which needs to be studied deeply. In this paper,the harmonic dynamic disturbance was considered. At first,the equations to be determined were written out,the linear algebraic equations of the unknown coefficients were obtained utilizing the supposed harmonic solutions with unknown coefficients,boundary conditions of the problem and the dynamic conditions of the concentrated masses. The given example took three bars and two concentrated masses as the example,the vibration displacement amplitudes and the dynamic stress amplitudes of the bars along the axial direction with different disturbance frequencies were studied,The conclusions can provide the theoretical bases for the dynamic strength check and the strength design.关键词：Elastic bar with concentrated mass;Longitudinal harmonic vibration;Dynamic displacement amplitude;Dynamic stress amplitude
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发布时间：2022-09-22 - 摘要：The dynamic mechanical properties of oxygen free copper has been tested under the different strain rate（ 2 500s- 1 15 500 s- 1） at the room temperature by split Hopkinson pressure bar（ SHPB）,the true stress-true strain curves has been obtained. Power-Law constitutive model and Johnson-Cook constitutive model have been built to fit the experimental result from SHPB test of oxygen free copper. The results show that the plastic flow stress of oxygen free copper is not sensitive to the strain rate,however,the yield stress increases obviously and the strain strengthening effect decrease when the the strain rate is higher than 14 000 s- 1. In addition,the Power-Law constitutive model can predict the plastic flow stress of the oxygen free copper more accurately than the Johnson-Cook constitutive model at the high strain rate.关键词：Oxygen free copper;Split Hopkinson pressure bar;Constitutive model;Impact compression
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发布时间：2022-09-22 - 摘要：Using constant velocity universal drive shaft of Santana Automobile with different service lives,mechanical characteristics such as natural frequency and hardness were investigated. The results show that natural frequency of drive shaft decreases slightly with the increase of service life. The maximum of reduction for natural frequency is1. 2%. The high-rank natural frequency decreases more obviously than the low-rank,but no regulation was found. Surface hardness of different cross-sections changes slightly,which shows a trend from rise to decline. According to the changes of natural frequency and hardness,it predicts that drive shafts have over 60% service life.关键词：Constant velocity universal drive shaft;Natural frequency;Surface Hardness;Residual strength;Residual life
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发布时间：2022-09-22 - 摘要：The damage of the aeronautical PMMA is mainly due to the fatigue cracking leaded by the residual stress.Residual stress will produce the orientated segment or group in the aeronautical PMMA which produce the birefringence effect. In this paper,based on the birefringence effect,the digital phase-shift photoelasticity is used to test the residual stress for drilling the hole. For the test results some conclusions are summarized. When the feed speed is smaller,for the longer processing time the larger residual stress is frozen. When the rotational speed is greater,for the higher processing temperature the larger residual stress is frozen. Though controlling the chucking the constraints are the same in all directions. This can make the residual stress uniform and prevent the large stress concentration area. As machining the larger hole the smaller hole should be drilled firstly.This can ensure the smaller residual stress around the hole.关键词：Aeronautical PMMA;Residual stress;Digital phase-shift photoelasticity
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发布时间：2022-09-22 - 摘要：The paper adopts the testing technology of magnetic memory,and tests the Q235 B round hole specimen the leakage magic field around the round hole during the stretching process,to achieve the leakage magic field parametric distribution around the round hole in different loading stages. As the test specimens reached the specimen tensile strength,three kinds of pore size specimens take on the phenomenon that normal component value has greatly increased and the normal component of the gradient has suddenly changed in the local peak stress. This phenomenon proves that the magnetic memory method can forecast the stress concentration area. Meanwhile,according to the quantitative relationship between stress and magnetic in the peak position,and get the magnetoelastic effect irreversible component λHof Q235 B material under the experimental conditions,to provide the reference for the study of quantitative relation between local stress and magnetic memory characteristic value.关键词：Magnetic memory;Peak stress;Magnetoelastic effect irreversible component
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发布时间：2022-09-22 - 摘要：Based on ultrasonic vibration-assisted mode,high-frequency impacting tests with diamond indenter at different amplitudes on TiCrAlN coating of cutting tool are carried out. The microstructure and morphology are obtained by scanning electron microscopy（ SEM） and 3D profiler. The failure mechanism of coating under impacting is analyzed. The high frequency fatigue property of the coating is analyzed. The results show that: lateral crack could be seen under impacting test; the maximum tensile stress occurs close the edge of the contact zone of impact center; TiCrAlN coating is easy to emerge the fatigue damage under the high-frequency impact loading,and the adhesion strength of the coating and substrate interface affects the impact fatigue strength of cutting tool coating.关键词：Coating;Adhesion strength;High frequency impact;Fatigue failure
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发布时间：2022-09-22 - 摘要：Fault tree of automotive brake system and tire were set up according to their typical failure modes. We use the likelihood function and belief function of D-S theory respectively as the fault tree to analyze the upper and lower bounds of bottom event fault probability interval,we also apply the interval analysis theory to construct the AND operator,OR operator,and we conduct numerical computation on bottom event fault probability interval to solve the quantitative calculation problem of fault tree,thus to obtain probability interval of the top event fault,and reliability of automobile tire and brake system are analyzed and predicted. The calculation results show that this method is effective and feasible, which provide a reference design for improvement and the adjustment of automotive brake system and tire.关键词：Automotive brake system;Automotive tire;Fault tree;Interval analysis;D-S theory;Probability interval
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发布时间：2022-09-22 - 摘要：To improve the optimization efficiency of turbine stage optimization,an improved optimization strategy based on Bi-level integrated system synthesis（ BLISS2000） procedure to the multidisciplinary design optimization（ MDO） of turbine stage was proposed. The key idea in this approach is to keep the basic algorithm structure of BLISS2000,cancel the process to generate approximation models,and use variable complexity method（ VCM） which in the aerodynamic analysis. The approach was evaluated and validated by a turbine blade optimization problem. The results were similar as those in standard strategy,but the optimization efficiency increased by 2. 75 times.关键词：Bi-level Integrated system synthesis;Optimization strategy;Variable complexity method;Multidisciplinary design optimization;Turbine stage
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发布时间：2022-09-22 - 摘要：In the multidisciplinary optimization ISIGHT software environment,the comprehensive application of PRO / E parametric-modeling function and ABAQUS FEA function establish a framework of CAD / CAE integrated optimization design for tower door. Firstly,the parametric geometric model of door is built,Secondly,the FEA model is established and submitted. The interaction effects and the correlation factor between the geometric parameters and stress are analyzed by the DOE method of optimal LHD algorithm. Static strength optimization design of door is done by the ASA global optimization algorithm. The whole tower weight is as objection,the can strength the optimal design solutions of the door is gotten. The paper provides a scientific design method for strength optimization design of the tower door.关键词：FEA;Tower door;Opt LHD Algorithm;ASA Algorithm;Optimization design
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发布时间：2022-09-22 - 摘要：The limit bending-radius as the main straightening technical parameter,decides the structure of equipment and the quality of products for straightening thin-walled tubes with equal curvature,however,it is usually carried out based on the experiential data and chart by skilled labourers,whose art is based on long experience and experiments,the special mathematical model of the limit bending-radius is immediately necessary. Therefore,by means of the membrane shell theory and it’s relevant hypothesis the stress-strain state is proposed firstly,and based on plastic incremental theory,the limit bending-radius model for the prediction of diffuse plastic instability under pure bending is derived using Swift’s criterion. In order to certify whether it is correct,we have done the dynamic simulation by FEA,the results have shown that the model is approximate correct,finally the influencing factors of the limit bending-radius are analyzed qualitatively,this paper can also provide the basis for optimizing straightening technical parameters and completing the theory of thin-walled tube straightening.关键词：Thin-walled tube;Equal curvature straightening;Limit bending-radius;Tensile instability
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发布时间：2022-09-22 - 摘要：Aiming at the existing characters and deficiencies of the drilling experiment platform, a new kind of multifunctional drilling comprehensive experiment platform was designed. First of all,a new way to balance the drill rig load based on its design was put forward. Then by the internal and external balance methods,the results were calculated and compared,and the different effects on the experiment platform performance were obtained. Finally,according to the design characteristics of the drilling comprehensive experimental platform that could drill obliquely,the load mechanical property of the pit shaft was analyzed at different balance conditions,and the key technical parameters of the experiment platform design was got.The results show that the portal frame or pit shaft can support the drill pipe axial load in different balance ways. In essence,the load is transferred or transformed between the portal frame,pit shaft,track and foundation. Considering from the point of safety,using the scheme of the portal frame under load（ external balance mechanical system） is superior to the internal balance scheme of the pit shaft. The research method and conclusions have reference significance for optimal design,failure analysis and safety evaluation.关键词：Drill;Experiment platform;Design;Load;Balance;Mechanical property;Failure
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发布时间：2022-09-22 - 摘要：An oil pump is the core of machinery lubrication system components. With the base of the outside gear engine oil pump,the paper built a method in finite element and theory analysis aiming at the oil pump machine manufacture stuck phenomenon. The numerical simulation analysis to inner flow field of the pump was conducted by adopting CFX,with the Ansys Workbench,the machine solid thermosetting coupling structure analysis for the driven part of hot oil pump was studied,and combined with Matlab curve fitting interpolation,the stuck causes were found; On the basis of hydrodynamic pressure lubrication,the minimum oil film thickness,temperature rise and the bearing capacity were as the key analysis factors,ultimately the appropriate solutions were concluded aiming at stuck reasons. Finally with the corresponding physical experiment for verifying the improvement experiment,the rationality analysis of the results was verified,which provided the technical reference to model change of the future engine oil pump.关键词：Oil pump;ANSYS;Oil film thickness;MATLAB;Stuck
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发布时间：2022-09-22 - 摘要：The finite element transfer matrix method provides an efficient means to solve complex engineering problems,the state vector of traditional finite element transfer matrix method usually include linear and angular displacement,resulting in solving the transient dynamic problems has a strong dependence on numerical method. Based on this,this paper presents the finite element acceleration transfer matrix method for structural dynamic,the displacement in the state vector into acceleration,angular displacement into angular acceleration,to avoid the direct coupling of transfer matrix and numerical method,the finite element acceleration transfer matrix method for structural dynamic can conveniently solve the structural dynamics problems. At last,an example shows the validity of the proposed method.关键词：Finite element;Transfer matrix;Structural dynamics
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发布时间：2022-09-22 - 摘要：The energy absorbing property of corrugated tube subjected to axial crushing was researched through theoretical analysis. In view of the energy absorbing mechanism for axisymmetric deformation mode,a calculation formula for the mean crush load was put forward. It shows that the mean crush load is mainly influenced by the tube geometric parameters,material properties and loading rate. The theoretical analysis method was proved with the simulation results. Based on the theoretical analysis and numerical simulation effects of geometric parameters on the mean crush load were studied. Decreasing corrugation angle or increasing corrugation wavelength leads to accelerated increasing the mean crush load. Compared to the quasi-static crushing tests,the mean dynamic crush loads increase at about 80%. This work provides valuable theoretical guidance and design reference for the application of corrugated tube to structural crashworthiness field.关键词：Crashworthiness;Corrugated tube;Axial crush;Axisymmetric deformation;Theoretical analysis
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发布时间：2022-09-22 - 摘要：In this paper,the cylinder body-cylinder head-cylinder liner assembly coupled model is established based on the theory of elasticity and the method of contact. The cylinder liner deformation characteristics and the factors causing the deformation are studied under the preloaded cases. The results show that the four liners deformation is uneven and the first and the fourth cylinder liner are larger than the second and the third cylinder liner deformation. After optimizing the cylinder block,the cylinder liners radial distortion and deformation have decreased. With the bolt preload forces increasing,the cylinder liners deformation has increased. The closer cylinder head bolt counter bore depth is to the height of the cylinder convex shoulder,the greater the liners deformation is. When the cylinder convex shoulder angle is set to 20’,the liners deformation is relatively small.The length of action of cylinder head bolts has less influence on the radial deformation of cylinder liners.关键词：Bolt preload;Liner deformation;TCI diesel engine;Influencing factors
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发布时间：2022-09-22 - 摘要：A spatial 3T cable-driven parallel robot with four cables has been designed and manufactured. The kinematic models of the 3DOF cable-driven parallel robot have been established to discuss the deformation of cables in the large scale system. To check for the system’s zero position and analysis the error,the forward solution of kinematics has been carried out by Newton-Raphson iterative method. After analyzing the distribution of the dexterity,target tracks have been planned in the work space. Based on the inverse kinematics,the ideal curves of cables’ length have been reached. Based on catenary theory,the change of cables’ length have been calculated which is caused by the transformation,the result provide the theory basis for subsequent control.关键词：Spatial 3T;Cable-driven;Cable transformation;Dexterity;Trajectory planning
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发布时间：2022-09-22 - 摘要：Used the theory of a vector norm and matrix norm,derived the analytical relationship of the relative variation quantity between the moving platform speed or acceleration and active joint driving force or torque of mechanism,proposed the evaluation index to quantify the velocity and acceleration performance,approaches respectively the Jacobi matrix and inertia matrix singularity locus in the work space,two singular locus determines the mechanism workspace boundary,the public parts of them can be used as a working space with excellent dynamic performance. Analyzed the coupling effect of the active joint velocity and acceleration. Proposed the evaluation metrics of the coupling degree between the active joints. Combined with the example,analyzed the coupling between the mechanism velocity and acceleration performance and active joints.关键词：Parallel mechanism;Acceleration performance;Speed performance;Coupling
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发布时间：2022-09-22 - 摘要：Based on wrinkling model,a theoretical model for thermal barrier coating system was established. Using the temperature parameter method,the paper constructed the residual stress field of coating system,built the discrete format of finite element for lower coating shakedown analysis,and analyzed the effects of wrinkling degree and oxide layer thickness on coating system shakedown limit. Aiming at the geometric characteristics of wrinkling model,this paper translated it into a cylindrical model with three layers,provided analytic expressions for the shakedown limits,and then set up the simplified analytic model of thermal barrier coating. Compared with the numerical results,when C / L is less than 1 or C is far less than L,namely when wrinkle degree is not very drastic,the simplified model is close to the numerical results and it can be as an approximate calculation method for the shakedown limit of thermal barrier coating.关键词：Thermal barrier coating;Shakedown;Residual stress;Wrinkling model
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发布时间：2022-09-22 - 摘要：The magnetic memory testing and fuzzy evaluation theory is applied to the comprehensive safety evaluation of pressure vessel in service,and a comprehensive safety evaluation model of the pressure vessel in service is established. The defect parameters of pressure vessel in service are obtained using the magnetic memory testing method and the corresponding defect quantitative formula. The membership degrees of fatigue and fracture failure are solved based on the assessment method of fatigue and fracture of pressure vessel in service. Then according to the established factor set,evaluation set and weight set,the comprehensive safety assessment of pressure vessels in service is realized using the weighted average method. Finally,the comprehensive safety evaluation method based on the defect quantitative for the pressure vessel in service is got and an example is provided.关键词：Pressure vessel;Safety evaluation;Fuzzy mathematics;Defect size
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发布时间：2022-09-22 - 摘要：Based on the fatigue life damage theory,the load contribution to the fatigue life was analyzed,then dispensed part frequency of small load to other load levels. The corresponding stress distribution was obtained using the software of ANSYS;the fatigue damage of worm gear was calculated by correlating results of ANSYS and the time history using the software of n Code,and compared with the experimental results. This paper presented specific calculation method,and analyzed reliability and feasibility of accelerated fatigue of worm and gear.关键词：Fatigue damage;Accelerated fatigue;Load spectrum;Structural stress;Worm and gear
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发布时间：2022-09-22 - 摘要：Casting crane is widely used as hoisting and conveying equipment in the metallurgical industry. The bad and failure working environment caused remarkable accident harm,so mechanical properties and fatigue analysis accurately on this equipment seem very important. Establishing bridge’s 3D model and dynamic model reasonably for the 200 /63 t crane which made up by four beams,runways and double trolley. Base on the actual load characteristics and dynamic parameter analysis,and finishing the transient dynamic analysis in the ANSYS software for the bridge crane through structure simplify reasonably and boundary conditions. On the basis of obtaining accurate stress dynamic response with the dangerous girder structure,and then combine with the theory of linear elastic fracture mechanics theory,addressing the fatigue crack propagation life of beans under impact load. This study provide the theory basis for the structure optimization and reliability design of crane.关键词：Casting crane;Transient dynamic;Fatigue crack propagation life;Fracture mechanics;Impact load
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发布时间：2022-09-22 - 摘要：Based on the work status of the aero-engine turbine blade,the contact fatigue tests of modeling specimens of tenon / groove were carried out. A fatigue crack growth life model of the modeling specimens was established. The crystallographic finite element program was implemented to study the stress field of the tenon / groove. Crack growth lives obtained from the finite element analysis had a good agreement with the results of experiment. It was demonstrated that the life model could be used in engineering to predict the remaining life of turbine disk.关键词：Nickel-based turbine blade;Tenon / groove;The contact fatigue;Crack growth life
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发布时间：2022-09-22 - 摘要：With Nominal Stress Method of pumping unit horse head fatigue life prediction results deviate from the actual,introduction of the Stress Field Intensity Approach,the prediction step of the two methods is given. Based on the cyclic and alternating load analysis of horse head,do static simulation in the ANSYS simulation environment,calculate stress under the ultimate load; do Quasi-static simulation,calculate stress and partial damage regional stress field which changes over time.According to the steps,deal with the simulation results and get the fatigue life prediction of the two kinds of methods. Making count a figure of horse head life and fit the fatigue life distribution to verify accuracy of the two methods,analysis the reason of different result error. The result shows that the Stress Field Intensity Approach forecasting accuracy is higher,predicted result fits the actual.关键词：The Pumping unit;Horse head;Fatigue life prediction;Stress field intensity approach
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发布时间：2022-09-22 - 摘要：This paper deals with a new micromechanics model of particulate- reinforced composites（ PRCs） which can describe the evolution of debonding damage,matrix plasticity and particle size effect on the deformation. Based on the preceding researches,a ductile interphase was considered in the frame of incremental damage theory to describe the dependence of elasticplastic-damage behavior on particle size. Progressive damage was controlled by a critical energy criterion for particle-matrix interfacial separation. The equivalent stresses of the matrix and interphase were determined by field fluctuation method. The influences of progressive debonding damage,particle size and interphase properties on the overall stress-strain response of PRC were analyzed. Due to the existence of a ductile interphase, stress transfer and plastic initiation in PRC become very complicated,and a unit-cell（ UC） based FEM was used to understand their evolution and demonstrate the role of the interphase.Finally,particle size effect on the mechanical behaviors of composites was interpreted.关键词：Particulate-reinforced composite（PRC）;Ductile interphase;Finite element method（FEM）;Debonding damage
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发布时间：2022-09-22 - 摘要：For effectively calculating the static and dynamic mechanical properties of complex air gear box,use several finite element entity unit type that is commonly used in ANSYS software,then carry out The finite element meshing,static analysis and dynamic analysis on gearbox. The example compare the influence of different type of element unit of the consuming time and the accuracy of the results,give some suggests for the selection of element unit.关键词：Aviation gearbox;ANSYS;Element type;Grid density;Finite element analysis
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发布时间：2022-09-22 - 摘要：For the problem of excessive stresses in the runner after hydraulic turbine reformation,two solutions are put forward in this paper,which are the extension of the outlet edge of the blade near the crown and applying reinforcing triangular piece. In order to identify the loads acting on the runner,the water flow of whole passage has been investigated by using CFD method. The water pressure was loaded on the finite element model of runner,and rigidity ＆ strength analysis was conducted.The maximum equivalent stress and the maximum deformation of runner in two solutions were obtained. The results show that: the maximum stress of the original runner appears in rated condition,because the pressure difference between the pressure side and suction side at the center of blade and outlet of near the crown is very big,thus the distribution of load is uneven. Under the rated condition,the maximum stress of blade decreases by 14. 5% in the same degree in both the two solutions. The maximum total deformation of blade in solution A is greater than which in solution B. The maximum stress is located in the the intersection of triangular piece and blade outlet,which is a little far from the blade root,so the force condition of blade root is improved effectively. At the same time,the flow field analysis results show that energy characteristics and the cavitation performance in the two solutions under various operating conditions is less affected.关键词：Francis Turbine;Outlet Edge of Blade;Triangle Piece;Rigidity ＆ Strength Analysis;FEM
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发布时间：2022-09-22 - 摘要：A two-dimensional finite element model of orthogonal cutting Inconel 718 has been built by Third Wave Advant Edge to obtain the distribution of temperature and stress under different parameters of the cutting edge. The cutting force predicted by the finite element method（ FEM） showed good agreement with the experimental results. The optimize processes of the cutting edge parameters has been proposed and the effect of cutting edge parameters on cutting stress and cutting temperature have been analyzed. Then,the optimal parameters of cutting edge on the processing of nickel-based alloy are selected. It finds that,with given relief angle of 7°,the optimal rake angle is 6°and the optimal cutting edge radius is 60μm. Basically,with the increase of the rake angle,cutting temperature gradually increases and the tool stress decreases firstly and then increases,and the temperature of chips decreases and the high stress area expands to the flank face of tools. With the increase of the cutting edge radius,cutting temperature increases and tool stress decreases firstly and then increases,and stress concentration of cutting edge is weakened.关键词：Nickel base alloys;FEM;Cutting temperature;Tool stress;Optimize cutting edge geometrical parameters
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发布时间：2022-09-22 - 摘要：In order to solve the problems of M-pressure pump crankshaft fracture,full analysis of the M-pump caranshaft fracture was congducted. On this basis,stress analysis was carried out on the crankshaft by ANSYS. Through simulation analysis found that severe stress concentration sites coincide with the cleavage site,and conducted a simulation influence on the fracture of the crankshaft chamfer,and re-determine the size of the chamfer. To further verify the situation fracture,the fatigue strenth of frature section were checking calculation by analtical method. The results show,fatigue strength safety factor below allowable safety factor under the original conditions of the crankshaft 4mm chamfer,and fatigue strength safety factor to meet the design requirements in the case of 8mm chamfer. Improved design was performed according to the results of the simulation and calculation of the crankshaft,and applications significant effect,solved the problem of crankshaft fracture.关键词：Crankshaft fracture;Chamfer;ANSYS;Fatigue strength
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发布时间：2022-09-22 - 摘要：Composite drillbit spherical sliding bearing is a new structure of bit bearing. There is no related literature to make thorough study of its mechanical behavior. Therefore,the ANSYS finite element analysis was adopted to establish the spherical composite bearing three-dimensional model; Used the contact finite element calculation to comparison and analysis the surface pressure distribution size and regularity of spherical and cylindrical; Lastly,used the spherical radius as design variables and the peak contact pressure as objective function establish composite bit sliding bearing optimization design model. The optimization results show that: the peak contact pressure decreased 50. 6%. The peak stress of von Mises decreased 17. 7%. The contact pressure distribution is more reasonable. The new structure can effectively improve the sliding bearing service life and working reliability.关键词：Composite drilling bit;Sliding bearing;Spherical shape;Optimization design
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发布时间：2022-09-22 - 摘要：Aiming at the problem of the FPCB（ flexible printed circuit board） stiffener adhesive machine performance optimization,applying the finite element method,a FEA model of the FPCB stiffener adhesive machine has been set up. The stiffness and modal analysis of the current structure have been done. According to simulation results,there was a large deformation at the marble platform. The first and second inherence frequencies of the structure were rather low. Therefore,do the optimization and improvement design to strengthen this structure. After improvement design,the stiffness and each natural frequency of this machine have improved a lot. The experiment testing shows that,the stability and the position accuracy of this machine have improved a lot after improvement design.关键词：Finite element method;Simulation and analysis;PCB;Stiffener adhesive machine;Improvement design;Verification
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发布时间：2022-09-22 - 摘要：In this article,elastic-plastic curved crack tip opening displacement in hardened material under quasi-static loads has been mainly studied,and curved crack tip opening displacement has been calculated as a practical application of a second order perturbation method and theorem of surname KA,where the effects of quasi-static applied stresses and quasi-static normal and shear stresses on the boundaries of plasticity area are synthetically taken into considerations. Diagrams have been constructed to analyse the transformation relationships between curved crack tip opening displacement size and hardening exponents. Curved crack tip opening displacement will decrease when hardening exponents increase in hardened material. The decrease extent of curved crack tip opening displacement will be more and more severe when hardening exponents increase evenly. Curved crack tip opening displacement will decrease when external loads decrease with the same hardening exponents. A brand new domain of theoretical model where CTOD was calculated has been reclaimed in hardened material.关键词：Quasi-static loads;Hardened material;Curved crack;A second order perturbation solution;CTOD
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发布时间：2022-09-22 - 摘要：With the method of CFD,pressure loss of the muffle in different flow rates were calculated by using numerical calculation. Then based on the FLUENT software,the pressure loss of the muffle was simulated,and the influence of structure on the pressure loss was analyzed. On the basis,the structure of the muffler was optimized. The results show that the reasonable arrangement of the intubation and perforated pipe can reduce the pressure loss effectively,which provided a theoretical basis for the optimization design of the muffler.关键词：CFD;Numerical calculation;Pressure loss;Optimization
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发布时间：2022-09-22 - 摘要：The moving system is the most critical part of numerical control（ NC for short） forming machine to achieve its fundamental function,but also the most importent part that affect the processing accuracy. The moving system of forming machine were lightweight designed firstly. Based on lightweight design principles,aluminum material was adopted on its key components of Y and Z axis,and the sandwich structure which has advantages of lightweight core and large inertia moment. Then structural static analysis and mode analysis of moving system were done by using the method of FEM numerical simulation,and the engineering verification was carried out. Results of the study show that the strength and stiffness of the moving system can satisfy the use requirement and allowable conditions of the forming machine.关键词：NC forming machine;Moving system;Lightweight design;Static analysis;Mode analysis
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发布时间：2022-09-22 - 摘要：Using the ANSYS finite element analysis software to analyze the modal of the case and its modules by the substructure method,the natural frequency and mode shape of the equipment are obtained. Synthesizing the results of the modal analysis,the comprehensive structure improvements recommendations are proposed. And the substructure method has important reference value for the large-scale electronic equipments.关键词：Finite element;Sub-structure;Modal analysis;Electronic equipment
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发布时间：2022-09-22
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