Author Center
Editor Work
Peer Review
Editorial Entry
Email Alert
RSS2012 Vol. 31, No. 9
Display Method:
2012, 31(9): 1377-1383.
PDF 1800KB
Abstract:
The temperature and stress distribution in brake pads is a key factor for the high-speed multiple units safe operation. According to the heat transfer theory and using the finite element simulation technology, a heat con-duction model of brake pad was established in this paper. The impact due to the elastic modulus, poisson ratio, thermal conduction and specific heat was considered and the calculation method of thermal load and heat transfer coefficient was also presented. A 3 D thermal-stress coupling simulation model for the braking of brake pad was built by software ANSYS. Then the dynamic temperature and stress distribution in the braking of brake pad were ob-tained and verified by experiemnts. The simulation result shows that the brake pad would reach the max temperature 535 ℃at 62 s and the max stress 333 MPa at 75 s. Owing to the temperature simulation results in accordance with the expermental results basically, it could demonstrate that the simulation method was effective and this type of brake pads studied in the paper met the practice requirements.
The temperature and stress distribution in brake pads is a key factor for the high-speed multiple units safe operation. According to the heat transfer theory and using the finite element simulation technology, a heat con-duction model of brake pad was established in this paper. The impact due to the elastic modulus, poisson ratio, thermal conduction and specific heat was considered and the calculation method of thermal load and heat transfer coefficient was also presented. A 3 D thermal-stress coupling simulation model for the braking of brake pad was built by software ANSYS. Then the dynamic temperature and stress distribution in the braking of brake pad were ob-tained and verified by experiemnts. The simulation result shows that the brake pad would reach the max temperature 535 ℃at 62 s and the max stress 333 MPa at 75 s. Owing to the temperature simulation results in accordance with the expermental results basically, it could demonstrate that the simulation method was effective and this type of brake pads studied in the paper met the practice requirements.
2012, 31(9): 1384-1389.
Abstract:
In order to analyze dynamic strength reliability of mechanism, taking the component section sizes, mate-rial strength and density and gravity acceleration as the random variables, and based on the movement analysis and the dynamic analysis taking the Assur-Group as unit, the analysis method of dynamic strength reliability for the crank-slide mechanism was established. The example was analyzed by using the Monte Carlo (MC) method and the MFOSM (Mean First Order Second Moment) method. The reliability curves about the dynamic strength were at-tained. The result indicates that the velocity of the pesent method is high, and the precision is high too.
In order to analyze dynamic strength reliability of mechanism, taking the component section sizes, mate-rial strength and density and gravity acceleration as the random variables, and based on the movement analysis and the dynamic analysis taking the Assur-Group as unit, the analysis method of dynamic strength reliability for the crank-slide mechanism was established. The example was analyzed by using the Monte Carlo (MC) method and the MFOSM (Mean First Order Second Moment) method. The reliability curves about the dynamic strength were at-tained. The result indicates that the velocity of the pesent method is high, and the precision is high too.
2012, 31(9): 1390-1394.
Abstract:
In this study, the objective function and constraints of the hybrid ceramic bearing mined; the optimal design of the bearing was completed using the efficiency coefficient method design was deter-combining with the computer-aided program. Through the comparative analysis of the heat productivity of hybrid ceramic rolling bearing and sliding bearings, the former's was significantly lower than the latter's, thus the hybrid ceramic rolling beating proved its advantages. The ciency increased 5% ~ 8% bench test of engine turboeharger hybrid ceramic bearing showed that the overall effi-and its limit speed increased up to 120 000 r/min.
In this study, the objective function and constraints of the hybrid ceramic bearing mined; the optimal design of the bearing was completed using the efficiency coefficient method design was deter-combining with the computer-aided program. Through the comparative analysis of the heat productivity of hybrid ceramic rolling bearing and sliding bearings, the former's was significantly lower than the latter's, thus the hybrid ceramic rolling beating proved its advantages. The ciency increased 5% ~ 8% bench test of engine turboeharger hybrid ceramic bearing showed that the overall effi-and its limit speed increased up to 120 000 r/min.
2012, 31(9): 1395-1400.
Abstract:
Current beveloid gears' tooth thickness variation is achieved by changing modification coefficient, so the intersecting lines between the tooth profile and any arbitrary cross section perpendicular to the gear's axis are differ-ent segments of the same involute, which leads to the gear producing a certain conical degree along the gear's axial direction. A new base circle moved heveloid gear (BCMBG) is presented in this paper, which is realized through moving the base circle. BCMBG has the same tooth depth in the tooth direction and the intersecting lines between the tooth profile and any arbitrary cross section perpendicular to the gear's axis are the same segment of an involute, eliminating the possible interference in the clearance adjusting process of conventional beveloid gears. Firstly, tooth surface equations of the new beveloid gear are derived, in which parameter θ determines tooth thickness's variation quantity. In addition, the discrete data is obtained by using Matlab and then imported into Pro/E to establish the beveloid gear's accurate geometric model, according to which the prototype of the proposed beveloid gear is made to verify the tooth surface equations. Finally, the contact model of the heveloid gear's tooth surface at the transmission pair is constructed, and the transient contact points and contact lines are calculated with Matlab.
Current beveloid gears' tooth thickness variation is achieved by changing modification coefficient, so the intersecting lines between the tooth profile and any arbitrary cross section perpendicular to the gear's axis are differ-ent segments of the same involute, which leads to the gear producing a certain conical degree along the gear's axial direction. A new base circle moved heveloid gear (BCMBG) is presented in this paper, which is realized through moving the base circle. BCMBG has the same tooth depth in the tooth direction and the intersecting lines between the tooth profile and any arbitrary cross section perpendicular to the gear's axis are the same segment of an involute, eliminating the possible interference in the clearance adjusting process of conventional beveloid gears. Firstly, tooth surface equations of the new beveloid gear are derived, in which parameter θ determines tooth thickness's variation quantity. In addition, the discrete data is obtained by using Matlab and then imported into Pro/E to establish the beveloid gear's accurate geometric model, according to which the prototype of the proposed beveloid gear is made to verify the tooth surface equations. Finally, the contact model of the heveloid gear's tooth surface at the transmission pair is constructed, and the transient contact points and contact lines are calculated with Matlab.
2012, 31(9): 1401-1405.
Abstract:
Process parameters of self-piercing riveting have significant effects on the performance of the rivet joints. In this paper, the influence of rivet height and edge distance on joint strength is analyzed by experimental method. In different rivet edge distances, two steel sheets with 1 mm thickness were riveted together with semi-tubular rivets which have a diameter of 5.3 mm and different heights. Tensile tests of rivet joints were conducted, and the load-displacement curves were obtained. The results show that self-piercing riveting quality is good when rivet is 3 mm higher than riveting sheet. When the rivet edge distance is less than 10 mm, it will have an impact on the rivet joint strength, and the shorter the rivet edge distance, the lower the joint strength.
Process parameters of self-piercing riveting have significant effects on the performance of the rivet joints. In this paper, the influence of rivet height and edge distance on joint strength is analyzed by experimental method. In different rivet edge distances, two steel sheets with 1 mm thickness were riveted together with semi-tubular rivets which have a diameter of 5.3 mm and different heights. Tensile tests of rivet joints were conducted, and the load-displacement curves were obtained. The results show that self-piercing riveting quality is good when rivet is 3 mm higher than riveting sheet. When the rivet edge distance is less than 10 mm, it will have an impact on the rivet joint strength, and the shorter the rivet edge distance, the lower the joint strength.
2012, 31(9): 1406-1410.
Abstract:
Using the fuzzy control toolbox embedded in Matlab, the fuzzy controller for phase difference was de-signed for active eccentric block and driven eccentric block in the hydraulic vibrohammer ( type SFA1600, medium-frequency hydraulic vibrohammer). The fuzzy controller was optimized with parameter self-adjusting method and the simulation model was developed. The results showed that parameter self-adjusting fuzzy controller regulated phase difference very well to avoid the problem of non-synchronous vibration. The error between the difference and the given phase difference was small. Compared regulated phase with the basic fuzzy controller, parameter self-adjus-ting controller possessed the advantages of fast response, good stability and small steady-state error.
Using the fuzzy control toolbox embedded in Matlab, the fuzzy controller for phase difference was de-signed for active eccentric block and driven eccentric block in the hydraulic vibrohammer ( type SFA1600, medium-frequency hydraulic vibrohammer). The fuzzy controller was optimized with parameter self-adjusting method and the simulation model was developed. The results showed that parameter self-adjusting fuzzy controller regulated phase difference very well to avoid the problem of non-synchronous vibration. The error between the difference and the given phase difference was small. Compared regulated phase with the basic fuzzy controller, parameter self-adjus-ting controller possessed the advantages of fast response, good stability and small steady-state error.
2012, 31(9): 1411-1419.
Abstract:
Environment vibration directly leads to dynamic performance degradation and becomes one of key impact factors on the precision equipment performance. Active vibration isolator is used to damp the environment vibration both from base disturbance and direct disturbance in order to maintain the stability of the payload of precision equipment. Active vibration isolators are classified into hard mounts and soft mounts according to its natural fre-quency. Hard mounts are commonly used to damp direct disturbance and structure mode of the payload with their high stiffness while soft mounts are used to isolate the base disturbance. The technological prospects about struc-tures of both soft mounts and hard mounts are given and some challenges and unsolved key technologies for the structure of active vibration isolator are proposed.
Environment vibration directly leads to dynamic performance degradation and becomes one of key impact factors on the precision equipment performance. Active vibration isolator is used to damp the environment vibration both from base disturbance and direct disturbance in order to maintain the stability of the payload of precision equipment. Active vibration isolators are classified into hard mounts and soft mounts according to its natural fre-quency. Hard mounts are commonly used to damp direct disturbance and structure mode of the payload with their high stiffness while soft mounts are used to isolate the base disturbance. The technological prospects about struc-tures of both soft mounts and hard mounts are given and some challenges and unsolved key technologies for the structure of active vibration isolator are proposed.
2012, 31(9): 1420-1423.
Abstract:
Special shaped-screw is widely used in some industries, and the machining process is different trom most normal parts. A new method of numerical control(NC) programming to machine screw is proposed, in which the screw face is cut by cutter moving through screw curve track. The method can be used in machining screw with line-shaped groove and curve-shaped groove. Screw process and machining tools are introduced. Computing coordi-nates of cutter location points, NC programming, cutting method, Computing tool step, and Computing stepover length are researched. The application results verify the validity of the present techniques.
Special shaped-screw is widely used in some industries, and the machining process is different trom most normal parts. A new method of numerical control(NC) programming to machine screw is proposed, in which the screw face is cut by cutter moving through screw curve track. The method can be used in machining screw with line-shaped groove and curve-shaped groove. Screw process and machining tools are introduced. Computing coordi-nates of cutter location points, NC programming, cutting method, Computing tool step, and Computing stepover length are researched. The application results verify the validity of the present techniques.
2012, 31(9): 1424-1428.
Abstract:
Counter-rotating turbine can improve the performance of aviation turbine engines, and the design without nozzle guide vane is one of the the development trends. In counter-rotating turbine, low pressure rotor blades are operated by wake of high pressure turbine. In this paper, numerical analysis of a low-pressure turbine blade is pres-ented by using fluid-structure interaction method of ANSYS/CFX software. In this approach, the stress distribution and vibration characteristics of the rotor blade under high pressure rotor blade wake are computed. The results show that blade temperature evidently affects the average value, amplitude and period of vibration stress and ment, the density of blade material impacts vibration period. The selction of axial distance between high turbine should consider some factors such as turbine efficiency. displace and low.
Counter-rotating turbine can improve the performance of aviation turbine engines, and the design without nozzle guide vane is one of the the development trends. In counter-rotating turbine, low pressure rotor blades are operated by wake of high pressure turbine. In this paper, numerical analysis of a low-pressure turbine blade is pres-ented by using fluid-structure interaction method of ANSYS/CFX software. In this approach, the stress distribution and vibration characteristics of the rotor blade under high pressure rotor blade wake are computed. The results show that blade temperature evidently affects the average value, amplitude and period of vibration stress and ment, the density of blade material impacts vibration period. The selction of axial distance between high turbine should consider some factors such as turbine efficiency. displace and low.
2012, 31(9): 1429-1433.
Abstract:
To meet the needs of the multi-mission, multi-model and batch production of satellite products, we pro-pose a satellite product configuration method that uses the product category database. The core of the method con-sists of: ( 1 ) we use the product development architecture to establish the product category database on two levels : satellite platform and device; the database contains the specification, function and performance of a product; (2) through data mining, we extract the satisfactory product category data from the product category database; (3) we establish the product category in the product data management system to manage the mined data category by catego-ry; (4) we introduce the product configuration management technology to build a design navigator that is oriented to both satellite platform and device by using the product category database and the configurable product structure tree. With our satellite product configuration method, satellite product developers can rapidly configure and develop satellite products as required by different missions of a satellite.
To meet the needs of the multi-mission, multi-model and batch production of satellite products, we pro-pose a satellite product configuration method that uses the product category database. The core of the method con-sists of: ( 1 ) we use the product development architecture to establish the product category database on two levels : satellite platform and device; the database contains the specification, function and performance of a product; (2) through data mining, we extract the satisfactory product category data from the product category database; (3) we establish the product category in the product data management system to manage the mined data category by catego-ry; (4) we introduce the product configuration management technology to build a design navigator that is oriented to both satellite platform and device by using the product category database and the configurable product structure tree. With our satellite product configuration method, satellite product developers can rapidly configure and develop satellite products as required by different missions of a satellite.
2012, 31(9): 1434-1438.
Abstract:
The dynamic mathematical model of cartridge inserted hydraulic poppet transient simulations are carried out by CFD software for both practical poppet valve valve is set up. Its steady and vibrating strongly and its modi-fled structures. The reasons causing poppet valve vibration are researched. The modeling analysis result shows that the steady-state hydraulic flow force which makes the valve opening is one of the primary reasons that intensify valve vibration. The steady CFD simulation results show: the steady-state flow force of original poppet valve increases firstly and reduces later with the opening of valve port, but the force's direction is always upward, which makes the spool of poppet valve has the tendency to open, this could be the reason why the valve vibrates strongly. The transi-ent calculation results indicate that the modified valve structures can reduce vibration indeed, but these structures will cause more negative pressure, which may leads to the cavitations and cavitations' noise.
The dynamic mathematical model of cartridge inserted hydraulic poppet transient simulations are carried out by CFD software for both practical poppet valve valve is set up. Its steady and vibrating strongly and its modi-fled structures. The reasons causing poppet valve vibration are researched. The modeling analysis result shows that the steady-state hydraulic flow force which makes the valve opening is one of the primary reasons that intensify valve vibration. The steady CFD simulation results show: the steady-state flow force of original poppet valve increases firstly and reduces later with the opening of valve port, but the force's direction is always upward, which makes the spool of poppet valve has the tendency to open, this could be the reason why the valve vibrates strongly. The transi-ent calculation results indicate that the modified valve structures can reduce vibration indeed, but these structures will cause more negative pressure, which may leads to the cavitations and cavitations' noise.
2012, 31(9): 1439-1444.
Abstract:
In the field of green design and manufacturing, one of the important contents is how to select the best green material among the feasible solutions. Life cycle assessment (LCA) was above all implemented. According to the idea of concurrent design, not only the properties of candidate materials but also the recycling methods to be taken should simultaneously be considered. This paper derived similarity close degree (SCD) with improved grey incidence analysis, while with the technique for order preference by similarity to ideal solution (TOPSIS) distance close degree (DCD) could be derived, and the integration close degree (ICD) could further be derived with the nonlinear pro-gramming model based ori the concept of the minimum deviation between the ICD and SCD and between it and DCD. And combination series were ranked according to ICD. An illustrative example was given to demonstrate the whole process of decision making, and to verify the advantages in comparison with the other methods of decision making. Finally, this work presents two problems to be solved in decision making on green materials based on LCA.
In the field of green design and manufacturing, one of the important contents is how to select the best green material among the feasible solutions. Life cycle assessment (LCA) was above all implemented. According to the idea of concurrent design, not only the properties of candidate materials but also the recycling methods to be taken should simultaneously be considered. This paper derived similarity close degree (SCD) with improved grey incidence analysis, while with the technique for order preference by similarity to ideal solution (TOPSIS) distance close degree (DCD) could be derived, and the integration close degree (ICD) could further be derived with the nonlinear pro-gramming model based ori the concept of the minimum deviation between the ICD and SCD and between it and DCD. And combination series were ranked according to ICD. An illustrative example was given to demonstrate the whole process of decision making, and to verify the advantages in comparison with the other methods of decision making. Finally, this work presents two problems to be solved in decision making on green materials based on LCA.
2012, 31(9): 1445-1448.
Abstract:
After a new computing method of threshold and a new choosing method ot characteristic value oi singular value were developed, and an improved de-noising method was presented by combining wavelet packet and singular value de-noising method, aiming at the shortcomings of conventional de-noising methods that based on the frequen-cy spectrum difference between noise and signal. In the new method, vibration signals are first decomposed by the wavelet packet, and then the new threshold de-noising on the wavelet packet coefficient is used. Finally, the recon-struction signal is de-noised by the singular value decomposition. Experimental results show that the new method has better de-noising effect than other conventional methods and efficiently reduces the noise of the vibration signal of gear pump, and it provides an effective method for pretreating vibration signal of gear pump.
After a new computing method of threshold and a new choosing method ot characteristic value oi singular value were developed, and an improved de-noising method was presented by combining wavelet packet and singular value de-noising method, aiming at the shortcomings of conventional de-noising methods that based on the frequen-cy spectrum difference between noise and signal. In the new method, vibration signals are first decomposed by the wavelet packet, and then the new threshold de-noising on the wavelet packet coefficient is used. Finally, the recon-struction signal is de-noised by the singular value decomposition. Experimental results show that the new method has better de-noising effect than other conventional methods and efficiently reduces the noise of the vibration signal of gear pump, and it provides an effective method for pretreating vibration signal of gear pump.
2012, 31(9): 1449-1453.
Abstract:
For the signal processing based on singular value decomposition, the faint fault feature is hard to be ex-tracted from the gear vibration signals. A selection method of effective singular values is proposed here to solve problem. By using every separate singular value, the one-dimensional signals are reconstructed. The frequency spectrums of the reconstructed signals are gained through Fast Fourier Transformation (FFT). Chose the singular values which correspond with the feature frequency in the gear signal; and use them to reconstruct the signal as the ultimately result. The procession results show that this method can extract the faint fault feature from the gear crack fault signal and it can be widely used in the fault feature extraction of the rotating machinery.
For the signal processing based on singular value decomposition, the faint fault feature is hard to be ex-tracted from the gear vibration signals. A selection method of effective singular values is proposed here to solve problem. By using every separate singular value, the one-dimensional signals are reconstructed. The frequency spectrums of the reconstructed signals are gained through Fast Fourier Transformation (FFT). Chose the singular values which correspond with the feature frequency in the gear signal; and use them to reconstruct the signal as the ultimately result. The procession results show that this method can extract the faint fault feature from the gear crack fault signal and it can be widely used in the fault feature extraction of the rotating machinery.
2012, 31(9): 1454-1457.
Abstract:
The Redundant Servo Motor (RSM) Approach is applied to the dynamic balance of elastic linkage mechanism. The principle of RSM is that the real-time variable speed of motor may be redundant to kinematic mo-tion generation of a mechanism and utilized for the purpose of dynamic balance of mechanism. The RSM procedure ~'s applied to a four-bar elastic linkage (as an example). Its elastic dynamic optimization model is established and the balance principle of the present approach is illustrated. Five kinds of motion have been carried on the optimiza-lion model. The simulation result has shown the effectivity on the balance of shaking force and shaking moment and also a great promise by comparing it with the approach which adds an extra servomotor in the mechanism.
The Redundant Servo Motor (RSM) Approach is applied to the dynamic balance of elastic linkage mechanism. The principle of RSM is that the real-time variable speed of motor may be redundant to kinematic mo-tion generation of a mechanism and utilized for the purpose of dynamic balance of mechanism. The RSM procedure ~'s applied to a four-bar elastic linkage (as an example). Its elastic dynamic optimization model is established and the balance principle of the present approach is illustrated. Five kinds of motion have been carried on the optimiza-lion model. The simulation result has shown the effectivity on the balance of shaking force and shaking moment and also a great promise by comparing it with the approach which adds an extra servomotor in the mechanism.
2012, 31(9): 1458-1462.
Abstract:
In order to control excavator automatically, an excavator was retrofitted with electro-hydraulic control system. Nonlinear models for electro-hydraulic proportional valve and valve-controlled asymmetric cylinder were built respectively, and then the nonlinear state space model for the whole system was achieved. Simulation experi-ments showed that the steady error, delay and flat-headed effect were aroused by the dead-band nonlinearity, and also testified the dissymmetry character of valve-controlled asymmetric cylinder. According to the nonlinear charac-ter, a piecewise PID with dead-band compensation was adopt, and the comparison experiment showed that the pro-posed controller could overcome the affects of dead-band and asymmetric nonlinearities.
In order to control excavator automatically, an excavator was retrofitted with electro-hydraulic control system. Nonlinear models for electro-hydraulic proportional valve and valve-controlled asymmetric cylinder were built respectively, and then the nonlinear state space model for the whole system was achieved. Simulation experi-ments showed that the steady error, delay and flat-headed effect were aroused by the dead-band nonlinearity, and also testified the dissymmetry character of valve-controlled asymmetric cylinder. According to the nonlinear charac-ter, a piecewise PID with dead-band compensation was adopt, and the comparison experiment showed that the pro-posed controller could overcome the affects of dead-band and asymmetric nonlinearities.
2012, 31(9): 1463-1467.
Abstract:
We use the finite element method for linear-elastic reverse deformation to parameterize a complex triangle nesh. To reduce the distortion caused by triangle mesh parameterization, we apply the mesh's intrinsic flexibility naintenance method to flattening the 3D mesh and then take the flattened mesh as the initial iterative mesh to estab-lish the iterative equation with the finite element method for linear-elastic reverse deformation. Through the iterative solution, we obtain the mesh parameterization results that can make the residual internal force of a mesh node or the node displacement satisfy the convergence conditions. The calculation results show that our method can obtain bet-ter parameterization results and is very suitable for computer aided design applications such as re-dividing the me-shes of a complex surface.
We use the finite element method for linear-elastic reverse deformation to parameterize a complex triangle nesh. To reduce the distortion caused by triangle mesh parameterization, we apply the mesh's intrinsic flexibility naintenance method to flattening the 3D mesh and then take the flattened mesh as the initial iterative mesh to estab-lish the iterative equation with the finite element method for linear-elastic reverse deformation. Through the iterative solution, we obtain the mesh parameterization results that can make the residual internal force of a mesh node or the node displacement satisfy the convergence conditions. The calculation results show that our method can obtain bet-ter parameterization results and is very suitable for computer aided design applications such as re-dividing the me-shes of a complex surface.
2012, 31(9): 1468-1473.
Abstract:
Based on finite element with coating were established and software MSC. Marc, the specific simulation model its contact mechanics were analyzed. This paper stress, contact stress and shear stress distribution of cylindrical roller corresponding ing/substrate Young's modulus ratio, different coating thickness and different loading of cylindrical rothng beanng studied the axial equivalent respectively to different coat-by finite element simulation. The simulation results show that the coating cannot reduce or avoid the "sharp edge effect" of stress on the roller end. The axial equivalent stress increases with the increasing of the ratio of coating/substrate Young's modulus. But the ratio of coating/substrate Young's modulus has less effect on the axial contact stress distribution. The peak value of maximum shear stress on coating/substrate increases but the location has no change. With the increasing of coating thickness, the equivalent stress increases, while the contact stress decreases and the surface contact stress decreases. The less thickness may result in the higher interface stress gradient of coating/substrate system. The loading has the same effect on the distribution of equivalent stress and contact stress. And the interface stresses increase with increase of loading.
Based on finite element with coating were established and software MSC. Marc, the specific simulation model its contact mechanics were analyzed. This paper stress, contact stress and shear stress distribution of cylindrical roller corresponding ing/substrate Young's modulus ratio, different coating thickness and different loading of cylindrical rothng beanng studied the axial equivalent respectively to different coat-by finite element simulation. The simulation results show that the coating cannot reduce or avoid the "sharp edge effect" of stress on the roller end. The axial equivalent stress increases with the increasing of the ratio of coating/substrate Young's modulus. But the ratio of coating/substrate Young's modulus has less effect on the axial contact stress distribution. The peak value of maximum shear stress on coating/substrate increases but the location has no change. With the increasing of coating thickness, the equivalent stress increases, while the contact stress decreases and the surface contact stress decreases. The less thickness may result in the higher interface stress gradient of coating/substrate system. The loading has the same effect on the distribution of equivalent stress and contact stress. And the interface stresses increase with increase of loading.
2012, 31(9): 1474-1479.
Abstract:
In this paper, three dynamic balancing performances including inertia force, subsidiary reacting force and inputting torque are considered for the specific problem in dynamic balance optimization. For the driving mech-anism of cold rolling mills, the mathematic model for measuring the degree of dynamic balance optimization is con-structed based on the ideal point method. It could be able to obtain the optimal parameters by proceeding to real-time optimization based on the particle swarm algorithm quickly and accurately. The simulation results indicate that the present method can achieve the optimal value of every dynamic balance performance and effectively solve muhi-objective dynamic balance problems.
In this paper, three dynamic balancing performances including inertia force, subsidiary reacting force and inputting torque are considered for the specific problem in dynamic balance optimization. For the driving mech-anism of cold rolling mills, the mathematic model for measuring the degree of dynamic balance optimization is con-structed based on the ideal point method. It could be able to obtain the optimal parameters by proceeding to real-time optimization based on the particle swarm algorithm quickly and accurately. The simulation results indicate that the present method can achieve the optimal value of every dynamic balance performance and effectively solve muhi-objective dynamic balance problems.
2012, 31(9): 1480-1485.
Abstract:
There is over current in the motor of an ultra-fine mill when it is the computational fluid dynamic technology to analyze the flow field of its working. feeding To solve the problem, we use device. We point out that the problem is caused by the block of particles in the feeding device. We use the orthogonal experiment to carry out nu-merical experiments. The variance analysis results show that outlet pressure of the feeding device, its rotational speed and the interaction between the outlet pressure and th ing continuity. The numerical experiments show that the e feeding volume have the greatest influence on its feed-feeding device works best when its outlet pressure is-1 000 Pa; its feeding volume is0.10 kg/h and its rotational speed is 1 000 r/min.
There is over current in the motor of an ultra-fine mill when it is the computational fluid dynamic technology to analyze the flow field of its working. feeding To solve the problem, we use device. We point out that the problem is caused by the block of particles in the feeding device. We use the orthogonal experiment to carry out nu-merical experiments. The variance analysis results show that outlet pressure of the feeding device, its rotational speed and the interaction between the outlet pressure and th ing continuity. The numerical experiments show that the e feeding volume have the greatest influence on its feed-feeding device works best when its outlet pressure is-1 000 Pa; its feeding volume is0.10 kg/h and its rotational speed is 1 000 r/min.
2012, 31(9): 1486-1489.
Abstract:
Following the locking of harmonic wavelet phase, naxTow-band analysis and the clear expression of time domain, we study the harmonic wavelet adaptive filtering method and give its algorithm. We determine the harmon-ic wavelet from the rotational frequency and filtering bandwidth and extract the dynamic imblance signal that has the same frequency as the rotational speed by calculating the harmonic wavelet and vibration signal in time domain. verify the filtering performance of the harmonic wavelet, we carry out the simulation and on-site spindle dynamic balancing test; the simulation and test results show that: ( 1 ) our harmonic wavelet adaptive fihering method can accurately extract the dynamic imbalance signal; (2) our filtering method is simple and has real time, thus being able to satisfy the requirements for high-precision dynamic balancing test.
Following the locking of harmonic wavelet phase, naxTow-band analysis and the clear expression of time domain, we study the harmonic wavelet adaptive filtering method and give its algorithm. We determine the harmon-ic wavelet from the rotational frequency and filtering bandwidth and extract the dynamic imblance signal that has the same frequency as the rotational speed by calculating the harmonic wavelet and vibration signal in time domain. verify the filtering performance of the harmonic wavelet, we carry out the simulation and on-site spindle dynamic balancing test; the simulation and test results show that: ( 1 ) our harmonic wavelet adaptive fihering method can accurately extract the dynamic imbalance signal; (2) our filtering method is simple and has real time, thus being able to satisfy the requirements for high-precision dynamic balancing test.
2012, 31(9): 1490-1493.
Abstract:
Aiming at the stability of the large reticulated steel shell of the oil tank, the three-dimensional finite ele-ment model of the large reticulated steel shell of the oil tank was established and the finite element modeling process was described at detail. The linear and non-linear buckling process of the large reticulated steel shell was investiga-ted and the limit load of the large reticulated steel shell was obtained. The stability of the large reticulated steel shell for the oil tank was simulated using the established three-dimensional finite element model. The results of sim-ulation provided the theoretic base for the structural and the work condition designs for the large reticulated steel shell.
Aiming at the stability of the large reticulated steel shell of the oil tank, the three-dimensional finite ele-ment model of the large reticulated steel shell of the oil tank was established and the finite element modeling process was described at detail. The linear and non-linear buckling process of the large reticulated steel shell was investiga-ted and the limit load of the large reticulated steel shell was obtained. The stability of the large reticulated steel shell for the oil tank was simulated using the established three-dimensional finite element model. The results of sim-ulation provided the theoretic base for the structural and the work condition designs for the large reticulated steel shell.
2012, 31(9): 1494-1499,1503.
Abstract:
In order to solve the problem of frequent retraction of direction parallel tool pam m me non-convex machining of dental restoration, the generation algorithm of guide lines planning on two-dimension plane is proposed. First of all, the topology relationship between the boundary of machining region and intersections obtained from the parallel line intersected with the machining region should be established, and then the intersections and points in the boundary to form continuous guide lines with less retraction should be linked, according to the corresponding re-lationship. The tool retraction of the resulting tool path generated by the present algorithm is equal to the number of guide lines. The testing results show that the algorithm is stable, fast and reliable, and it can significantly reduce the frequency of tool retraction and improve the processing efficiency of dental restoration.
In order to solve the problem of frequent retraction of direction parallel tool pam m me non-convex machining of dental restoration, the generation algorithm of guide lines planning on two-dimension plane is proposed. First of all, the topology relationship between the boundary of machining region and intersections obtained from the parallel line intersected with the machining region should be established, and then the intersections and points in the boundary to form continuous guide lines with less retraction should be linked, according to the corresponding re-lationship. The tool retraction of the resulting tool path generated by the present algorithm is equal to the number of guide lines. The testing results show that the algorithm is stable, fast and reliable, and it can significantly reduce the frequency of tool retraction and improve the processing efficiency of dental restoration.
2012, 31(9): 1500-1503.
Abstract:
Pattern recognition is key to feature extraction and the effective extraction of features of different patterns is vitally important for the accuracy of pattern recognition. In the high-dimension visualization process, each class of feature vectors has its inherent geometric shape. Therefore, we propose our pattern recognition method that uses the slope relational degree. We use the Iris data set in the UCI machine learning database to analyze the pattern recognition effectiveness, thus obtaining a highly accurate pattern recognition rate. Finally, we apply our pattern recognition method to the fault diagnosis of a rolling bearing and also obtain ideal fault diagnosis results.
Pattern recognition is key to feature extraction and the effective extraction of features of different patterns is vitally important for the accuracy of pattern recognition. In the high-dimension visualization process, each class of feature vectors has its inherent geometric shape. Therefore, we propose our pattern recognition method that uses the slope relational degree. We use the Iris data set in the UCI machine learning database to analyze the pattern recognition effectiveness, thus obtaining a highly accurate pattern recognition rate. Finally, we apply our pattern recognition method to the fault diagnosis of a rolling bearing and also obtain ideal fault diagnosis results.
2012, 31(9): 1504-1507,1511.
Abstract:
The control method for the HEV propulsion system based on the dynamic process was proposed (the DPCM method). The experimental system has been built on the base of the DPCM method. The controlling effect of the DPCM method was validated by the experimental system. Through the vehicle-transmission-test-bed experiment, the driving power under different accelerated rules were compared, which helps to validate that the method advanced in this disserta-tion succeeds in optimizing the dynamic characteristics of the HEV and restricting the energy consumption. The experi-ment proves that the DPCM method can help the optimized target of the control strategy to be implemented.
The control method for the HEV propulsion system based on the dynamic process was proposed (the DPCM method). The experimental system has been built on the base of the DPCM method. The controlling effect of the DPCM method was validated by the experimental system. Through the vehicle-transmission-test-bed experiment, the driving power under different accelerated rules were compared, which helps to validate that the method advanced in this disserta-tion succeeds in optimizing the dynamic characteristics of the HEV and restricting the energy consumption. The experi-ment proves that the DPCM method can help the optimized target of the control strategy to be implemented.
2012, 31(9): 1508-1511.
Abstract:
Aiming at the structural complexity and the uncertainty of parameters' affection on velocity, the three di-mensional model of the U-notch spool valve was built by CFD (Computational Fluid Dynamics) method. Simula-tions were analyzed for different pressures, openings and notch depths; the distribution of velocity field in spool valve and the varying trend of shape and size of high speed area were obtained. The outcome was showed by visual pictures. This study has some instructional meaning for the spool valve design.
Aiming at the structural complexity and the uncertainty of parameters' affection on velocity, the three di-mensional model of the U-notch spool valve was built by CFD (Computational Fluid Dynamics) method. Simula-tions were analyzed for different pressures, openings and notch depths; the distribution of velocity field in spool valve and the varying trend of shape and size of high speed area were obtained. The outcome was showed by visual pictures. This study has some instructional meaning for the spool valve design.
2012, 31(9): 1512-1515,1521.
Abstract:
In order to study the effect of air-gap eccentricity on the rotor system of the ceramic spindle, the varia-tion of air-gap permeance of motorized spindle under the static eccentric was analyzed first, and the expression of the unilateral magnetic pull on the rotor was derived. The characteristics of the unilateral magnetic pull acting on the 170SD30 rotor without inner ceramic motorized spindle were investigated by the electromagnetic-field finite element method. The deformations of ceramic shaft and metal shaft under the unilateral magnetic pull were analyzed and compared based on the finite element three-dimensional model. The results show that the air-gap eccentricity has less impact on the electromagnetic torque, and the unilateral magnetic pull does not change over time when the pole P is greater than 1. Therefore, the effect of the air-gap eccentricity on the performance of the motorized spindle will weaken because of the using ceramic material in motorized spindle.
In order to study the effect of air-gap eccentricity on the rotor system of the ceramic spindle, the varia-tion of air-gap permeance of motorized spindle under the static eccentric was analyzed first, and the expression of the unilateral magnetic pull on the rotor was derived. The characteristics of the unilateral magnetic pull acting on the 170SD30 rotor without inner ceramic motorized spindle were investigated by the electromagnetic-field finite element method. The deformations of ceramic shaft and metal shaft under the unilateral magnetic pull were analyzed and compared based on the finite element three-dimensional model. The results show that the air-gap eccentricity has less impact on the electromagnetic torque, and the unilateral magnetic pull does not change over time when the pole P is greater than 1. Therefore, the effect of the air-gap eccentricity on the performance of the motorized spindle will weaken because of the using ceramic material in motorized spindle.
2012, 31(9): 1516-1521.
Abstract:
In order to solve the problem of cracks for the gear-box of the centrifugal compressor on the condition of blasting experiment, a three-dimensional model of the gear-box was built by UG and HyperMesh softwares. Finite element analysis was performed and the regions with the maximum stress and maximum strain were obtained. The maximum stress of 1 096 MPa was obtained and it couldn't meet the requirements. According to the results of finite element analysis, topology optimization was conducted for the gear-box by OptiStruct software. In the optimization, minimum volume was defined as objective function, the element displacement at the maximum strain location not more than 0.2 mm was used as the constraint function and the element density was adopted as the design variable. The strength of the optimized structure was checked and the maximum stress was reduced to 228 MPa. It was less than the allowable stress of material of the box and satisfied the design requirements. The blasting experiment resuhs verified the success of topology optimization for the gear-box.
In order to solve the problem of cracks for the gear-box of the centrifugal compressor on the condition of blasting experiment, a three-dimensional model of the gear-box was built by UG and HyperMesh softwares. Finite element analysis was performed and the regions with the maximum stress and maximum strain were obtained. The maximum stress of 1 096 MPa was obtained and it couldn't meet the requirements. According to the results of finite element analysis, topology optimization was conducted for the gear-box by OptiStruct software. In the optimization, minimum volume was defined as objective function, the element displacement at the maximum strain location not more than 0.2 mm was used as the constraint function and the element density was adopted as the design variable. The strength of the optimized structure was checked and the maximum stress was reduced to 228 MPa. It was less than the allowable stress of material of the box and satisfied the design requirements. The blasting experiment resuhs verified the success of topology optimization for the gear-box.
2012, 31(9): 1522-1525,1529.
Abstract:
In order to develop an experimental platform simulation robots on-site perception based on virtual reality, simulation of robots to capture parabolic is necessary, then a new method of simulation of robots to capture parabolic is p example to in this paper, and a virtual 3-DOF ( degree of freedom) robots capturing virtual globule is taken as an apply the present method in detail, including forward kinematics equation, inverse kinematics equation, calculation of motion tracking to throw out virtual globule, computation the coordinate of capturing point. Finally, together with the initial position and trajectory planning, the real-time interpolation joint angle for compiling VS (visual studio) program is derived, and experimental test were carried out on the 3-DOF robots platform, the re-suits demonstrate the validity of the algorithm.
In order to develop an experimental platform simulation robots on-site perception based on virtual reality, simulation of robots to capture parabolic is necessary, then a new method of simulation of robots to capture parabolic is p example to in this paper, and a virtual 3-DOF ( degree of freedom) robots capturing virtual globule is taken as an apply the present method in detail, including forward kinematics equation, inverse kinematics equation, calculation of motion tracking to throw out virtual globule, computation the coordinate of capturing point. Finally, together with the initial position and trajectory planning, the real-time interpolation joint angle for compiling VS (visual studio) program is derived, and experimental test were carried out on the 3-DOF robots platform, the re-suits demonstrate the validity of the algorithm.
2012, 31(9): 1526-1529.
Abstract:
In order to reduce the thermal error of the motorized spindle and improve the manufacturing accuracy of NC machine tool, the thermal error model based on multivariate autoregressive method is proposed. This model con-siders not only the relationship between thermal deformation and its lagged value but also the relationship between thermal deformation and the present and lagged value of temperature rise. The linear trends of observed series are eliminated by numerical difference. The order of multivariate autoregressive (MVAR) model is adopted by using Akaike information criterion. The coefficients of the MVAR model are determined by the least square method. The established MVAR model is then used to forecast the thermal error and the experiments have shown the validity and robustness of this model. The results indicate that the displacement-based thermal error autoregressive model has much better accuracy than the temperature-based multiple linear regression model.
In order to reduce the thermal error of the motorized spindle and improve the manufacturing accuracy of NC machine tool, the thermal error model based on multivariate autoregressive method is proposed. This model con-siders not only the relationship between thermal deformation and its lagged value but also the relationship between thermal deformation and the present and lagged value of temperature rise. The linear trends of observed series are eliminated by numerical difference. The order of multivariate autoregressive (MVAR) model is adopted by using Akaike information criterion. The coefficients of the MVAR model are determined by the least square method. The established MVAR model is then used to forecast the thermal error and the experiments have shown the validity and robustness of this model. The results indicate that the displacement-based thermal error autoregressive model has much better accuracy than the temperature-based multiple linear regression model.
2012, 31(9): 1530-1534,1538.
Abstract:
Aim to the puzzledom of complex equipment fauh diagnosis, the Remote Collaborative Fault Diagnosis (RCFD) with multi-diagnostic resources is an R＆D direction. Primary contents include key supporting technologies and system realization of RCFD, and others. Thereinto, key technologies are composed by three issues: active and effective preprocessing on equipment on-site health information, and collaborative process planning of muhi-diag-the last key is-Taking truck nostic resources, which includes diagnostic task allocation and resource optimization two sub-issues, sue is decision fusion on some conflicting conclusion of diagnostic resources based on game theory. chassis system as example, the architecture and engineering application of RCFD has also expounded. Finnally, further studying points of RCFD Key words: remote cooperative are indicated. diagnosis local information preprocessing; task allocation; decision fusionfurther studying points of RCFD are indicated.
Aim to the puzzledom of complex equipment fauh diagnosis, the Remote Collaborative Fault Diagnosis (RCFD) with multi-diagnostic resources is an R＆D direction. Primary contents include key supporting technologies and system realization of RCFD, and others. Thereinto, key technologies are composed by three issues: active and effective preprocessing on equipment on-site health information, and collaborative process planning of muhi-diag-the last key is-Taking truck nostic resources, which includes diagnostic task allocation and resource optimization two sub-issues, sue is decision fusion on some conflicting conclusion of diagnostic resources based on game theory. chassis system as example, the architecture and engineering application of RCFD has also expounded. Finnally, further studying points of RCFD Key words: remote cooperative are indicated. diagnosis local information preprocessing; task allocation; decision fusionfurther studying points of RCFD are indicated.
2012, 31(9): 1535-1538.
Abstract:
A hydraulic synchronization valve is an important device for hydraulic synchronization driving, and its conflux conditions such as conflux speed and synchronous accuracy decide its performance. After analyzing its con-struction and conflux mechanism, we establish its model with the AMESim software. With the actual parameters of a certain model of hydraulic synchronization valve, we set up various parameters of the model and verify its correct-ness. Then we analyze the effects of spring stiffness, the diameter of spring seat and the default opening area of the variable orifices on the conflux speed synchronization accuracy of the hydraulic synchronization valve.
A hydraulic synchronization valve is an important device for hydraulic synchronization driving, and its conflux conditions such as conflux speed and synchronous accuracy decide its performance. After analyzing its con-struction and conflux mechanism, we establish its model with the AMESim software. With the actual parameters of a certain model of hydraulic synchronization valve, we set up various parameters of the model and verify its correct-ness. Then we analyze the effects of spring stiffness, the diameter of spring seat and the default opening area of the variable orifices on the conflux speed synchronization accuracy of the hydraulic synchronization valve.
2012, 31(9): 1539-1542,1548.
Abstract:
The vibration signals of bearings are usually typical fault samples in reality. Therefore we propose a tion (LMD) approximate entropy and the support vector non-stationary and it is difficult to obtain a large number of fault diagnosis method that uses the local mean decomposi-machine (SVM). We decompose the original non-stationa-ry acceleration vibration signals into several stationary production functions (PFs). Because the approximate entro-py values of vibration signals in different frequency bands change when faults occur in bearings, we can judge whether a fault occurs and decide its type by calculating the approximate entropy and can establish the SVM by using as its input the approximate entropy features extracted from the PFs that contain the major information on faults. Experimental results show that our diagnosis method can effectively diagnose faults of bearings.
The vibration signals of bearings are usually typical fault samples in reality. Therefore we propose a tion (LMD) approximate entropy and the support vector non-stationary and it is difficult to obtain a large number of fault diagnosis method that uses the local mean decomposi-machine (SVM). We decompose the original non-stationa-ry acceleration vibration signals into several stationary production functions (PFs). Because the approximate entro-py values of vibration signals in different frequency bands change when faults occur in bearings, we can judge whether a fault occurs and decide its type by calculating the approximate entropy and can establish the SVM by using as its input the approximate entropy features extracted from the PFs that contain the major information on faults. Experimental results show that our diagnosis method can effectively diagnose faults of bearings.
2012, 31(9): 1543-1548.
Abstract:
For the complicated turbulent flow in the air film of air bearings, there is no analytical method to solve the Reynold equations. With the numerical method that uses the Fluent software's 3D standard turbulent viscosity κ-εmodel, we analyze the performance of the aerostatic plane bearing with 4 ×4 orifice array and obtain its key pa-rameters such as load capacity, mass flux, pressure distribution and velocity distribution of the coupling air film. The simulation results reveal the air film's pressure distribution in the orifice array: the more orifice units produce the stronger pressure coupling, and the larger the pressure value is; the coupling of the orifices in the array can be obtained from the accumulative distribution of the pressure and velocity of the air film. The effectiveness of the sim-ulation results are verified by the physical model test. The exploration results are useful for optimizing the design of air bearings and identifying the analytical model of air film's pressure distribution in an orifice array.
For the complicated turbulent flow in the air film of air bearings, there is no analytical method to solve the Reynold equations. With the numerical method that uses the Fluent software's 3D standard turbulent viscosity κ-εmodel, we analyze the performance of the aerostatic plane bearing with 4 ×4 orifice array and obtain its key pa-rameters such as load capacity, mass flux, pressure distribution and velocity distribution of the coupling air film. The simulation results reveal the air film's pressure distribution in the orifice array: the more orifice units produce the stronger pressure coupling, and the larger the pressure value is; the coupling of the orifices in the array can be obtained from the accumulative distribution of the pressure and velocity of the air film. The effectiveness of the sim-ulation results are verified by the physical model test. The exploration results are useful for optimizing the design of air bearings and identifying the analytical model of air film's pressure distribution in an orifice array.
