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RSS2013 Vol. 32, No. 10
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2013, 32(10): 1406-1411.
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Abstract:
The study of POGO vibration requires that the study of the natural frequency and the transfer function of the propelling flow system in a liquid rocket should be under all flow parameters.We use the LRC equivalent circuit analysis method to make sure that each element of the propelling flow system is equivalent to inductance,resistance,and capacitance that makes up the circuit.The mathematic models of the propelling flow system in the liquid rocket are perfected,and the transfer function expressions of the propelling flow system are elicited by means of the network function that accurately solves the natural frequency of the propelling flow system.Finally,from the statistic point of view,we use the correlation coefficient method to study the influence of all flow parameters on the natural frequency and the major influence of liquid flow parameters on the natural frequency of a liquid propelling flow system in a liquid rocket.
The study of POGO vibration requires that the study of the natural frequency and the transfer function of the propelling flow system in a liquid rocket should be under all flow parameters.We use the LRC equivalent circuit analysis method to make sure that each element of the propelling flow system is equivalent to inductance,resistance,and capacitance that makes up the circuit.The mathematic models of the propelling flow system in the liquid rocket are perfected,and the transfer function expressions of the propelling flow system are elicited by means of the network function that accurately solves the natural frequency of the propelling flow system.Finally,from the statistic point of view,we use the correlation coefficient method to study the influence of all flow parameters on the natural frequency and the major influence of liquid flow parameters on the natural frequency of a liquid propelling flow system in a liquid rocket.
2013, 32(10): 1412-1416.
Abstract:
Water hydraulic piloted solenoid relief valve is one of the key components in high-precision and deep-see remote control.The structure of relief valve and its work principle is briefly introduced by taking full account of the physical and chemical properties of seawater,and the main design points of pure water hydraulic relief valve are proposed.According to the physical properties of medium water and the results of friction and wear tests,the key parts materials of relief valve are selected.Experimental system of pure water hydraulic relief valve is designed with reference to the oil hydraulic relief valve,and both the static characteristics and dynamic characteristics tests of the pure water hydraulic relief valve is conducted.From the tests it can be seen that the design pressure range of relief valve is 0.5 MPa~9 MPa,and its overshoot of pressure is low,dynamic response is fast.
Water hydraulic piloted solenoid relief valve is one of the key components in high-precision and deep-see remote control.The structure of relief valve and its work principle is briefly introduced by taking full account of the physical and chemical properties of seawater,and the main design points of pure water hydraulic relief valve are proposed.According to the physical properties of medium water and the results of friction and wear tests,the key parts materials of relief valve are selected.Experimental system of pure water hydraulic relief valve is designed with reference to the oil hydraulic relief valve,and both the static characteristics and dynamic characteristics tests of the pure water hydraulic relief valve is conducted.From the tests it can be seen that the design pressure range of relief valve is 0.5 MPa~9 MPa,and its overshoot of pressure is low,dynamic response is fast.
2013, 32(10): 1417-1421.
Abstract:
Vibration of the spoke is an important reason for the invalidation of aero-gear,and it is significant to alleviate the vibration of the spoke by adding the additional damping bowl.By using the equivalent linearization method,transforming dry friction into the correction of system characteristic parameters,and adding the equivalent spring unit and the equivalent damping unit between the contact surfaces,an equivalent model of composite structure is established in this paper.By determining the dynamic loads of the size and loading position of the different moments,and using APDL(Ansys Programming Design Language) programming loading dynamic load into sections of spiral bevel gear,finally,the dynamic responses of equivalent model of the composite structure are solved by ANSYS,and this method provides a reference for structural design of vibration reduction.
Vibration of the spoke is an important reason for the invalidation of aero-gear,and it is significant to alleviate the vibration of the spoke by adding the additional damping bowl.By using the equivalent linearization method,transforming dry friction into the correction of system characteristic parameters,and adding the equivalent spring unit and the equivalent damping unit between the contact surfaces,an equivalent model of composite structure is established in this paper.By determining the dynamic loads of the size and loading position of the different moments,and using APDL(Ansys Programming Design Language) programming loading dynamic load into sections of spiral bevel gear,finally,the dynamic responses of equivalent model of the composite structure are solved by ANSYS,and this method provides a reference for structural design of vibration reduction.
2013, 32(10): 1422-1427.
Abstract:
Aiming at the characteristic that actual measured points obtained from coordinate measuring machine(CMM) were not located on the same ideal plane precisely due to the existence of measurement errors,in order to improve the evaluation accuracy of circularity errors in three-dimensional space,the least squares plane based on the center point of arithmetic average of the measured points set(LSPBC) was proposed and the mathematical model was derived,according to computational geometry and errors theory.Then three circularity error evaluation methods with minimum circumscribed circle,maximum inscribed circle and minimum zone circle in the national standard were extended into the three-dimensional space.On the basis of them,the first two kinds of methods were improved; the mathematical models and evaluation steps of the three kinds of methods were built.Finally,the validity of proposed methods was verified through numerical experiments.
Aiming at the characteristic that actual measured points obtained from coordinate measuring machine(CMM) were not located on the same ideal plane precisely due to the existence of measurement errors,in order to improve the evaluation accuracy of circularity errors in three-dimensional space,the least squares plane based on the center point of arithmetic average of the measured points set(LSPBC) was proposed and the mathematical model was derived,according to computational geometry and errors theory.Then three circularity error evaluation methods with minimum circumscribed circle,maximum inscribed circle and minimum zone circle in the national standard were extended into the three-dimensional space.On the basis of them,the first two kinds of methods were improved; the mathematical models and evaluation steps of the three kinds of methods were built.Finally,the validity of proposed methods was verified through numerical experiments.
2013, 32(10): 1428-1432.
Abstract:
Because of the complexity of the shaped surface structure of the critical and high-performance work pieces of high-end equipment,their requirement is very high.The main requirement is about their performance and processing,requiring the integration of performance with geometric parameters.These high performance work pieces have the characters of complex moulding surface and are difficult to process their raw materials,their material deformation having big resistance.The structure properties are very sensitive to parameters of thermal processing time,temperature,strength and so on.So when the work peieces are deformed,it is very difficult to ensure their structure properties,which are affected by several factors like material,thermal processing,geometric shape and so on,causing the high defective rate in production and low efficiency in machining.This paper comes up with a solution to set up an integrated full life cycle quality information model for high performance work pieces,whose idea changes from dispersive quality information processing to integrated manufacturing process oriented quality information management.The paper also studies the mapping and integration of quality data with quality inspection standards,thus realizing the management and control of function quality in the deformation processes.
Because of the complexity of the shaped surface structure of the critical and high-performance work pieces of high-end equipment,their requirement is very high.The main requirement is about their performance and processing,requiring the integration of performance with geometric parameters.These high performance work pieces have the characters of complex moulding surface and are difficult to process their raw materials,their material deformation having big resistance.The structure properties are very sensitive to parameters of thermal processing time,temperature,strength and so on.So when the work peieces are deformed,it is very difficult to ensure their structure properties,which are affected by several factors like material,thermal processing,geometric shape and so on,causing the high defective rate in production and low efficiency in machining.This paper comes up with a solution to set up an integrated full life cycle quality information model for high performance work pieces,whose idea changes from dispersive quality information processing to integrated manufacturing process oriented quality information management.The paper also studies the mapping and integration of quality data with quality inspection standards,thus realizing the management and control of function quality in the deformation processes.
2013, 32(10): 1433-1436.
Abstract:
In order to measure the transmission loss(TL) of muffler in the acoustic symmetrical characteristic rapidly,a new method utilizing four microphones and one-load was put forward.The couple of downstream transmission reflection wave to the upstream sound field could be eliminated with the reference of mathematical relationship of acoustic transfer matrix.By using the boundary element method,the TL virtual measurement of a Helmholtz resonant muffler was performed and the new method was validated.Comparing with the traditional methods,the TL could be acquired by one measurement and the advantages such as the simple measuring equipments,fast speed,high precision,easy operation,etc were achieved.
In order to measure the transmission loss(TL) of muffler in the acoustic symmetrical characteristic rapidly,a new method utilizing four microphones and one-load was put forward.The couple of downstream transmission reflection wave to the upstream sound field could be eliminated with the reference of mathematical relationship of acoustic transfer matrix.By using the boundary element method,the TL virtual measurement of a Helmholtz resonant muffler was performed and the new method was validated.Comparing with the traditional methods,the TL could be acquired by one measurement and the advantages such as the simple measuring equipments,fast speed,high precision,easy operation,etc were achieved.
2013, 32(10): 1437-1440.
Abstract:
Based on computer vision technology,an automatic detection and analysis of the display performance of image display device under the vibrational environment was presented.Firstly,we presented the overall structure of the hardware components and software of the prototype and described the design of the hardware system and the selection of the hardware devices type.Then,we focused on the key algorithms of video motion compensation under camera-moving conditions,detecting and extracting the straight line with sub-pixel accuracy.The software prototype was developed with C ++.The experimental results showed that the system can capture images steadily,achieve the sub-pixel analysis of images and output detection results.
Based on computer vision technology,an automatic detection and analysis of the display performance of image display device under the vibrational environment was presented.Firstly,we presented the overall structure of the hardware components and software of the prototype and described the design of the hardware system and the selection of the hardware devices type.Then,we focused on the key algorithms of video motion compensation under camera-moving conditions,detecting and extracting the straight line with sub-pixel accuracy.The software prototype was developed with C ++.The experimental results showed that the system can capture images steadily,achieve the sub-pixel analysis of images and output detection results.
2013, 32(10): 1441-1445.
Abstract:
In order to improve the accuracy reliability of a transmission system for numerical control(NC) machine tools,fuzzy comprehensive assessment matrix(FCAM) was applied to allocate the accuracy reliability of NC machine tool feed system whose reliability indexes can be qualitative,quantitative and multi-hierarchic.A fuzzy analytic hierarchy process(AHP) with five-scale was proposed.Many influence factors were considered and endowed with different weight according to the influence degree.A structural model of AHP is proposed for NC machine tools,which used interval number instead of fuzzy assessment matrix to express uncertain information.It can make use of expert's experience and the field test information comprehensively.A heavy duty machine tool was taken as example to illustrate the application of this method.
In order to improve the accuracy reliability of a transmission system for numerical control(NC) machine tools,fuzzy comprehensive assessment matrix(FCAM) was applied to allocate the accuracy reliability of NC machine tool feed system whose reliability indexes can be qualitative,quantitative and multi-hierarchic.A fuzzy analytic hierarchy process(AHP) with five-scale was proposed.Many influence factors were considered and endowed with different weight according to the influence degree.A structural model of AHP is proposed for NC machine tools,which used interval number instead of fuzzy assessment matrix to express uncertain information.It can make use of expert's experience and the field test information comprehensively.A heavy duty machine tool was taken as example to illustrate the application of this method.
2013, 32(10): 1446-1450.
Abstract:
This paper reveals that obvious errors exist between simulated variance and settled variance,and then analyzes the causes of those errors.The effects of initial frequency and cut-off frequency on the simulated variance are ascertained with different turbulent length/wind speed ratio,then the recommended initial frequency and cut-off frequency are given,and a method is developed to reduce these effects.Using the improved Kaimal spectra and stationary random method,stochastic wind data at hub height is simulated.The wind time-series show that the simulated wind velocity satisfies statistical standard deviation demand,and simulated spectra well conform to the target power spectral.
This paper reveals that obvious errors exist between simulated variance and settled variance,and then analyzes the causes of those errors.The effects of initial frequency and cut-off frequency on the simulated variance are ascertained with different turbulent length/wind speed ratio,then the recommended initial frequency and cut-off frequency are given,and a method is developed to reduce these effects.Using the improved Kaimal spectra and stationary random method,stochastic wind data at hub height is simulated.The wind time-series show that the simulated wind velocity satisfies statistical standard deviation demand,and simulated spectra well conform to the target power spectral.
2013, 32(10): 1451-1455.
Abstract:
Edge chipping fracture in machining of brittle and hard materials is easy to form.It could seriously affect the products quality and even would lead products below standard.The conventional control method is to decrease cutting force with lower machining parameters.But the control effect was not ideal.In this paper,the edge chipping fracture mechanisms in machining brittle and hard materials has been studied in depth,and a model with three levels of influencing factors was proposed.The rationality of the present model and the effectiveness of the control method were proved by machining a typical K9 glass part.The mechanisms of edge chipping fracture in drilling process of diamond cutter were analyzed selectively.The workpiece structure and cutting force distribution were changed by additional supports.Several basic principles of additional supports were discussed.Finally,the basic idea had been extended to machining complex parts of brittle materials and it worked well.
Edge chipping fracture in machining of brittle and hard materials is easy to form.It could seriously affect the products quality and even would lead products below standard.The conventional control method is to decrease cutting force with lower machining parameters.But the control effect was not ideal.In this paper,the edge chipping fracture mechanisms in machining brittle and hard materials has been studied in depth,and a model with three levels of influencing factors was proposed.The rationality of the present model and the effectiveness of the control method were proved by machining a typical K9 glass part.The mechanisms of edge chipping fracture in drilling process of diamond cutter were analyzed selectively.The workpiece structure and cutting force distribution were changed by additional supports.Several basic principles of additional supports were discussed.Finally,the basic idea had been extended to machining complex parts of brittle materials and it worked well.
2013, 32(10): 1456-1460.
Abstract:
Flywheel rotor is a very important component in the flywheel energy storage system(FESS).The key factors of rotor,such as rotor materials,geometry and fabrication process,have direct influence on the performance of FESS.This paper was concerned with influences of these factors on the Von Mises equivalent stress distribution of the metal hub and the radial stress distribution of the composite materials rim by using the 3D finite element method.The fabrication process of the flywheel rotor was determined based on the analysis results: T800H carbon fiber composite materials rim was formed by winding on the 7050 aluminum alloy hub.The flywheel rotor developed can operate normally.
Flywheel rotor is a very important component in the flywheel energy storage system(FESS).The key factors of rotor,such as rotor materials,geometry and fabrication process,have direct influence on the performance of FESS.This paper was concerned with influences of these factors on the Von Mises equivalent stress distribution of the metal hub and the radial stress distribution of the composite materials rim by using the 3D finite element method.The fabrication process of the flywheel rotor was determined based on the analysis results: T800H carbon fiber composite materials rim was formed by winding on the 7050 aluminum alloy hub.The flywheel rotor developed can operate normally.
2013, 32(10): 1461-1465.
Abstract:
In this paper,the structural design optimization method for a cylindrical grinding machine tool bed structure is studied so as to make it possible to obtain an eco-efficient structure.The optimum design process includes three steps in the following.Firstly,the static stiffness of the original bed is analyzed by structural analysis-finite element method.And several defects are found and specific improvement approaches are presented.As a result,a bed structure is improved.The higher the stiffness,the lighter the weight is.Secondly,the positions of the stiffener plates inside the modified bed structure are optimized by topology optimization method.The optimization result shows that four stiffener plates should be located inside the bed structure.Finally,the sizing optimization is implemented to achieve the lightest structure.Several dimension variables that contribute to the mass and strain energy of the bed structure more critically are selected by using the sensitivity analysis.And the model is constructed to optimize the bed structure.The sequential quadratic programming algorithm is adopted to solve the present problem,and the optimal bed structure is obtained.By reanalyzing the optimized bed structure,the stiffness is 2.49 times better than the original one,and the weight reduces by 22.14%,in which the optimization design in high stiffness and light weight is realized.
In this paper,the structural design optimization method for a cylindrical grinding machine tool bed structure is studied so as to make it possible to obtain an eco-efficient structure.The optimum design process includes three steps in the following.Firstly,the static stiffness of the original bed is analyzed by structural analysis-finite element method.And several defects are found and specific improvement approaches are presented.As a result,a bed structure is improved.The higher the stiffness,the lighter the weight is.Secondly,the positions of the stiffener plates inside the modified bed structure are optimized by topology optimization method.The optimization result shows that four stiffener plates should be located inside the bed structure.Finally,the sizing optimization is implemented to achieve the lightest structure.Several dimension variables that contribute to the mass and strain energy of the bed structure more critically are selected by using the sensitivity analysis.And the model is constructed to optimize the bed structure.The sequential quadratic programming algorithm is adopted to solve the present problem,and the optimal bed structure is obtained.By reanalyzing the optimized bed structure,the stiffness is 2.49 times better than the original one,and the weight reduces by 22.14%,in which the optimization design in high stiffness and light weight is realized.
2013, 32(10): 1466-1470.
Abstract:
Multiscale wavelet analysis to image edge detection is a current research focus.The edge of grain is the basic feature in the ferrography image,providing important characteristic parameters for ferrography image's feature extraction and playing a very important role in failure analysis based on ferrographic analysis technology.In this article,the lifting wavelet transforms is used to edge detection of ferrograghy image.First,the color image of ferrography is segmented into RGB single channel images,preconditioning each single image and separating grains from the background by histogram and image depth conversion; Then,D4 lifting wavelet is used to each single channel image,extracting pixels of edge from the sub-image in wavelet domain by threshold; Lastly,the final edge images are obtained through OR operation.Compared with the Soble algorithm and the Canny algorithm,this article's algorithm is more efficient at reducing noise for the edge detection of ferrography image.
Multiscale wavelet analysis to image edge detection is a current research focus.The edge of grain is the basic feature in the ferrography image,providing important characteristic parameters for ferrography image's feature extraction and playing a very important role in failure analysis based on ferrographic analysis technology.In this article,the lifting wavelet transforms is used to edge detection of ferrograghy image.First,the color image of ferrography is segmented into RGB single channel images,preconditioning each single image and separating grains from the background by histogram and image depth conversion; Then,D4 lifting wavelet is used to each single channel image,extracting pixels of edge from the sub-image in wavelet domain by threshold; Lastly,the final edge images are obtained through OR operation.Compared with the Soble algorithm and the Canny algorithm,this article's algorithm is more efficient at reducing noise for the edge detection of ferrography image.
2013, 32(10): 1471-1475.
Abstract:
The model of transimission mechanism is built on the base of the operating principle of active front steering system(abbreviated to AFS).According to steady-state yaw velocity gain of steering system,appropriate fixed yaw velocity gain is chose to design transmission ratio curve of AFS.Based on this curve,superposition angle curve of steering shaft is established.The co-simulation model of the car with AFS is developed which realizes active front steering through controlling the motor according to the superposition angle curve.The co-simulation results show that the design method of AFS transmission ratio is reasonable and effective.
The model of transimission mechanism is built on the base of the operating principle of active front steering system(abbreviated to AFS).According to steady-state yaw velocity gain of steering system,appropriate fixed yaw velocity gain is chose to design transmission ratio curve of AFS.Based on this curve,superposition angle curve of steering shaft is established.The co-simulation model of the car with AFS is developed which realizes active front steering through controlling the motor according to the superposition angle curve.The co-simulation results show that the design method of AFS transmission ratio is reasonable and effective.
2013, 32(10): 1476-1480.
Abstract:
For the structural hybrid reliability analysis of implicit limit state equation,the support vector regression theory is introduced,and a high accuracy approximate limit state equation is obtained in this paper.Combined with probabilistic and non-probabilistic hybrid reliability model and the advanced first-order second moment method,a new method for structural hybrid reliability analysis is presented on the basis of support vector regression.Finally,the feasibility and validity of the method are verified though hybrid reliability analysis of a cantilever beam and a plane truss structure.The examples show that the results of the new method agree well with those by the Monte Carlo method,when the structures include both probabilistic and non-probabilistic parameters.This method has a higher computational precision and also has certain practical value for engineering problems.
For the structural hybrid reliability analysis of implicit limit state equation,the support vector regression theory is introduced,and a high accuracy approximate limit state equation is obtained in this paper.Combined with probabilistic and non-probabilistic hybrid reliability model and the advanced first-order second moment method,a new method for structural hybrid reliability analysis is presented on the basis of support vector regression.Finally,the feasibility and validity of the method are verified though hybrid reliability analysis of a cantilever beam and a plane truss structure.The examples show that the results of the new method agree well with those by the Monte Carlo method,when the structures include both probabilistic and non-probabilistic parameters.This method has a higher computational precision and also has certain practical value for engineering problems.
2013, 32(10): 1481-1483.
Abstract:
The topology optimization design may be helpful in improving performance of the structure and reducing its weight.Therefore,the engineering application of topology optimization is very important study object.In this paper,according to the evolutionary structural optimization(Abbr.ESO) idea,the ESO model based on the selection logical method is developed to delete elements under the stress constraints.And the optimization software programming processor is introduced and the APDL software for structural optimization principle is programmed on the ANSYS platform.A classical example of 2D structure verifies feasibility of this topology optimization method,and another example of 3D structure verifies its universal.Practical application shows the method in this paper provides a new way in application of ANSYS software platform to evolutionary structural optimization.
The topology optimization design may be helpful in improving performance of the structure and reducing its weight.Therefore,the engineering application of topology optimization is very important study object.In this paper,according to the evolutionary structural optimization(Abbr.ESO) idea,the ESO model based on the selection logical method is developed to delete elements under the stress constraints.And the optimization software programming processor is introduced and the APDL software for structural optimization principle is programmed on the ANSYS platform.A classical example of 2D structure verifies feasibility of this topology optimization method,and another example of 3D structure verifies its universal.Practical application shows the method in this paper provides a new way in application of ANSYS software platform to evolutionary structural optimization.
2013, 32(10): 1484-1487.
Abstract:
To calculate the joint clearance of retracting mechanism by using the position parameters of landing gear,the model for position calculation of landing gear with joint clearance is established based on continuous contact model.To solve the problem the position parameters of landing gear on ideal status,the optimized variables are adopted and then a multi-objective optimal model is established by performing the minimum differences of two groups of calculation data of the joint clearance of retracting mechanism as the optimization goal,from the abovementioned model the optimal value of the position parameters of landing gear on ideal status are calculated,so as to solve the calculating problem in the joint clearance of retracting mechanism.The calculation example shows that the method for calculating the joint clearance of landing gear retracting mechanism is feasible and effective.
To calculate the joint clearance of retracting mechanism by using the position parameters of landing gear,the model for position calculation of landing gear with joint clearance is established based on continuous contact model.To solve the problem the position parameters of landing gear on ideal status,the optimized variables are adopted and then a multi-objective optimal model is established by performing the minimum differences of two groups of calculation data of the joint clearance of retracting mechanism as the optimization goal,from the abovementioned model the optimal value of the position parameters of landing gear on ideal status are calculated,so as to solve the calculating problem in the joint clearance of retracting mechanism.The calculation example shows that the method for calculating the joint clearance of landing gear retracting mechanism is feasible and effective.
2013, 32(10): 1488-1491.
Abstract:
This paper studies the navigation method of behavior dynamics in mobile robot.First,this paper analyzes the existing problems in practical applications which would cause the risk of collision or influence the navigation performance,and puts forward corresponding solutions.To solve the problem that the robot can only be used in low speed navigation because the method's linear velocity control law is under restrictions,this paper analyzes the constraint relation between direction angle and linear velocity in robot navigation by using the geometrical description method,proposes direction angle follow control.The behavior dynamics with direction angle follow control can overcome robot's speed limit,and guarantee the safe navigation under increasing robot's linear velocity.
This paper studies the navigation method of behavior dynamics in mobile robot.First,this paper analyzes the existing problems in practical applications which would cause the risk of collision or influence the navigation performance,and puts forward corresponding solutions.To solve the problem that the robot can only be used in low speed navigation because the method's linear velocity control law is under restrictions,this paper analyzes the constraint relation between direction angle and linear velocity in robot navigation by using the geometrical description method,proposes direction angle follow control.The behavior dynamics with direction angle follow control can overcome robot's speed limit,and guarantee the safe navigation under increasing robot's linear velocity.
2013, 32(10): 1492-1498.
Abstract:
The natural frequencies and vibration shapes of a wind turbine are important parameters for wind turbine design.According to its structure,it is simplified as a combination of no mass beam elements and lumped mass inertia elements,and the transfer matrices of these two elements are generated.With these,the transfer matrix of a whole wind turbine can be obtained and has three inputs as blade tips and one output as the bottom of tower.The natural frequencies and mode shapes of a 5MW onshore wind turbine are analyzed.The analysis results are accurate and reasonable.Compared with the finite element method,the transfer matrix method has the ease of model establishment,fast calculation and no complicated posterior process.
The natural frequencies and vibration shapes of a wind turbine are important parameters for wind turbine design.According to its structure,it is simplified as a combination of no mass beam elements and lumped mass inertia elements,and the transfer matrices of these two elements are generated.With these,the transfer matrix of a whole wind turbine can be obtained and has three inputs as blade tips and one output as the bottom of tower.The natural frequencies and mode shapes of a 5MW onshore wind turbine are analyzed.The analysis results are accurate and reasonable.Compared with the finite element method,the transfer matrix method has the ease of model establishment,fast calculation and no complicated posterior process.
2013, 32(10): 1499-1504.
Abstract:
In the light of the features of high-speed train bearing such as the slow deterioration process and the smooth deterioration path,the stochastic performance deterioration process model is established through viewing the unknown parameters of the Wiener process as stochastic variables.According to the size of the bearing relative temperature(relative to the environmental temperature) performance deterioration amplitude and the engineering experiences,the reasonable deterioration path model is determined and the reliability function of bearing life is finally obtained.The feasibility of proposed method is proved and the bearing life reliability evaluation can be completed by analyzing a bearing testing data in the case of the minimum sample and zero-failure.Thus the method provides a guide for the high-speed train bearing reliability evaluation problem.
In the light of the features of high-speed train bearing such as the slow deterioration process and the smooth deterioration path,the stochastic performance deterioration process model is established through viewing the unknown parameters of the Wiener process as stochastic variables.According to the size of the bearing relative temperature(relative to the environmental temperature) performance deterioration amplitude and the engineering experiences,the reasonable deterioration path model is determined and the reliability function of bearing life is finally obtained.The feasibility of proposed method is proved and the bearing life reliability evaluation can be completed by analyzing a bearing testing data in the case of the minimum sample and zero-failure.Thus the method provides a guide for the high-speed train bearing reliability evaluation problem.
2013, 32(10): 1505-1508.
Abstract:
Because of the flexible question of rapier loom at high speed,this paper was considered only the flexibility of the crank by changing the crank material.With the method of ANSYS-ADAMS co-simulation,corresponding neutral documents generated in ANSYS were imported into ADAMS for simulation to receive the motion curves of sword belt.Through the analysis and comparison,the relationship of changing the crank material and the motion curves of sword belt were found.The simulation results show that,in consideration of the flexible components,rational selection of crank material can greatly reduce the impact on spatial four bar linkage weft insertion mechanism,thereby enhance the quality of the fabric.
Because of the flexible question of rapier loom at high speed,this paper was considered only the flexibility of the crank by changing the crank material.With the method of ANSYS-ADAMS co-simulation,corresponding neutral documents generated in ANSYS were imported into ADAMS for simulation to receive the motion curves of sword belt.Through the analysis and comparison,the relationship of changing the crank material and the motion curves of sword belt were found.The simulation results show that,in consideration of the flexible components,rational selection of crank material can greatly reduce the impact on spatial four bar linkage weft insertion mechanism,thereby enhance the quality of the fabric.
2013, 32(10): 1509-1513.
Abstract:
On the rotating wearing experimental set-up,we perform the interactive erosion and cavitation wearing experiments of three phases under different environmental pressures.We use the computational fluid dynamics(CFD) method to simulate the working conditions of a hydraulic turbine under different environmental pressures in the three phases of vapor,liquid and solid.The flow fields and their characteristics on the turntable surface are numerically analyzed.The analysis results show that under four different environmental pressures,when pressure increases,interactive wear weight loss decreases linearly,namely the interactive wear is more slight; the overlay area between total pressure contours and vapor phase volume fraction contours is in accord with the interactive wear surface morphology of the test specimen of test pieces,namely the numerical results coincide better,thus proving that the theoretical analysis is reasonable.
On the rotating wearing experimental set-up,we perform the interactive erosion and cavitation wearing experiments of three phases under different environmental pressures.We use the computational fluid dynamics(CFD) method to simulate the working conditions of a hydraulic turbine under different environmental pressures in the three phases of vapor,liquid and solid.The flow fields and their characteristics on the turntable surface are numerically analyzed.The analysis results show that under four different environmental pressures,when pressure increases,interactive wear weight loss decreases linearly,namely the interactive wear is more slight; the overlay area between total pressure contours and vapor phase volume fraction contours is in accord with the interactive wear surface morphology of the test specimen of test pieces,namely the numerical results coincide better,thus proving that the theoretical analysis is reasonable.
2013, 32(10): 1514-1517.
Abstract:
The changed diameter mechanism in the in-pipe clearing robot influnence on motion performances and drive performances,the mechanism optimzation can solve mechanism systhesis probleme efficiently.on the base of analysing kinematics and mechanics,multi-objective dimension synthesis of the changing diameter mechanism is put forword.Using force on the key part and movement range of the drive part of the changed diameter mechanism as optimization objectives,multi-objective optimization Pareto optimal solutions using non-dominated sorting genetic algorithm Ⅱ(NSGA-Ⅱ) is solved.The optimization results show that the optimal changed diameter mechanism in the in-pipe clearing robot has a good mechanics performance and range of movement.Without repeating calculation,the optimization results which meet different requirements is selected according to design requriements and engineering experiences.
The changed diameter mechanism in the in-pipe clearing robot influnence on motion performances and drive performances,the mechanism optimzation can solve mechanism systhesis probleme efficiently.on the base of analysing kinematics and mechanics,multi-objective dimension synthesis of the changing diameter mechanism is put forword.Using force on the key part and movement range of the drive part of the changed diameter mechanism as optimization objectives,multi-objective optimization Pareto optimal solutions using non-dominated sorting genetic algorithm Ⅱ(NSGA-Ⅱ) is solved.The optimization results show that the optimal changed diameter mechanism in the in-pipe clearing robot has a good mechanics performance and range of movement.Without repeating calculation,the optimization results which meet different requirements is selected according to design requriements and engineering experiences.
2013, 32(10): 1518-1523.
Abstract:
New kind of composite actuator is designed by rubber and piezoelectric materials which as the active part to isolate the platform's six-degree of freedom(6-DOF) vibrations,and the rubber isolate the high frequency distribution when the piezoelectric stack isolates the low frequency interference actively.Because of the piezoelectric micro-vibration isolation platform's distribution and the actuators' perturbation,which would lead to the platform's actual isolation effect could not achieve the simulation effect and does not be considered when designs the piezoelectric micro-vibration isolation platform's robust controllers.Based on the Riccati inequality,through the method of state feedback control,designed a new Algorithms of Robust Controller which contends compromise factors' affection to isolate the low frequency distribution,and those factors' affection are replaced by all kinds of platform model's parameters distribution.The simulation and experiment results show that the amplitude is reduced 97.4% by simulation when 93.9% by test.The Algorithm is better than the simple robust controller.
New kind of composite actuator is designed by rubber and piezoelectric materials which as the active part to isolate the platform's six-degree of freedom(6-DOF) vibrations,and the rubber isolate the high frequency distribution when the piezoelectric stack isolates the low frequency interference actively.Because of the piezoelectric micro-vibration isolation platform's distribution and the actuators' perturbation,which would lead to the platform's actual isolation effect could not achieve the simulation effect and does not be considered when designs the piezoelectric micro-vibration isolation platform's robust controllers.Based on the Riccati inequality,through the method of state feedback control,designed a new Algorithms of Robust Controller which contends compromise factors' affection to isolate the low frequency distribution,and those factors' affection are replaced by all kinds of platform model's parameters distribution.The simulation and experiment results show that the amplitude is reduced 97.4% by simulation when 93.9% by test.The Algorithm is better than the simple robust controller.
2013, 32(10): 1524-1527.
Abstract:
In order to study the effect of dynamic electromagnetic relationship on support characteristic of electromagnetic support device with random variable stiffness,the model for support characteristic was established.With the help of the analogical reasoning method,the effect of dynamic additional support stiffness and damping parameters of the electromagnetic support stiffness was analyzed,as well as reasonable matching relations between random current and bias current and reasonable range of the frequency of random current were obtained.The numerical simulation results showed that the effect of additional support stiffness and damping parameters on the electromagnetic support stiffness could be ignored completely as long as the operating parameters of electromagnetic support device are reasonable,which meets the requirement of random variation characteristic of the support stiffness parameters.
In order to study the effect of dynamic electromagnetic relationship on support characteristic of electromagnetic support device with random variable stiffness,the model for support characteristic was established.With the help of the analogical reasoning method,the effect of dynamic additional support stiffness and damping parameters of the electromagnetic support stiffness was analyzed,as well as reasonable matching relations between random current and bias current and reasonable range of the frequency of random current were obtained.The numerical simulation results showed that the effect of additional support stiffness and damping parameters on the electromagnetic support stiffness could be ignored completely as long as the operating parameters of electromagnetic support device are reasonable,which meets the requirement of random variation characteristic of the support stiffness parameters.
2013, 32(10): 1528-1531.
Abstract:
The brake pedal movement signal is the only signal for a driver to express his brake demand in a braking system that combines regenerative braking and hydraulic braking.It is prone to bring fluctuations between mechanical brake and electric brake,resulting in a poor brake pedal feel.This paper studies the traditional purely hydraulic braking pedal and uses the trajectory tracking control strategy to establish the brake pedal control model of the combined regenerative braking system.The simulation results show that the brake pedal control model can achieve the predetermined automobile brake pedal feel; the brake demand and pedal feel demand can be obtained by solvingthe brake pedal state motion.
The brake pedal movement signal is the only signal for a driver to express his brake demand in a braking system that combines regenerative braking and hydraulic braking.It is prone to bring fluctuations between mechanical brake and electric brake,resulting in a poor brake pedal feel.This paper studies the traditional purely hydraulic braking pedal and uses the trajectory tracking control strategy to establish the brake pedal control model of the combined regenerative braking system.The simulation results show that the brake pedal control model can achieve the predetermined automobile brake pedal feel; the brake demand and pedal feel demand can be obtained by solvingthe brake pedal state motion.
2013, 32(10): 1532-1536.
Abstract:
Piezoelectric materials are widely applied to smart structures and active vibration control fields due to their good electromechanical performance.We select piezoelectric materials as sensor and actuator and take the panel of an airplane as the control object.We also use the Patran to build its finite element model and calculate its data with Nastran,thus obtaining the maximum stress position of the panel in every-order mode.According to the analysis results,we place the possible position and number of piezoelectric patches on the panel.We use the filterX LMS(least means squares) adaptive algorithm to perform the active vibration control of the panel in its singleorder mode and multi-order modes,achieving good control effects,namely first-order mode and second-order mode decreases by 10 dB,5 dB respectively.
Piezoelectric materials are widely applied to smart structures and active vibration control fields due to their good electromechanical performance.We select piezoelectric materials as sensor and actuator and take the panel of an airplane as the control object.We also use the Patran to build its finite element model and calculate its data with Nastran,thus obtaining the maximum stress position of the panel in every-order mode.According to the analysis results,we place the possible position and number of piezoelectric patches on the panel.We use the filterX LMS(least means squares) adaptive algorithm to perform the active vibration control of the panel in its singleorder mode and multi-order modes,achieving good control effects,namely first-order mode and second-order mode decreases by 10 dB,5 dB respectively.
2013, 32(10): 1537-1541.
Abstract:
The flow prediction model based on BP(Back Propagation) neural network was put forward to solute the problem that a complex non-linear relationship exists between solid-phase flow and influencing factors in grain pneumatic conveying pipes,which is difficult to control output production accurately.The model can effectively predict solid-phase flow of system according to the change of pressure loss along pipeline and conveying wind speed,and was simulated by MATLAB software,moreover,was compared with the experimental data.The results show the prediction scheme is convenient,feasible and accurate,which have important instruction significance for detection and control in pneumatic transport system.
The flow prediction model based on BP(Back Propagation) neural network was put forward to solute the problem that a complex non-linear relationship exists between solid-phase flow and influencing factors in grain pneumatic conveying pipes,which is difficult to control output production accurately.The model can effectively predict solid-phase flow of system according to the change of pressure loss along pipeline and conveying wind speed,and was simulated by MATLAB software,moreover,was compared with the experimental data.The results show the prediction scheme is convenient,feasible and accurate,which have important instruction significance for detection and control in pneumatic transport system.
2013, 32(10): 1542-1545.
Abstract:
To make the movements of high wire baler-header meet the operating requirements,the mechanical model and hydraulic system model of baler-header were built with Adams and AMESim in this paper,an electromechanical liquid integration model was integrated with two subsystem models according to the associated parameters in AMESim,and the co-simulation of the mechanical system,hydraulic system and control system was achieved.The co-simulation results showed that the movement of baler-header at different stages is consistent with the setting one,and the correctness of the mechanical model,hydraulic circuit and parameters were also verified.The present study provid a valid theoretic basis for the parameter design and manufacturing of baler-header prototype.
To make the movements of high wire baler-header meet the operating requirements,the mechanical model and hydraulic system model of baler-header were built with Adams and AMESim in this paper,an electromechanical liquid integration model was integrated with two subsystem models according to the associated parameters in AMESim,and the co-simulation of the mechanical system,hydraulic system and control system was achieved.The co-simulation results showed that the movement of baler-header at different stages is consistent with the setting one,and the correctness of the mechanical model,hydraulic circuit and parameters were also verified.The present study provid a valid theoretic basis for the parameter design and manufacturing of baler-header prototype.
2013, 32(10): 1546-1550.
Abstract:
SiC has a ductile micromachining manner under condition with high pressure.In this paper,a series of finite element simulation conducted to comprehend the brittle to ductile transitions micromachining of SiC using the commercial Advantedge version5.6 software.The simulations were run at various rake angle,cutting speed,feed,and initial temperatures throughout the thermal softening regime.The changes in the chip formation,maximum cutting forces and pressures at the tool chip interface were studied.In order to verify the accuracy of simulation results,some contrast simulation results with experimental results from the literature were described.The results showed that ductile machining of brittle materials is more efficient under the condition that the rake angle-45�the smaller cutting edge radius is,the higher cutting speed is,and the smaller depth of cut is.
SiC has a ductile micromachining manner under condition with high pressure.In this paper,a series of finite element simulation conducted to comprehend the brittle to ductile transitions micromachining of SiC using the commercial Advantedge version5.6 software.The simulations were run at various rake angle,cutting speed,feed,and initial temperatures throughout the thermal softening regime.The changes in the chip formation,maximum cutting forces and pressures at the tool chip interface were studied.In order to verify the accuracy of simulation results,some contrast simulation results with experimental results from the literature were described.The results showed that ductile machining of brittle materials is more efficient under the condition that the rake angle-45�the smaller cutting edge radius is,the higher cutting speed is,and the smaller depth of cut is.
2013, 32(10): 1551-1560.
Abstract:
The method for measuring the thermal power of a chip during high-speed nickel alloy milling based on calorimetric method was introduced in this paper.The temperature variation of water with the surroundings during the closed high-speed nickel alloy milling was measured,and the cutting heat in the chip was calculated and compensated for.The power generated by the main cutting force was calculated by measuring the cutting force.The ratio of power in the chip that was generated by the cutting force was calculated too.The experimental study shows that the ratio of power in the chip that was generated by the cutting force increases gradually with the increase of the cutting speed and that the cutting heat carried away by the chip increases too.The cutting heat distribution in the nickel alloy cutting was compared with that in carbon steel cutting; the comparison results showed that the ratio of power in the nickel alloy chip was much smaller.Accordingly,the heat proportion of the incoming tool,which generated higher cutting temperature and caused more serious tool wear in nickel alloy cutting,was relatively higher.
The method for measuring the thermal power of a chip during high-speed nickel alloy milling based on calorimetric method was introduced in this paper.The temperature variation of water with the surroundings during the closed high-speed nickel alloy milling was measured,and the cutting heat in the chip was calculated and compensated for.The power generated by the main cutting force was calculated by measuring the cutting force.The ratio of power in the chip that was generated by the cutting force was calculated too.The experimental study shows that the ratio of power in the chip that was generated by the cutting force increases gradually with the increase of the cutting speed and that the cutting heat carried away by the chip increases too.The cutting heat distribution in the nickel alloy cutting was compared with that in carbon steel cutting; the comparison results showed that the ratio of power in the nickel alloy chip was much smaller.Accordingly,the heat proportion of the incoming tool,which generated higher cutting temperature and caused more serious tool wear in nickel alloy cutting,was relatively higher.
2013, 32(10): 1556-1560.
Abstract:
In order to overcome the disadvantages of the apparent defect inspection technology for quartz wafers,a new method based on the computer vision was proposed in this paper.By analyzing the appearance of the apparent defects of quartz wafers in manufacturing,the defect inspection process was built.Then,a template location algorithm based on the geometrical characteristics and a defect analysis algorithm based on the Blob algorithm were established in order to achieve the different functions of image processing,including acquisition,edge detection,localization,recognition,blob analysis,and so forth.Finally,the system was developed by C#.Net based on the computer vision and the experimental platform was set up.The system achieved capturing the appearance image by using camera and utilized visual sense software to acquire appearance quality of quartz wafers.Furthermore,the system was tested by experiments.The results indicate that the method of apparent defect inspection for quartz wafers has many advantages,including the fast detection speed,the high accuracy which is up to 99.7%,the matching error which is less than 0.3,and the feature which can satisfy the engineering requirements.
In order to overcome the disadvantages of the apparent defect inspection technology for quartz wafers,a new method based on the computer vision was proposed in this paper.By analyzing the appearance of the apparent defects of quartz wafers in manufacturing,the defect inspection process was built.Then,a template location algorithm based on the geometrical characteristics and a defect analysis algorithm based on the Blob algorithm were established in order to achieve the different functions of image processing,including acquisition,edge detection,localization,recognition,blob analysis,and so forth.Finally,the system was developed by C#.Net based on the computer vision and the experimental platform was set up.The system achieved capturing the appearance image by using camera and utilized visual sense software to acquire appearance quality of quartz wafers.Furthermore,the system was tested by experiments.The results indicate that the method of apparent defect inspection for quartz wafers has many advantages,including the fast detection speed,the high accuracy which is up to 99.7%,the matching error which is less than 0.3,and the feature which can satisfy the engineering requirements.
