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RSS2014 Vol. 33, No. 8
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2014, 33(8): 1136-1140.
doi: 10.13433/j.cnki.1003-8728.2014.0805
PDF 607KB
Abstract:
For the fatigue life prediction of helical gear pair in air compressor,a rapid fatigue life prediction method based on CAE collaborative simulation technology is presented in this paper. The three-dimensional nonlinear finite element model of the high contact ratio helical gears is established using ANSYS software to calculate the stress distribution,then meshing impact is reduced by profile modification. Combined with the actual approximate load spectrum obtained by using ADAMS software,fatigue life predictions is carried out using FE-SAFE software based on the theory of fatigue damage. The results show that tooth profile modification can effectively reduce large shocks caused by elastic deformation during meshing,load spectrum can be quickly obtained by uisng ADAMS software the fatigue life of helical gear pair after modification can meet the design requirements and be consistent with the actual situation.
For the fatigue life prediction of helical gear pair in air compressor,a rapid fatigue life prediction method based on CAE collaborative simulation technology is presented in this paper. The three-dimensional nonlinear finite element model of the high contact ratio helical gears is established using ANSYS software to calculate the stress distribution,then meshing impact is reduced by profile modification. Combined with the actual approximate load spectrum obtained by using ADAMS software,fatigue life predictions is carried out using FE-SAFE software based on the theory of fatigue damage. The results show that tooth profile modification can effectively reduce large shocks caused by elastic deformation during meshing,load spectrum can be quickly obtained by uisng ADAMS software the fatigue life of helical gear pair after modification can meet the design requirements and be consistent with the actual situation.
2014, 33(8): 1141-1144.
doi: 10.13433/j.cnki.1003-8728.2014.0806
Abstract:
To support complex product design efficiently,a multi-level assembly model design method is put forward based on Top-Down design and 3D layout. The multi-level assembly model has two levels: layout model level and detail model level. In the layout model level,datum geometry is used to represent the relative space position of parts,while convex hull is used to represent spatial shape. The result of layout model level is a 3D layout skeleton model,designers can get the final detail model based on the 3D layout model. Finally,a high-speed train bogie is designed to verify the feasibility of the proposed method based on the CATIA platform.
To support complex product design efficiently,a multi-level assembly model design method is put forward based on Top-Down design and 3D layout. The multi-level assembly model has two levels: layout model level and detail model level. In the layout model level,datum geometry is used to represent the relative space position of parts,while convex hull is used to represent spatial shape. The result of layout model level is a 3D layout skeleton model,designers can get the final detail model based on the 3D layout model. Finally,a high-speed train bogie is designed to verify the feasibility of the proposed method based on the CATIA platform.
2014, 33(8): 1145-1149.
doi: 10.13433/j.cnki.1003-8728.2014.0807
Abstract:
In order to accurately understand the ink transfer characteristic of the inking system,based on elastohydrodynamically lubricated theory of inking system,the equation of the minimum film thickness between rollers in inking system is established,and the minimum film thickness is obtained by solving the equation under given parameter. The simulation results of inking system indicate that the rollers' sizes,contact pressure and entrainment speed have an impact on the minimum film thickness. The results also show that: with the increasing of contact pressure of ink roller of inking system,the minimum film thickness will be decreased; the rotating rate of ink roller of inking system has a great impact on the ink thickness and the time to reach steady state; with the increasing of the printing speed,the layer thickness of the substrate surface increases quickly,and the time to reach steady state becomes long.
In order to accurately understand the ink transfer characteristic of the inking system,based on elastohydrodynamically lubricated theory of inking system,the equation of the minimum film thickness between rollers in inking system is established,and the minimum film thickness is obtained by solving the equation under given parameter. The simulation results of inking system indicate that the rollers' sizes,contact pressure and entrainment speed have an impact on the minimum film thickness. The results also show that: with the increasing of contact pressure of ink roller of inking system,the minimum film thickness will be decreased; the rotating rate of ink roller of inking system has a great impact on the ink thickness and the time to reach steady state; with the increasing of the printing speed,the layer thickness of the substrate surface increases quickly,and the time to reach steady state becomes long.
2014, 33(8): 1150-1154.
doi: 10.13433/j.cnki.1003-8728.2014.0808
Abstract:
The design of the planetary gear train is a complicated work,in which each parameter restricted by the conditions such as teeth,reliability and interference can not be chosen arbitrarily; and the modulus constrained by national standards must be only selected as a number of discrete values,so the classic optimization algorithm is poor to solve this work well. The processing object of genetic algorithm is encoded genes rather than the variable itself,and this innate advantage can deal with such optimization problem with diverse types of variables better. Unordered discrete values are changed into consecutive integers through processing the number of teeth and the modulus. An improved encoding way of real value is proposed and the optimization models for planetary gear train with volume smallest objective function is constructed,which can satisfy the conditions such as teeth,modification coefficient,interference and strength. The models are solved by means of Matlab programming language through reasonably choosing the control parameters of genetic algorithm. The results show that the improved algorithm has better global optimization capability and converges to an optimal point in several startups. The optimized volume has decreased21. 056% under the constraints above. This optimization design method has a certain value of economic and engineering applications.
The design of the planetary gear train is a complicated work,in which each parameter restricted by the conditions such as teeth,reliability and interference can not be chosen arbitrarily; and the modulus constrained by national standards must be only selected as a number of discrete values,so the classic optimization algorithm is poor to solve this work well. The processing object of genetic algorithm is encoded genes rather than the variable itself,and this innate advantage can deal with such optimization problem with diverse types of variables better. Unordered discrete values are changed into consecutive integers through processing the number of teeth and the modulus. An improved encoding way of real value is proposed and the optimization models for planetary gear train with volume smallest objective function is constructed,which can satisfy the conditions such as teeth,modification coefficient,interference and strength. The models are solved by means of Matlab programming language through reasonably choosing the control parameters of genetic algorithm. The results show that the improved algorithm has better global optimization capability and converges to an optimal point in several startups. The optimized volume has decreased21. 056% under the constraints above. This optimization design method has a certain value of economic and engineering applications.
2014, 33(8): 1155-1160.
doi: 10.13433/j.cnki.1003-8728.2014.0809
Abstract:
In ultrasonic spinning system,to achieve ultrasound spinning smoothly,the output amplitude through the ultrasonic transformer transducer must be enlarged,and the ideal resonance frequency and vibration model must be carefully designed to get the right processing amplitude,thus the amplitude transformer design in ultrasonic spinning system is very important. This study conducted structural design calculation of ultrasonic compound amplitude transformer(or compound horn),and conducted modal analysis with the use of Marc finite element analysis software,obtained the resonant frequencies under the designed modes,demonstrated the accuracy of theoretical design calculation. Simulation and vibration trial results proved that the designed compound horn can satisfy the requirements of general ultrasound spinning.
In ultrasonic spinning system,to achieve ultrasound spinning smoothly,the output amplitude through the ultrasonic transformer transducer must be enlarged,and the ideal resonance frequency and vibration model must be carefully designed to get the right processing amplitude,thus the amplitude transformer design in ultrasonic spinning system is very important. This study conducted structural design calculation of ultrasonic compound amplitude transformer(or compound horn),and conducted modal analysis with the use of Marc finite element analysis software,obtained the resonant frequencies under the designed modes,demonstrated the accuracy of theoretical design calculation. Simulation and vibration trial results proved that the designed compound horn can satisfy the requirements of general ultrasound spinning.
2014, 33(8): 1161-1166.
doi: 10.13433/j.cnki.1003-8728.2014.0810
Abstract:
SiC Monocrystal is widely used in high power devices and IC industry due to its good physical and mechanical properties. However,the processing process of SiC monosrystal wafers becomes very difficult due to its high hardness and brittleness. The cutting force has an important influence on the quality,productivity and stability of cutting process in SiC monocrystal wafer processing; therefore,it is significant to study the cutting force of the cutting process. This paper analyzes the influence factors on cutting force of the cutting process,the experiment scheme is designed by using Central Composite Design(CCD),and the wire saw velocity,part feed rate,part rotation speed and wire saw tension are considered as the factors on the cutting force of SiC processing. Response Surface Methodology(RSM) is used to optimize the processing parameters and the cutting force model is developed. Analysis of variance(ANOVA) is also carried out to verify the feasibility of the cutting force model. The experiments results show that the proposed model can predict the cutting force effectively in SiC monocrystal wafers cutting process.
SiC Monocrystal is widely used in high power devices and IC industry due to its good physical and mechanical properties. However,the processing process of SiC monosrystal wafers becomes very difficult due to its high hardness and brittleness. The cutting force has an important influence on the quality,productivity and stability of cutting process in SiC monocrystal wafer processing; therefore,it is significant to study the cutting force of the cutting process. This paper analyzes the influence factors on cutting force of the cutting process,the experiment scheme is designed by using Central Composite Design(CCD),and the wire saw velocity,part feed rate,part rotation speed and wire saw tension are considered as the factors on the cutting force of SiC processing. Response Surface Methodology(RSM) is used to optimize the processing parameters and the cutting force model is developed. Analysis of variance(ANOVA) is also carried out to verify the feasibility of the cutting force model. The experiments results show that the proposed model can predict the cutting force effectively in SiC monocrystal wafers cutting process.
2014, 33(8): 1167-1171.
doi: 10.13433/j.cnki.1003-8728.2014.0811
Abstract:
The relationship between the electric parameter and the processing quality is analyzed,and the optimum electric parameter is predicted by using the support vector machine(SVM). The simulation result shows that the highest prediction accuracy is 96. 1%,the lowest is 89. 2%,the average accuracy is 94. 28%,which indicate the algorithm stability and generalization ability are outstanding,after the experiment,the highest prediction accuracy can reach to 92. 65%,the lowest is 81. 5%,the average accuracy is 89. 38%,the electric parameter optimized based on the SVM can guarantee the expected processing effect better. The exploration in EDM intelligent machining will be convenient for the operators to determine the most effective machining condition.
The relationship between the electric parameter and the processing quality is analyzed,and the optimum electric parameter is predicted by using the support vector machine(SVM). The simulation result shows that the highest prediction accuracy is 96. 1%,the lowest is 89. 2%,the average accuracy is 94. 28%,which indicate the algorithm stability and generalization ability are outstanding,after the experiment,the highest prediction accuracy can reach to 92. 65%,the lowest is 81. 5%,the average accuracy is 89. 38%,the electric parameter optimized based on the SVM can guarantee the expected processing effect better. The exploration in EDM intelligent machining will be convenient for the operators to determine the most effective machining condition.
2014, 33(8): 1172-1176.
doi: 10.13433/j.cnki.1003-8728.2014.0812
Abstract:
Aiming at the issues of parts requirement in the process of variant design for complicated product,a part traversal was proposed. Product main model was established according to the mating relationship among constituent parts of product. Then,product main model and the characteristics of traversal algorithm were analyzed,parts traversal rules adaptive for complicated product variant design was given,parts traverse direction for product were provided. The 3D(Three Dimensions) of Solidworks was developed with VC++(Visual C++). The complicated product's variant design was implemented. Finally,an example of garbage crusher is given to verify all methods which were applied.
Aiming at the issues of parts requirement in the process of variant design for complicated product,a part traversal was proposed. Product main model was established according to the mating relationship among constituent parts of product. Then,product main model and the characteristics of traversal algorithm were analyzed,parts traversal rules adaptive for complicated product variant design was given,parts traverse direction for product were provided. The 3D(Three Dimensions) of Solidworks was developed with VC++(Visual C++). The complicated product's variant design was implemented. Finally,an example of garbage crusher is given to verify all methods which were applied.
2014, 33(8): 1177-1182.
doi: 10.13433/j.cnki.1003-8728.2014.0813
Abstract:
In allusion to deficiencies of the existing methods of curve offset on surface,an offset method of geodesic B-spline curves on manifold triangulation surface is proposed in this study. In this method,the offset problem of curves on manifold triangulation is converted to simpler problem that offset of curves on plane. As for a given geodesic B-spine curve on manifold triangulation surface,firstly,the region where geodesic B-spline curve is parameterized locally using discrete exponential maps; secondly,the curve in the parameter domain is offset using the method based on shifting control points; finally,the offset curve is mapped to the manifold triangulation surface using parameter matching,and finishing the work that offset of curve on surface. According to the self-intersections that appeared in the offset curve on plane,a new approach that detecting and eliminating self-intersections is proposed,which can eliminate self-intersection effectively. The results show that the proposed method is not only robust,effective,and able to meet the interactive design requirements,but also the expression of offset curve consistent with the source curve.
In allusion to deficiencies of the existing methods of curve offset on surface,an offset method of geodesic B-spline curves on manifold triangulation surface is proposed in this study. In this method,the offset problem of curves on manifold triangulation is converted to simpler problem that offset of curves on plane. As for a given geodesic B-spine curve on manifold triangulation surface,firstly,the region where geodesic B-spline curve is parameterized locally using discrete exponential maps; secondly,the curve in the parameter domain is offset using the method based on shifting control points; finally,the offset curve is mapped to the manifold triangulation surface using parameter matching,and finishing the work that offset of curve on surface. According to the self-intersections that appeared in the offset curve on plane,a new approach that detecting and eliminating self-intersections is proposed,which can eliminate self-intersection effectively. The results show that the proposed method is not only robust,effective,and able to meet the interactive design requirements,but also the expression of offset curve consistent with the source curve.
2014, 33(8): 1183-1185.
doi: 10.13433/j.cnki.1003-8728.2014.0814
Abstract:
The FEM model for cutting titanium alloy is established. The effect of the tool wear on the chip morphology,cutting temperature and cutting force are studied based on the present FEM model. The production mechanism of these effects is also discussed. The simulation results show that the cutting force and cutting temperature will rise with the increasing of tool wear. The oscillation of cutting force is caused mainly by tool crater wear and oscillation amplitude raise with the increasing of crater wear,meanwhile,the rise of cutting force is caused mainly by flank wear. Furthermore,the degree of chip deformation increases in the cutting process of Ti6Al4 V titanium alloy by using saw tooth,but the occurred frequency of saw tooth decreases.
The FEM model for cutting titanium alloy is established. The effect of the tool wear on the chip morphology,cutting temperature and cutting force are studied based on the present FEM model. The production mechanism of these effects is also discussed. The simulation results show that the cutting force and cutting temperature will rise with the increasing of tool wear. The oscillation of cutting force is caused mainly by tool crater wear and oscillation amplitude raise with the increasing of crater wear,meanwhile,the rise of cutting force is caused mainly by flank wear. Furthermore,the degree of chip deformation increases in the cutting process of Ti6Al4 V titanium alloy by using saw tooth,but the occurred frequency of saw tooth decreases.
2014, 33(8): 1186-1191.
doi: 10.13433/j.cnki.1003-8728.2014.0815
Abstract:
A quasi-static analytical model for needle bearings was established and the bearing load distribution was calculated based on the model by computer program. The four key influencing factors on the bearing load distribution were determined as the loading,misalignment,clearance and crown. The uniform of load distribution is used as the evaluating indicator of bearing load distribution uniformity. Mathematical model was set up and the effect of various factors on load distribution of degree was analyzed by using quadratic regression orthogonal method.The model of optimized calculation was established based on the mathematical model,and the optimal crown and maximum angle of bearing were determined by using calculation.
A quasi-static analytical model for needle bearings was established and the bearing load distribution was calculated based on the model by computer program. The four key influencing factors on the bearing load distribution were determined as the loading,misalignment,clearance and crown. The uniform of load distribution is used as the evaluating indicator of bearing load distribution uniformity. Mathematical model was set up and the effect of various factors on load distribution of degree was analyzed by using quadratic regression orthogonal method.The model of optimized calculation was established based on the mathematical model,and the optimal crown and maximum angle of bearing were determined by using calculation.
2014, 33(8): 1192-1196.
doi: 10.13433/j.cnki.1003-8728.2014.0816
Abstract:
Both the finite element method and the dynamics method are conducted to investigate the engaging characteristics of new developed high power and high speed spring clutch in different friction condition. The threedimensional finite element analysis model for spring clutch,which consists of spring,input and output housing,is established via Abaqus platform. Through analysis,response and engaging time of clutch inside and outside ring and Mises stress and radial displacement of spring are obtained. The results illustrate the response of the clutch is quick,the steady state Mises stress of the spring is well-distributed and the radial displacement of the spring is not completely contacted with housing. The loading of the clutch still has some allowance. The engaging and response time of the clutch is not influenced too much by the friction coefficient. The friction coefficient influences the Mises stress of the spring and radial displacement of the spring.
Both the finite element method and the dynamics method are conducted to investigate the engaging characteristics of new developed high power and high speed spring clutch in different friction condition. The threedimensional finite element analysis model for spring clutch,which consists of spring,input and output housing,is established via Abaqus platform. Through analysis,response and engaging time of clutch inside and outside ring and Mises stress and radial displacement of spring are obtained. The results illustrate the response of the clutch is quick,the steady state Mises stress of the spring is well-distributed and the radial displacement of the spring is not completely contacted with housing. The loading of the clutch still has some allowance. The engaging and response time of the clutch is not influenced too much by the friction coefficient. The friction coefficient influences the Mises stress of the spring and radial displacement of the spring.
2014, 33(8): 1197-1202.
doi: 10.13433/j.cnki.1003-8728.2014.0817
Abstract:
The rotary kiln is a super large cylinder equipment which can apply mechanical,physical or chemical treatment to solid materials,which is widely used in building materials,metallurgy,chemical and the other industries. The rotary kiln works in the complex conditions. In the working conditions,the rotary kiln shell axis offsets the theory axis which leads to the problems such as unevenly stress,wearing aggravation,and life shortening and so on of some components. First,the rotary kiln model was simulated and calculated though finite element analysis. Then,to satisfy the aim that each component force being balance and the cylinder axis being straight simultaneously,taking the spacing between the various stalls,initial value,adjustment of rotary kiln and support angle as design variables,the rotary kiln is optimized based on the objective of equal load and same coaxial line. At last,on the basis of the data of calculated results,a quadratic polynomial response surface model was created,and the influence degree to the result of design variables was obtained. After the calculation,the mathematical expressions of vertical and horizontal stress response surface models for roller were obtained.
The rotary kiln is a super large cylinder equipment which can apply mechanical,physical or chemical treatment to solid materials,which is widely used in building materials,metallurgy,chemical and the other industries. The rotary kiln works in the complex conditions. In the working conditions,the rotary kiln shell axis offsets the theory axis which leads to the problems such as unevenly stress,wearing aggravation,and life shortening and so on of some components. First,the rotary kiln model was simulated and calculated though finite element analysis. Then,to satisfy the aim that each component force being balance and the cylinder axis being straight simultaneously,taking the spacing between the various stalls,initial value,adjustment of rotary kiln and support angle as design variables,the rotary kiln is optimized based on the objective of equal load and same coaxial line. At last,on the basis of the data of calculated results,a quadratic polynomial response surface model was created,and the influence degree to the result of design variables was obtained. After the calculation,the mathematical expressions of vertical and horizontal stress response surface models for roller were obtained.
2014, 33(8): 1203-1206.
doi: 10.13433/j.cnki.1003-8728.2014.0818
Abstract:
In the study of crane hoisting system rolling control,the design of displacement and pendulum for car slot system controller can respectively be carried out. Because the crane pendulum slot system hoisting pendulum cape speed general by sensor measurement,the operation and maintenance costs increased. The status information of nonlinear extended state observer for crane pendulum slot system was reconstructed,soft measurement pendulum cape speed was put forward. The observer structural equation was given,and the observer parameters were optimized by using Matlab. After the parameters setting of the extended state observer can be in 0. 3 s. inside estimate system pendulum Angle and pendulum angular velocity,and in 0. 5 s. estimate within the system interference. The simulation results show that can realize the nonlinear crane pendulum slot system status information of the soft measurement after Matlab parameter setting of the extended state observer(extend state observer,ESO).
In the study of crane hoisting system rolling control,the design of displacement and pendulum for car slot system controller can respectively be carried out. Because the crane pendulum slot system hoisting pendulum cape speed general by sensor measurement,the operation and maintenance costs increased. The status information of nonlinear extended state observer for crane pendulum slot system was reconstructed,soft measurement pendulum cape speed was put forward. The observer structural equation was given,and the observer parameters were optimized by using Matlab. After the parameters setting of the extended state observer can be in 0. 3 s. inside estimate system pendulum Angle and pendulum angular velocity,and in 0. 5 s. estimate within the system interference. The simulation results show that can realize the nonlinear crane pendulum slot system status information of the soft measurement after Matlab parameter setting of the extended state observer(extend state observer,ESO).
2014, 33(8): 1207-1209.
doi: 10.13433/j.cnki.1003-8728.2014.0819
Abstract:
To obtain a macromodel is a key to design and simulate the micromixer. The Navier-Stokes equation and the convection-diffusion equation with finite element method were discretized,and a system of algebraic differential equations was gotten. The macromodel was obtained from the system of algebraic differential equations by Arnoldi process based on the Krylov subspace technique. The simulation result demonstrated the reduced-order macromodel maintains the output accuracy of micromixer and reduces computational complexity.
To obtain a macromodel is a key to design and simulate the micromixer. The Navier-Stokes equation and the convection-diffusion equation with finite element method were discretized,and a system of algebraic differential equations was gotten. The macromodel was obtained from the system of algebraic differential equations by Arnoldi process based on the Krylov subspace technique. The simulation result demonstrated the reduced-order macromodel maintains the output accuracy of micromixer and reduces computational complexity.
2014, 33(8): 1210-1213.
doi: 10.13433/j.cnki.1003-8728.2014.0820
Abstract:
Main reducer of automobile is the key element in the driving axles,and its noise level is an important index to evaluate the power property of the whole driving system. In order to meet the on-line noise measurement of main reducer,the vibration velocity method is applied to detect its noise on line. Also,it is studied that how the noise of main reducer is affected by its rotating speed,load and no-loaded dragging moment. The testing results show that rotating speed is the key factor to affect the noise of automobile main reducer,and the load and no-loaded dragging moment have less impact to its noise. The noise frequency chart of main reducer is great different between load and no-loaded conditions. Gained results provide the useful rules for the main reducer manufacturer to analyze the more important factor of its noise and to design its on-line testing criterion for the NVH properties.
Main reducer of automobile is the key element in the driving axles,and its noise level is an important index to evaluate the power property of the whole driving system. In order to meet the on-line noise measurement of main reducer,the vibration velocity method is applied to detect its noise on line. Also,it is studied that how the noise of main reducer is affected by its rotating speed,load and no-loaded dragging moment. The testing results show that rotating speed is the key factor to affect the noise of automobile main reducer,and the load and no-loaded dragging moment have less impact to its noise. The noise frequency chart of main reducer is great different between load and no-loaded conditions. Gained results provide the useful rules for the main reducer manufacturer to analyze the more important factor of its noise and to design its on-line testing criterion for the NVH properties.
2014, 33(8): 1214-1218.
doi: 10.13433/j.cnki.1003-8728.2014.0821
Abstract:
Yaw rate is an important indicator to characterize vehicle lateral stability,so it becomes a key control variable in the vehicle handling and stability control system. On the other hand,PID is one of the most common control methods since it is easy to be implemented,but its engineering application is limited for parameter tuning.Based on the response surface theory,taking the amplitude of front wheel steering angle and the parameters of PID controller as the inputs of response surface,and taking the key points of the vehicle yaw rate curve as the outputs of response surface,an 8 degrees of freedom vehicle dynamics surrogate model is built in this paper integrated with PID controller. This method can not only avoid considering the time state factors of surrogate model,but also can optimize PID controller parameters quickly. Numerical simulations demonstrate that the surrogate model based on the presented method has high precision,and the vehicle yaw rate can track the desired yaw rate accurately recurred to the PID controller,by which the vehicle lateral stability is improved effectively.
Yaw rate is an important indicator to characterize vehicle lateral stability,so it becomes a key control variable in the vehicle handling and stability control system. On the other hand,PID is one of the most common control methods since it is easy to be implemented,but its engineering application is limited for parameter tuning.Based on the response surface theory,taking the amplitude of front wheel steering angle and the parameters of PID controller as the inputs of response surface,and taking the key points of the vehicle yaw rate curve as the outputs of response surface,an 8 degrees of freedom vehicle dynamics surrogate model is built in this paper integrated with PID controller. This method can not only avoid considering the time state factors of surrogate model,but also can optimize PID controller parameters quickly. Numerical simulations demonstrate that the surrogate model based on the presented method has high precision,and the vehicle yaw rate can track the desired yaw rate accurately recurred to the PID controller,by which the vehicle lateral stability is improved effectively.
2014, 33(8): 1219-1224.
doi: 10.13433/j.cnki.1003-8728.2014.0822
Abstract:
In order to testify the effect of articulated body layout scheme on the articulated vehicle frame,the virtual prototype model for articulated vehicle was established by using ADAMS software. The effect of two different articulated body layout form-front-articulated body and rear-articulated body-on the full vehicle pivot steering performances was studied. The results showed that the front-articulated body scheme dropped the phenomenon of body roll in the progress of pivot steering,reduced wheel load transfer between inner side and outside tires by above50%,and the force on articulated body at the full vehicle directions of longitudinal and lateral was also improved,the motion trail of the two schemes was almost identical.
In order to testify the effect of articulated body layout scheme on the articulated vehicle frame,the virtual prototype model for articulated vehicle was established by using ADAMS software. The effect of two different articulated body layout form-front-articulated body and rear-articulated body-on the full vehicle pivot steering performances was studied. The results showed that the front-articulated body scheme dropped the phenomenon of body roll in the progress of pivot steering,reduced wheel load transfer between inner side and outside tires by above50%,and the force on articulated body at the full vehicle directions of longitudinal and lateral was also improved,the motion trail of the two schemes was almost identical.
2014, 33(8): 1225-1232.
doi: 10.13433/j.cnki.1003-8728.2014.0823
Abstract:
To analyze the force of steering system of vehicle is completed,and the steering wheel resistant torque models of different working conditions are established. a parameterized ideal steering wheel torque model of driver is put forward and the design mechanism of assisted characteristic curve of EPS is studied based on the present model,then which present that the assisted characteristic curve should be designed separately according to the vehicle speed and the design procedure should be based on the relation between ideal steering wheel torque model of driver and vehicle speed,steering wheel angle and lateral acceleration,then the process of assisted characteristic curve of EPS is formed,simultaneously which give a proof of the geometric character of assisted characteristic curve of EPS in detail.
To analyze the force of steering system of vehicle is completed,and the steering wheel resistant torque models of different working conditions are established. a parameterized ideal steering wheel torque model of driver is put forward and the design mechanism of assisted characteristic curve of EPS is studied based on the present model,then which present that the assisted characteristic curve should be designed separately according to the vehicle speed and the design procedure should be based on the relation between ideal steering wheel torque model of driver and vehicle speed,steering wheel angle and lateral acceleration,then the process of assisted characteristic curve of EPS is formed,simultaneously which give a proof of the geometric character of assisted characteristic curve of EPS in detail.
2014, 33(8): 1233-1237.
doi: 10.13433/j.cnki.1003-8728.2014.0824
Abstract:
Aiming at the problems that traditional electric power steering(EPS) system cannot implement active steering when vehicles running in limiting condition and also can' t actively compensate on the driver' s steering misuse,the full vehicle handling dynamic model of EPS integrated with the function of active steering is established in this paper. Then taking the steering portability,sensitivity,return ability and handling stability as the system evaluation outputs,the control characteristics of EPS based on full vehicle handling stability is simulated using the strategy of H∞ robust control. The simulation results show that the EPS integrated active steering not only can realize the traditional EPS control characteristics,but also can implement the active steering according to the vehicle steering stability requirements in the limiting operation condition. Thus,the vehicle yaw rate and side-slip angle are reduced effectively and the function adjusting range of EPS is played furthest.
Aiming at the problems that traditional electric power steering(EPS) system cannot implement active steering when vehicles running in limiting condition and also can' t actively compensate on the driver' s steering misuse,the full vehicle handling dynamic model of EPS integrated with the function of active steering is established in this paper. Then taking the steering portability,sensitivity,return ability and handling stability as the system evaluation outputs,the control characteristics of EPS based on full vehicle handling stability is simulated using the strategy of H∞ robust control. The simulation results show that the EPS integrated active steering not only can realize the traditional EPS control characteristics,but also can implement the active steering according to the vehicle steering stability requirements in the limiting operation condition. Thus,the vehicle yaw rate and side-slip angle are reduced effectively and the function adjusting range of EPS is played furthest.
2014, 33(8): 1238-1241.
doi: 10.13433/j.cnki.1003-8728.2014.0825
Abstract:
Heavy-duty vehicle bypass flow type electronically controlled hydraulic power steering system(ECHPS)regulates hydraulic assist force by varying the volume of by-pass oil,and thus realizes low-speed steering portability and high-speed stability. Due to the massive by-pass flow,the steering responsiveness descends when steering at high speed. The idea of applying an extra torque is proposed to improve the steering sensitivity when steering urgently. The extra torque control strategy based on speed and steering angle rate was studied. At the same angle rate,the higher the proportion valve controlled voltage is the faster the vehicle speed is,while the assist force is smaller. At the same vehicle speed,with the increasing of angle rate,the voltage of proportional valve is reduced,and the assist force is increased. The extra torque control model is established and simulated,the results verify the validity of control strategy and indicate that the extra torque can enhance ECHPS quick responsiveness at urgent turning.
Heavy-duty vehicle bypass flow type electronically controlled hydraulic power steering system(ECHPS)regulates hydraulic assist force by varying the volume of by-pass oil,and thus realizes low-speed steering portability and high-speed stability. Due to the massive by-pass flow,the steering responsiveness descends when steering at high speed. The idea of applying an extra torque is proposed to improve the steering sensitivity when steering urgently. The extra torque control strategy based on speed and steering angle rate was studied. At the same angle rate,the higher the proportion valve controlled voltage is the faster the vehicle speed is,while the assist force is smaller. At the same vehicle speed,with the increasing of angle rate,the voltage of proportional valve is reduced,and the assist force is increased. The extra torque control model is established and simulated,the results verify the validity of control strategy and indicate that the extra torque can enhance ECHPS quick responsiveness at urgent turning.
2014, 33(8): 1242-1244.
doi: 10.13433/j.cnki.1003-8728.2014.0826
Abstract:
With the noise radiation energy distribution of an automobile engine as the reference,and the soundabsorbing material which is actually used as the test object,the research is carried out in the following steps:firstly,two microphones were placed equidistantly in front of the sound-absorbing material,then the sound pressure values at the locations of the two microphones were measured respectively by using the microphones,and Laplace transform was made for the measured sound pressure; secondly,the reflection coefficient of the sound absorbingmaterial was obtained according to the time delay of sound pressure measured between two microphones; finally,the sound absorption coefficient was derived by using the reflection coefficient of the sound-absorbing material.Experiment results show that the sound absorption coefficient measured by this method is nearly the same as those measured by standing wave tube and reverberation room methods in low frequency range. Taking the automobile engine noise radiation energy distribution as reference,the proposed method to measure sound absorption coefficient based on time delay is fast and reliable.
With the noise radiation energy distribution of an automobile engine as the reference,and the soundabsorbing material which is actually used as the test object,the research is carried out in the following steps:firstly,two microphones were placed equidistantly in front of the sound-absorbing material,then the sound pressure values at the locations of the two microphones were measured respectively by using the microphones,and Laplace transform was made for the measured sound pressure; secondly,the reflection coefficient of the sound absorbingmaterial was obtained according to the time delay of sound pressure measured between two microphones; finally,the sound absorption coefficient was derived by using the reflection coefficient of the sound-absorbing material.Experiment results show that the sound absorption coefficient measured by this method is nearly the same as those measured by standing wave tube and reverberation room methods in low frequency range. Taking the automobile engine noise radiation energy distribution as reference,the proposed method to measure sound absorption coefficient based on time delay is fast and reliable.
2014, 33(8): 1245-1250.
doi: 10.13433/j.cnki.1003-8728.2014.0827
Abstract:
A two-dimensional orthogonal thermo-mechanical coupling a cutting model of Ti-6Al-4V is developed to precisely model the cutting process of titanium alloy. The crack extending energy theory in fracture mechanics is integrated into cutting simulation to act as material damage evolution criteria. The ultimate shear stress in tool and chip interface is considered to change with coefficient of friction,in which the coefficient of friction is also treated to a function of temperature. The finite element model is validated through turning experiment and chip metallographic observation experiment. The results show that simulation cutting force and segmented chip morphology well coincide with the experimental. The machining surface residual stress is analyzed. The effect of rake angle on chip damage degree,morphology,shear angle,tool temperature is predicted based on the validated model.
A two-dimensional orthogonal thermo-mechanical coupling a cutting model of Ti-6Al-4V is developed to precisely model the cutting process of titanium alloy. The crack extending energy theory in fracture mechanics is integrated into cutting simulation to act as material damage evolution criteria. The ultimate shear stress in tool and chip interface is considered to change with coefficient of friction,in which the coefficient of friction is also treated to a function of temperature. The finite element model is validated through turning experiment and chip metallographic observation experiment. The results show that simulation cutting force and segmented chip morphology well coincide with the experimental. The machining surface residual stress is analyzed. The effect of rake angle on chip damage degree,morphology,shear angle,tool temperature is predicted based on the validated model.
2014, 33(8): 1251-1254.
doi: 10.13433/j.cnki.1003-8728.2014.0828
Abstract:
In order to improve the measuring accuracy and efficiency,the crack compliance method was adopted to measure the original residual stresses in the pre-stretched aluminum alloy plates,the accuracy of the measured strain and the computational efficiency of the compliance functions were discussed. The "Load Case"of ABAQUS software was applied to optimize the calculation method of compliance function. Then,the original residual stresses in the pre-stretched aluminum alloy plate 7050-T7451 were measured. The high efficiency,high precision measurement procedures of residual stress and emergency response mechanism were established based on the crack compliance method. The calculated results show the computational efficiency was improved obviously; "M type curves"of residual stresses were obtained for the rolling and the transverse directions.
In order to improve the measuring accuracy and efficiency,the crack compliance method was adopted to measure the original residual stresses in the pre-stretched aluminum alloy plates,the accuracy of the measured strain and the computational efficiency of the compliance functions were discussed. The "Load Case"of ABAQUS software was applied to optimize the calculation method of compliance function. Then,the original residual stresses in the pre-stretched aluminum alloy plate 7050-T7451 were measured. The high efficiency,high precision measurement procedures of residual stress and emergency response mechanism were established based on the crack compliance method. The calculated results show the computational efficiency was improved obviously; "M type curves"of residual stresses were obtained for the rolling and the transverse directions.
2014, 33(8): 1255-1258.
doi: 10.13433/j.cnki.1003-8728.2014.0829
Abstract:
Carbon fiber reinforced plastics is a typical difficult-to-machine material. Milling is the most practical machining operation for machining composite materials. The decrease in milling force can improve the surface quality of the parts and reduce tool wear. The milling force has been studied with carbide mill during the milling of CFRP. The regression analysis is carried out with software Excel. At last,the empirical formulas of milling force are derived. The results show that the feed speed has great effect on the milling force. The milling force increases with the increasing of feed speed. On the other hand,the spindle speed has slight influence on the milling force,and the milling force gradually increases with the increasing of spindle speed.
Carbon fiber reinforced plastics is a typical difficult-to-machine material. Milling is the most practical machining operation for machining composite materials. The decrease in milling force can improve the surface quality of the parts and reduce tool wear. The milling force has been studied with carbide mill during the milling of CFRP. The regression analysis is carried out with software Excel. At last,the empirical formulas of milling force are derived. The results show that the feed speed has great effect on the milling force. The milling force increases with the increasing of feed speed. On the other hand,the spindle speed has slight influence on the milling force,and the milling force gradually increases with the increasing of spindle speed.
2014, 33(8): 1259-1263.
doi: 10.13433/j.cnki.1003-8728.2014.0830
Abstract:
For obtaining larger useful displacement of the giant magnetostrictive actuator, a displacement transmission mechanism is designed to combine the output of giant magnetostrictive rod and canister. The electromagnetic calculation model is established based on the finite element method in allusion to magnetic field distribution and the simulation is done by ANSYS software. The magnetic field strength at any point inside the material is achieved through simulation and the magnetic field strength average of the cross section is calculated by a new averaging way. At last the axial distribution of the magnetic field strength on the rod and canister is protracted with displacement transmission mechanism's varied permeability.
For obtaining larger useful displacement of the giant magnetostrictive actuator, a displacement transmission mechanism is designed to combine the output of giant magnetostrictive rod and canister. The electromagnetic calculation model is established based on the finite element method in allusion to magnetic field distribution and the simulation is done by ANSYS software. The magnetic field strength at any point inside the material is achieved through simulation and the magnetic field strength average of the cross section is calculated by a new averaging way. At last the axial distribution of the magnetic field strength on the rod and canister is protracted with displacement transmission mechanism's varied permeability.
2014, 33(8): 1264-1267.
doi: 10.13433/j.cnki.1003-8728.2014.0831
Abstract:
The ADAMS virtual prototyping software is applied to study the commercial aircraft emergency evacuation slide release process,and the motional coordination design technique of slide pack and aircraft translational open cabin door during slide release is analyzed in this paper. The simulation model of slide release is established with the restraints between slide pack and the fuselage structures which are considered as a contact-impact model. Slide release process is preferably simulated. Parameters that affect the slide release are simulated. The result shows that smoothly slide release can be achieved by lengthening release cable or increasing cabin door opening speed and the relationship between cabin door opening speed and the load on the girt when the slide pack falls outside of the sill is analyzed.
The ADAMS virtual prototyping software is applied to study the commercial aircraft emergency evacuation slide release process,and the motional coordination design technique of slide pack and aircraft translational open cabin door during slide release is analyzed in this paper. The simulation model of slide release is established with the restraints between slide pack and the fuselage structures which are considered as a contact-impact model. Slide release process is preferably simulated. Parameters that affect the slide release are simulated. The result shows that smoothly slide release can be achieved by lengthening release cable or increasing cabin door opening speed and the relationship between cabin door opening speed and the load on the girt when the slide pack falls outside of the sill is analyzed.
2014, 33(8): 1268-1271.
doi: 10.13433/j.cnki.1003-8728.2014.0832
Abstract:
Hoop truss deployable antenna(HTDA) is deployed by convolving the rope throughout the pipes. In order to accurately measure the length of rope which has been convolved,and to make the length of rope serve as a criterion of the antenna deployment,a deployable mechanism which can array the rope regularly is designed. The mechanism uses the original electromotor to draw the rope arraying regularly on the wheel by transforming the rotational movement of electromotor into arthrodia reciprocating in a beeline through a gear-box,The simulation analysis of dynamics and the function experiments prove that the mechanism can run steadily with payload and the rope can be arrayed regularly.
Hoop truss deployable antenna(HTDA) is deployed by convolving the rope throughout the pipes. In order to accurately measure the length of rope which has been convolved,and to make the length of rope serve as a criterion of the antenna deployment,a deployable mechanism which can array the rope regularly is designed. The mechanism uses the original electromotor to draw the rope arraying regularly on the wheel by transforming the rotational movement of electromotor into arthrodia reciprocating in a beeline through a gear-box,The simulation analysis of dynamics and the function experiments prove that the mechanism can run steadily with payload and the rope can be arrayed regularly.
2014, 33(8): 1272-1276.
doi: 10.13433/j.cnki.1003-8728.2014.0833
Abstract:
The rivet flexibility is an important quantity in the aircraft structure strength analysis,which is measured by the loading-deformation curve(p-δ curve for short) in practice. The p-δ curve for the rivet of lap metallic joints is investigated by using FEM. First,the mechanic model for analyzing the rivet deformation is proposed,in which the contact and friction of the rivet with rivet hole are considered. Then the influence of the different friction coefficients and metallic panel thicknesses on the rivet deformation is carried out. Finally,the model is validated by comparing the calculated with the testing results. It shows that both results agree well,which verifies that the present finite element model is reasonable and reliable. The present modeling can be used to analyze the p-δ curve for the other type of rivet.
The rivet flexibility is an important quantity in the aircraft structure strength analysis,which is measured by the loading-deformation curve(p-δ curve for short) in practice. The p-δ curve for the rivet of lap metallic joints is investigated by using FEM. First,the mechanic model for analyzing the rivet deformation is proposed,in which the contact and friction of the rivet with rivet hole are considered. Then the influence of the different friction coefficients and metallic panel thicknesses on the rivet deformation is carried out. Finally,the model is validated by comparing the calculated with the testing results. It shows that both results agree well,which verifies that the present finite element model is reasonable and reliable. The present modeling can be used to analyze the p-δ curve for the other type of rivet.
2014, 33(8): 1277-1280.
doi: 10.13433/j.cnki.1003-8728.2014.0834
Abstract:
It is very difficult to measure the stress distribution of gas turbine operating blade of tenon,an experiment method is proposed and realized by photoelastic frozen experiment. A few photoelastic models were designed and blanks were casted by vacuum pouring system,then,the blanks were machined by computer numerical control milling technology. The photoelastic experiment was accomplished by using a modularized and assembled unit,stress distribution of gas turbine operating blade tenon was obtained through slicing and stress analyses. The effectiveness of the experiment is proved by finite element computation results. The photoelastic frozen experiment provides reliable basis for strength and life analysis of gas turbine operating blade tenon of aeroengine.
It is very difficult to measure the stress distribution of gas turbine operating blade of tenon,an experiment method is proposed and realized by photoelastic frozen experiment. A few photoelastic models were designed and blanks were casted by vacuum pouring system,then,the blanks were machined by computer numerical control milling technology. The photoelastic experiment was accomplished by using a modularized and assembled unit,stress distribution of gas turbine operating blade tenon was obtained through slicing and stress analyses. The effectiveness of the experiment is proved by finite element computation results. The photoelastic frozen experiment provides reliable basis for strength and life analysis of gas turbine operating blade tenon of aeroengine.
