1999 Vol.12(3)
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1999, 13(3).
Abstract:
A method of numerical simulation on solidification process of horizontally continuously cast round iron bar is developed, in which transient heat transfer equations are used and longitudinal heat conduction is taken into account. The interfacial heat-transfer coefficient between iron bar and graphite sleeve, which is determined by using a free thermal contraction method, is used as a boundary condition, and the whole system including iron bar, graphite sleeve and water cooled jacket is considered in heat transfer calculation. In the calculation, a stationary coordinate system and a moving one are used for graphite sleeve and iron bar respectively, in order to make the heat transfer equation applied in iron bar be simplified and the coupled calculation of temperature fields in both iron bar and graphite sleeve convenient. The developed method can be used to simulate solidification process of the iron bars with different diameters under different technological conditions.
A method of numerical simulation on solidification process of horizontally continuously cast round iron bar is developed, in which transient heat transfer equations are used and longitudinal heat conduction is taken into account. The interfacial heat-transfer coefficient between iron bar and graphite sleeve, which is determined by using a free thermal contraction method, is used as a boundary condition, and the whole system including iron bar, graphite sleeve and water cooled jacket is considered in heat transfer calculation. In the calculation, a stationary coordinate system and a moving one are used for graphite sleeve and iron bar respectively, in order to make the heat transfer equation applied in iron bar be simplified and the coupled calculation of temperature fields in both iron bar and graphite sleeve convenient. The developed method can be used to simulate solidification process of the iron bars with different diameters under different technological conditions.
1999, 13(3).
Abstract:
In order to solove the existing problems in computer vision in engineering application, a new theory, called computer pan-vision (CPV) theory, is put forward. The foundations and main concepts of this theory are presented. The purpose of CPV is to give a unified general realizable frame of computer vision in real engineering application, and study how to reduce the difficulty of vision problems by utilizing non-vision auxiliary information and human intelligence sufficiently.
In order to solove the existing problems in computer vision in engineering application, a new theory, called computer pan-vision (CPV) theory, is put forward. The foundations and main concepts of this theory are presented. The purpose of CPV is to give a unified general realizable frame of computer vision in real engineering application, and study how to reduce the difficulty of vision problems by utilizing non-vision auxiliary information and human intelligence sufficiently.
1999, 13(3).
Abstract:
An adaptive state feedback controller (ASFC) with Kalman filter observer is presented for machining process control. The state equations of the process are derived from the second order transfer function. The analysis shows that the machining process is observable and controllable. The state variables are estimated by a Kalman filter obesrver. The objective of adaptive control for the machining process is given as a desired second order system and the adaptive controller is considered as a trace system with non-zero reference input. Then the adaptive control law is calculated by poleassignment method in state space. The algorithms of the observer and controller are plugged into a real-time platform, intelligent machining module (IMM), as the plue-in-modules (PIMs) to build up the ASFC control system for off-line real time simulations and machining tests in the laboratory. The simulations and experiments under under different cutting conditions demonstrate that the controller is stable, reliable and robust.
An adaptive state feedback controller (ASFC) with Kalman filter observer is presented for machining process control. The state equations of the process are derived from the second order transfer function. The analysis shows that the machining process is observable and controllable. The state variables are estimated by a Kalman filter obesrver. The objective of adaptive control for the machining process is given as a desired second order system and the adaptive controller is considered as a trace system with non-zero reference input. Then the adaptive control law is calculated by poleassignment method in state space. The algorithms of the observer and controller are plugged into a real-time platform, intelligent machining module (IMM), as the plue-in-modules (PIMs) to build up the ASFC control system for off-line real time simulations and machining tests in the laboratory. The simulations and experiments under under different cutting conditions demonstrate that the controller is stable, reliable and robust.
1999, 13(3).
Abstract:
According to the rolling slippage of rolling mill drive trains, a nonlinear mechanical model for the drive is established and the asymptotic method is used to solve it. The conditions for the self-excited vibration are ascertained. A way calculating the upper and lower limit angular velocities between which the self-excited vibration can be aroused is presented, and also the relationship of rolling normal force, vibration arises is derived. The research project may provide a probability to prevent the system from instantaneous breakage due to the self-excited vibration.
According to the rolling slippage of rolling mill drive trains, a nonlinear mechanical model for the drive is established and the asymptotic method is used to solve it. The conditions for the self-excited vibration are ascertained. A way calculating the upper and lower limit angular velocities between which the self-excited vibration can be aroused is presented, and also the relationship of rolling normal force, vibration arises is derived. The research project may provide a probability to prevent the system from instantaneous breakage due to the self-excited vibration.
1999, 13(3).
Abstract:
A mathematical model of the electro-hydraulic speed control system with parallel pipelines on the dynamics of the system is studied. The simulation and the experiments are carried out for different length of pipelines. The results show that the appropriate adapting parallel pipelines can improve dynamic performance of the electro-hydraulic speed control system.
A mathematical model of the electro-hydraulic speed control system with parallel pipelines on the dynamics of the system is studied. The simulation and the experiments are carried out for different length of pipelines. The results show that the appropriate adapting parallel pipelines can improve dynamic performance of the electro-hydraulic speed control system.
1999, 13(3).
Abstract:
Reynolds equations of Ostwald non-Newtonian fluid in various zone of drawing process are derived. That the distribution figures of oil film thickness, pressure and inside stress are obtained by Ostwald non-Newtonian model and large strain elastic plastic finite element is analyzed by drawing examples.
Reynolds equations of Ostwald non-Newtonian fluid in various zone of drawing process are derived. That the distribution figures of oil film thickness, pressure and inside stress are obtained by Ostwald non-Newtonian model and large strain elastic plastic finite element is analyzed by drawing examples.
1999, 13(3).
Abstract:
A theoretical approach is presented to model the dynamic pressure-torpue response of Audi 100 disc brake. Transfer function of the brake is formed by regarding the brake as a proportional/delay system and the brake line as second-order system. Dynamic torque response can be obtained by solving equations. The approach is introduced to perform simulation test of anti-lock brakes by using KRAUSS tester. The theoretical and actual torque response are compared, the result is analyzed to examine the effectiveness and preciseness of the model developed.
A theoretical approach is presented to model the dynamic pressure-torpue response of Audi 100 disc brake. Transfer function of the brake is formed by regarding the brake as a proportional/delay system and the brake line as second-order system. Dynamic torque response can be obtained by solving equations. The approach is introduced to perform simulation test of anti-lock brakes by using KRAUSS tester. The theoretical and actual torque response are compared, the result is analyzed to examine the effectiveness and preciseness of the model developed.
1999, 13(3).
Abstract:
Dynamics of the 3-PRS spatial parallel mechanism is analyzed by finite element method. This spatial beam element is introduced and the equations of the motion of mechanisms with rigid links are derived using principle of virtual power. A computer program is developed according to the formulations and with which the numerical results of motion of the 3-RPS mechanism are presented.
Dynamics of the 3-PRS spatial parallel mechanism is analyzed by finite element method. This spatial beam element is introduced and the equations of the motion of mechanisms with rigid links are derived using principle of virtual power. A computer program is developed according to the formulations and with which the numerical results of motion of the 3-RPS mechanism are presented.
1999, 13(3).
Abstract:
A general finite strip analysis method is presented for the forming process analysis of channel steel. For the first time, a theoretical model of elastic-plastic large deformation spline finite strip method based on the updated-Lagrange method is introduced to metal forming field. The method is employed to analyze the displacement field, the stress field and the strain field betwwen two stands during channel steel forming process. The information is valuable to the production. It is proved that the method is available for the analysis of the complicated channel steel forming.
A general finite strip analysis method is presented for the forming process analysis of channel steel. For the first time, a theoretical model of elastic-plastic large deformation spline finite strip method based on the updated-Lagrange method is introduced to metal forming field. The method is employed to analyze the displacement field, the stress field and the strain field betwwen two stands during channel steel forming process. The information is valuable to the production. It is proved that the method is available for the analysis of the complicated channel steel forming.
1999, 13(3).
Abstract:
Based on theories of electrohydraulic servosystems and fluid dynamics, electrohydraulic servo-valves, the key parts of electrohydraulic servosystems, are analyzed in centrifugal force field. Forces acting on typical two-stage valves are formulated in sequence. Centrifugal force is included in equations. Conclusions from analysis and experimental data are shown as follows. Centrifugal acceleration is directly proportional to null shift with current and the scale factor is formulated. Methods reducing thd influence of centrifugal force are offered. The research is shortfall at home and abroad, and it is helpful to researchers who study electrohydraulic servo-valves in centrifugal force field.
Based on theories of electrohydraulic servosystems and fluid dynamics, electrohydraulic servo-valves, the key parts of electrohydraulic servosystems, are analyzed in centrifugal force field. Forces acting on typical two-stage valves are formulated in sequence. Centrifugal force is included in equations. Conclusions from analysis and experimental data are shown as follows. Centrifugal acceleration is directly proportional to null shift with current and the scale factor is formulated. Methods reducing thd influence of centrifugal force are offered. The research is shortfall at home and abroad, and it is helpful to researchers who study electrohydraulic servo-valves in centrifugal force field.
1999, 13(3).
Abstract:
Based on Besinger's model structure for shock absorbers in vehicles, seven parameter values are identified by a new procedure of fitting experiment data for the shock absorbers produced in Tianjin. Simulation results are basically in agreement with those of experiment. So the model and the new procedure are suitable at least for the products.
Based on Besinger's model structure for shock absorbers in vehicles, seven parameter values are identified by a new procedure of fitting experiment data for the shock absorbers produced in Tianjin. Simulation results are basically in agreement with those of experiment. So the model and the new procedure are suitable at least for the products.
1999, 13(3).
Abstract:
The lives of a batch of cutting tools are usually largely scattered. Tool reliability can thus be improved by screening with a proof test. Relationship between the after-test tool reliability and the stress level or the impacting cycles applied on the tool during the proof test is analysed. The results obtained from verification experiments agree well with the analysis.
The lives of a batch of cutting tools are usually largely scattered. Tool reliability can thus be improved by screening with a proof test. Relationship between the after-test tool reliability and the stress level or the impacting cycles applied on the tool during the proof test is analysed. The results obtained from verification experiments agree well with the analysis.
1999, 13(3).
Abstract:
A general expression for the power flow transmitted to a flexible seating via spring-like mounts from a rigid body excited by a harmonic off-centre force is developed. By calculating and analyzing the power flow frequency spectrum of a numerical example, some important influences offcentre force excitation on the power transimission as well as on the vibration isolation efficiency of asymmetrical flexible systems are demonstrated substantially.
A general expression for the power flow transmitted to a flexible seating via spring-like mounts from a rigid body excited by a harmonic off-centre force is developed. By calculating and analyzing the power flow frequency spectrum of a numerical example, some important influences offcentre force excitation on the power transimission as well as on the vibration isolation efficiency of asymmetrical flexible systems are demonstrated substantially.
1999, 13(3).
Abstract:
A new mechanism including a tilting minute adjustable major axis word-holder and a fine feed devece driven by piezocrystal actuators is put forward. A central spherical bearing structure is adopted to increase the rigidity of work-holder and a close-loop control feed device is used to improve the feed accuracy of diamond tool. Testing reaults demonstrate that the new mechanism can satisfy the needs of precision cutting of miniature lens.
A new mechanism including a tilting minute adjustable major axis word-holder and a fine feed devece driven by piezocrystal actuators is put forward. A central spherical bearing structure is adopted to increase the rigidity of work-holder and a close-loop control feed device is used to improve the feed accuracy of diamond tool. Testing reaults demonstrate that the new mechanism can satisfy the needs of precision cutting of miniature lens.
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