2000 Vol.13(4)
Display Mode： |
2000, 14(4).
Abstract:
The method of planning ecceleration is discussed to restrain the residual vibration of flexible arm. Based on the built mathematical model of the flexible arm, the equations of vibration with acceleration, vibration frequency, damping and time are obtained theoretically. According to the vibration frequency and damping, the suitable acceleration is executed experimentally to the flexible arm at the corresponding time. The result shows that this way can give rise to good effect to restrain the residual vibration.
The method of planning ecceleration is discussed to restrain the residual vibration of flexible arm. Based on the built mathematical model of the flexible arm, the equations of vibration with acceleration, vibration frequency, damping and time are obtained theoretically. According to the vibration frequency and damping, the suitable acceleration is executed experimentally to the flexible arm at the corresponding time. The result shows that this way can give rise to good effect to restrain the residual vibration.
2000, 14(4).
Abstract:
In order to realize high speed machining, the special requirements for feed transmission system of the CNC machine tool have to be satisfied . A high velocity feed unit driven by a induction linear motor is developed. The compositions of the high velocity CNC feed unit and main problems in the unit design are discussed.
In order to realize high speed machining, the special requirements for feed transmission system of the CNC machine tool have to be satisfied . A high velocity feed unit driven by a induction linear motor is developed. The compositions of the high velocity CNC feed unit and main problems in the unit design are discussed.
2000, 14(4).
Abstract:
Based on improved test rig with cooling system, the traction experiments for 4109 Chniese aviation lubricant are tested under various simulated working conditions. Both the experimental data thanks to their accuracy and stability and the better cooling effect of the electric shafts has given the rationality of the experimental rig a strong support. An empirical equation for calculating the traction coefficient of 4109 lubricant, which may be conveniently used for engineering application, is obtained. Furthermore, the rhelogical properties of the lubricant are investigated.
Based on improved test rig with cooling system, the traction experiments for 4109 Chniese aviation lubricant are tested under various simulated working conditions. Both the experimental data thanks to their accuracy and stability and the better cooling effect of the electric shafts has given the rationality of the experimental rig a strong support. An empirical equation for calculating the traction coefficient of 4109 lubricant, which may be conveniently used for engineering application, is obtained. Furthermore, the rhelogical properties of the lubricant are investigated.
2000, 14(4).
Abstract:
In order to improve the engineering performance of a novel hydraulic shock generator, the fluid flow inside its complex passages is numerically inestigated. The effects of the inlet flow velocity upon the turbulence intensity of the jet flow are analyzed. The calculated pressure loss is experimentally verified with the consideration of remperature determined viscosity shufting. The results are used as the reference in the further development of the hydraulic shock generator
In order to improve the engineering performance of a novel hydraulic shock generator, the fluid flow inside its complex passages is numerically inestigated. The effects of the inlet flow velocity upon the turbulence intensity of the jet flow are analyzed. The calculated pressure loss is experimentally verified with the consideration of remperature determined viscosity shufting. The results are used as the reference in the further development of the hydraulic shock generator
2000, 14(4).
Abstract:
The computer-controlled turning technique of shaped connection (keyless connection), shaft and hole, is discussed. By using the method, a clearance free fit with a taper is obtained. After the comparison of the mechanical behavior and the turning machinability of the contours, it is found that the present contour needs further improvement, and a new contour is presented.
The computer-controlled turning technique of shaped connection (keyless connection), shaft and hole, is discussed. By using the method, a clearance free fit with a taper is obtained. After the comparison of the mechanical behavior and the turning machinability of the contours, it is found that the present contour needs further improvement, and a new contour is presented.
2000, 14(4).
Abstract:
A model for the non-linear axial vibrations of the hydrodynamic thrust bearing-rotor system in a turboexpander is described. The axial transient process of the system is investigated. The time-dependent form of the Reynolds equation is solved by a finite difference method with successive overrelaxation scheme to obtain the hydrodynamic forces of the sector-shaped thrust bearing (SSTB). Using these forces, the equaiton of motion is solved by the fourth-order Runge-Kutta method and the Adams method to predict the transient behaviour of the thrust bearing-rotor system(TBRS). Also, the linearized siffness and damping coefficients of the oil film hydrodynamic SSTB are calculated. The analyses of the axial transient response of the system under both linear and non-linear conditions are performed. The non-linearity of oil film forces can significantly contribute to the axial transient response. Conclusions obtained can be applied for evaluation of the reliability of the TBRS.
A model for the non-linear axial vibrations of the hydrodynamic thrust bearing-rotor system in a turboexpander is described. The axial transient process of the system is investigated. The time-dependent form of the Reynolds equation is solved by a finite difference method with successive overrelaxation scheme to obtain the hydrodynamic forces of the sector-shaped thrust bearing (SSTB). Using these forces, the equaiton of motion is solved by the fourth-order Runge-Kutta method and the Adams method to predict the transient behaviour of the thrust bearing-rotor system(TBRS). Also, the linearized siffness and damping coefficients of the oil film hydrodynamic SSTB are calculated. The analyses of the axial transient response of the system under both linear and non-linear conditions are performed. The non-linearity of oil film forces can significantly contribute to the axial transient response. Conclusions obtained can be applied for evaluation of the reliability of the TBRS.
2000, 14(4).
Abstract:
A simple and reliable contact algorithm for static-implicit FE code is proposed. It can overcome miss-judgement and error-judgement, and improve convergence effectively, and can apply friction boundary condition conveniently. Based on the proposed contact algorithm, some typical sheet metal forming processes and one benchmark of NUMISHEET 93 are simulated by static-implicit FE code developed by the authors and their group.
A simple and reliable contact algorithm for static-implicit FE code is proposed. It can overcome miss-judgement and error-judgement, and improve convergence effectively, and can apply friction boundary condition conveniently. Based on the proposed contact algorithm, some typical sheet metal forming processes and one benchmark of NUMISHEET 93 are simulated by static-implicit FE code developed by the authors and their group.
2000, 14(4).
Abstract:
Guided by developing forging technology theory, designing rules on rotor forging process are summed up. Knowledge-based CAPP system for rotor forging is created. The system gives a rational and optimum process.
Guided by developing forging technology theory, designing rules on rotor forging process are summed up. Knowledge-based CAPP system for rotor forging is created. The system gives a rational and optimum process.
2000, 14(4).
Abstract:
A statistic linearization analysis method of bad nolinear hydraulic acitive damping suspension is provided. Also the optimum control strategy of semi-active suspension and graded control stategy bassed on it are put forward. Experimental researches are carried out on a 2 DOF (degree of freedom) hydraulic active damping suspension test system.The results showed that an excellent control effectiveness could be obtained by using statisitic linearization optimum control with unfortunely requests continuously regulation the damp in an accurate way and costs much in engineering application . On the contrary, the results also showed that graded control is more praticable which has a control effectiveness close to the optimum control and costs less.
A statistic linearization analysis method of bad nolinear hydraulic acitive damping suspension is provided. Also the optimum control strategy of semi-active suspension and graded control stategy bassed on it are put forward. Experimental researches are carried out on a 2 DOF (degree of freedom) hydraulic active damping suspension test system.The results showed that an excellent control effectiveness could be obtained by using statisitic linearization optimum control with unfortunely requests continuously regulation the damp in an accurate way and costs much in engineering application . On the contrary, the results also showed that graded control is more praticable which has a control effectiveness close to the optimum control and costs less.
2000, 14(4).
Abstract:
Based on gas dynamics, thermodynamics, fluid dynamics of multiphase systems and other theories,the dynamic analyses of the particle flying velocity in a high velocity oxygen fuel spray (HVOF) is accomplished. The relationships between the flying velocity of a particle and the flying time or flying length, particle size,hot gas velocity, pressure or density of the gas are proposed. Meanwhile , the influences of the velocity and mass rate of flow of the flame gas of a HVOF gun, and particle size on the particle flying velocity are discussed in detail . The dynamic pressure concept is introduced to express the flow capacity of hot gas of a HVOF gun, and the relationship between the dynamic pressure of a HVOF gun and the velocity of a particle for depositing is presented.
Based on gas dynamics, thermodynamics, fluid dynamics of multiphase systems and other theories,the dynamic analyses of the particle flying velocity in a high velocity oxygen fuel spray (HVOF) is accomplished. The relationships between the flying velocity of a particle and the flying time or flying length, particle size,hot gas velocity, pressure or density of the gas are proposed. Meanwhile , the influences of the velocity and mass rate of flow of the flame gas of a HVOF gun, and particle size on the particle flying velocity are discussed in detail . The dynamic pressure concept is introduced to express the flow capacity of hot gas of a HVOF gun, and the relationship between the dynamic pressure of a HVOF gun and the velocity of a particle for depositing is presented.
2000, 14(4).
Abstract:
The validity of a novel, direct and convenient method for micromechanical property measurements by beam bending using a nanoindenter is demonstrated. This method combines a very high load resolution with a nanoemtric precision in the determination of the microcantilever beam deflection. The method is described clearly. In the deflection of microbeams, the influence of the indenter tip pushing into the top of the microbeams and the curvature across its width must be considered. The measurements were made on single-layer, micro-thick, several kinds of width and length polysilicon beams that were fabricated using conventional integrated circuit (IC) fabrication techniques. The elastic of a polysilicon microcantilever beam will vary linearly with the force and the deformation is thought to be elastic. Furthermore, it suggests that Young modulus of the beam can be determined from the slope of this linear relation. From the load-deflection data acquired during bending the mechanical properties of the thin films were determined. Measured Young Modulus is 137 Gpa with approximately a 2.9%~ 6.3% difference in Young modulus.
The validity of a novel, direct and convenient method for micromechanical property measurements by beam bending using a nanoindenter is demonstrated. This method combines a very high load resolution with a nanoemtric precision in the determination of the microcantilever beam deflection. The method is described clearly. In the deflection of microbeams, the influence of the indenter tip pushing into the top of the microbeams and the curvature across its width must be considered. The measurements were made on single-layer, micro-thick, several kinds of width and length polysilicon beams that were fabricated using conventional integrated circuit (IC) fabrication techniques. The elastic of a polysilicon microcantilever beam will vary linearly with the force and the deformation is thought to be elastic. Furthermore, it suggests that Young modulus of the beam can be determined from the slope of this linear relation. From the load-deflection data acquired during bending the mechanical properties of the thin films were determined. Measured Young Modulus is 137 Gpa with approximately a 2.9%~ 6.3% difference in Young modulus.
2000, 14(4).
Abstract:
According to the demand of high reliability of the primary cyliner of the hydraulic press, the reliability model of the primary cylinder is built after its reliability analysis. The stress of the primary cylinder is analyzed by finite element softweare—MARC, and the struture reliability of the cylinder based on stress-strength model is predicted, which would provide the reference to the design.
According to the demand of high reliability of the primary cyliner of the hydraulic press, the reliability model of the primary cylinder is built after its reliability analysis. The stress of the primary cylinder is analyzed by finite element softweare—MARC, and the struture reliability of the cylinder based on stress-strength model is predicted, which would provide the reference to the design.
2000, 14(4).
Abstract:
A hysteric model is represented to describe the dependence of restoring force on deformation of pseudoelastic SMA. The dynamic response of the system is investigated by means of mathematical models. The result shows that this kind of vibration absorbing system can suppress vibration with large amplitude effectively. Furthermore, the vibration absorbing system can work in optimum state by adjusting temperature and using piezoelectric sensors and actuators.
A hysteric model is represented to describe the dependence of restoring force on deformation of pseudoelastic SMA. The dynamic response of the system is investigated by means of mathematical models. The result shows that this kind of vibration absorbing system can suppress vibration with large amplitude effectively. Furthermore, the vibration absorbing system can work in optimum state by adjusting temperature and using piezoelectric sensors and actuators.
E-mail Alerts
