2001 Vol.14(4)
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2001, 15(4).
Abstract:
The middle-convex and varying ellipse piston is the key component of an internal-combustion engine. In general, the piston is machined by non-circular section CNC lathe, but the measuring of piston profile is manipulated by off-line. Because the off-line measuring rederence is different from the machining reference, the measurement result is diverse from the actual. Measurement result is diverse from the actual dimension. A new mehtod to measure the middle-convex and varying ellipse piston profile, which is known as on-line measuring, is presented. By using this kind of method, the high measurement accuracy can be gained, as well as meeting the production requirement.
The middle-convex and varying ellipse piston is the key component of an internal-combustion engine. In general, the piston is machined by non-circular section CNC lathe, but the measuring of piston profile is manipulated by off-line. Because the off-line measuring rederence is different from the machining reference, the measurement result is diverse from the actual. Measurement result is diverse from the actual dimension. A new mehtod to measure the middle-convex and varying ellipse piston profile, which is known as on-line measuring, is presented. By using this kind of method, the high measurement accuracy can be gained, as well as meeting the production requirement.
INFILTRATION KINETICS MODEL OF LIQUID METAL INTO A FIBROUS PREFORM IN CENTRIFUGAL ACCELERATING FIELD
2001, 15(4).
Abstract:
The infiltration kinetics of the metal melt into a fibrous preform in centrifugal accelerating field is analyzed on the basis of Darcy's law and the assumption that the fibrous preform is treated as "bundle of capillaries".The critical rotating speed is analyzed with the established model. The influences of the metal mass,the rotating speed of the equipment, the casting height, the original outer radius of the metal melt and the fibrous volume fraction in fibrous preform on infilatration are studied. The result show that the critical rotating speed is dependent on critical pressure,casting height,metal melt mass and the character of fibrous preform. With the increase in the metal melt mass,rotating speed of the equipment and original outer radius of the metal melt,or the decrease in casting height and fibrous volume fraction in fibrous of the metal melt, or the decrease in casting height and fibrous volume fraction in fibrous preform,infiltration of metal melt for fibrous preform becomes easier.
The infiltration kinetics of the metal melt into a fibrous preform in centrifugal accelerating field is analyzed on the basis of Darcy's law and the assumption that the fibrous preform is treated as "bundle of capillaries".The critical rotating speed is analyzed with the established model. The influences of the metal mass,the rotating speed of the equipment, the casting height, the original outer radius of the metal melt and the fibrous volume fraction in fibrous preform on infilatration are studied. The result show that the critical rotating speed is dependent on critical pressure,casting height,metal melt mass and the character of fibrous preform. With the increase in the metal melt mass,rotating speed of the equipment and original outer radius of the metal melt,or the decrease in casting height and fibrous volume fraction in fibrous of the metal melt, or the decrease in casting height and fibrous volume fraction in fibrous preform,infiltration of metal melt for fibrous preform becomes easier.
2001, 15(4).
Abstract:
A novel approach of printed circuit board (PCB)image locating is presented. Based on the rectangle mark image edge of PCB, the features is used to describe the image edge and the fractal properby of image edage edge is analyzed. It is proved that the rectangle mark image dege of PCB has some fractal features. A method of deleting unordinary curve noise and compensating the length of the fractal curve is put forward, which can get the fractal dimension value from one complex edge fractal property curve. The relation between the dimension of the fractal curve and the turning angle of imagre can be acquired from an equation, as a result, the angle value of the PCB image is got exactly. A real image edge analysis result confirms that the method based on the fractal theory is a new powerful tool for angle locating on PCB and related image area.
A novel approach of printed circuit board (PCB)image locating is presented. Based on the rectangle mark image edge of PCB, the features is used to describe the image edge and the fractal properby of image edage edge is analyzed. It is proved that the rectangle mark image dege of PCB has some fractal features. A method of deleting unordinary curve noise and compensating the length of the fractal curve is put forward, which can get the fractal dimension value from one complex edge fractal property curve. The relation between the dimension of the fractal curve and the turning angle of imagre can be acquired from an equation, as a result, the angle value of the PCB image is got exactly. A real image edge analysis result confirms that the method based on the fractal theory is a new powerful tool for angle locating on PCB and related image area.
2001, 15(4).
Abstract:
A scanning mear-field acoustic microscopy(SNAM)used in imaging the topography of precise surfaces is presented. As a micro-force sensor, a non-encapsulated 1 MHz quartz resonator is damped by hydrodynamic forces when approaching an object. Thus the oscillating characteristics of the leg of the quartz resonator change. While measuring the decrease of the amplitude of vibrating ,the shape of the object can be obtained. Based on the analyses of the principle and key parameters of SNAM, a SNAM is exploited. A lateral resolution of 0.5m and vertical resolutionm of 2 nm has been achieved in the experiments.
A scanning mear-field acoustic microscopy(SNAM)used in imaging the topography of precise surfaces is presented. As a micro-force sensor, a non-encapsulated 1 MHz quartz resonator is damped by hydrodynamic forces when approaching an object. Thus the oscillating characteristics of the leg of the quartz resonator change. While measuring the decrease of the amplitude of vibrating ,the shape of the object can be obtained. Based on the analyses of the principle and key parameters of SNAM, a SNAM is exploited. A lateral resolution of 0.5m and vertical resolutionm of 2 nm has been achieved in the experiments.
2001, 15(4).
Abstract:
An account of numerical solutions to the isothermal and flooded elastohydrodynamic lubrication(Fhl)of a logarithmic profile roller, which is rolling over a flat plane, is given. The analysis takes account of sideways flow of lubricant in the inlet region of the contact. When the results are presented in suitable non-dimensional groups, it is shown that more uniformly pressure and shape of the film distribution in axial direction is taken place under light loading. As the increase of the load, the end closure is displayed and the oil pressure rises sharply at the ends. The seal action formed by the end closure makes the film thickness a little. And the minimum film thickness is transferred from the central to the ends and the value is reduced rapidly. As the increase of the speed, the end closure becomes much serious. The optimum crowing value obtained in EHL state is sarger than the design value obtained in elastostatic contact state for the same working cinditions. In order to verify the correctmess of theory, optical interferometry is applied to measure the oil film thickness between a logarithmic profiled roller and a glass plate under pure rolling conditions.It is found the agreement between numerical solutions and experiments is very good.
An account of numerical solutions to the isothermal and flooded elastohydrodynamic lubrication(Fhl)of a logarithmic profile roller, which is rolling over a flat plane, is given. The analysis takes account of sideways flow of lubricant in the inlet region of the contact. When the results are presented in suitable non-dimensional groups, it is shown that more uniformly pressure and shape of the film distribution in axial direction is taken place under light loading. As the increase of the load, the end closure is displayed and the oil pressure rises sharply at the ends. The seal action formed by the end closure makes the film thickness a little. And the minimum film thickness is transferred from the central to the ends and the value is reduced rapidly. As the increase of the speed, the end closure becomes much serious. The optimum crowing value obtained in EHL state is sarger than the design value obtained in elastostatic contact state for the same working cinditions. In order to verify the correctmess of theory, optical interferometry is applied to measure the oil film thickness between a logarithmic profiled roller and a glass plate under pure rolling conditions.It is found the agreement between numerical solutions and experiments is very good.
2001, 15(4).
Abstract:
A particulate separation system that can be used to study the characteristics of the diesel particulate agglomeration and cyclone separation is developed. It includes a diesel particulate agglomerator and a cyclone separator mainly. A preliminary investigation on the cyclone separation technology for controlling the exhaust particulate from a diesel engine is conducted. The experimental results show that the diameter distribution of the diesel particulate is changed after they pass through the agglomerator, almost 30%-40% of the particulate agglomerated from less than 1.0 m to larger than 1.0 ,this change contributes to trap diesel particulate. With this system installed on the exhaust pipe of a single-cylinder engine, the particulate separation efficiency is around 40%-60% under typical engine running condition. The back-pressure of this system is less than 5 kPa on full load condition, much less than that of other methods of particulate filtration. This technology has the possibility to open a new prospect for particulate reduction because of its simplicity, reliability and low resistance.
A particulate separation system that can be used to study the characteristics of the diesel particulate agglomeration and cyclone separation is developed. It includes a diesel particulate agglomerator and a cyclone separator mainly. A preliminary investigation on the cyclone separation technology for controlling the exhaust particulate from a diesel engine is conducted. The experimental results show that the diameter distribution of the diesel particulate is changed after they pass through the agglomerator, almost 30%-40% of the particulate agglomerated from less than 1.0 m to larger than 1.0 ,this change contributes to trap diesel particulate. With this system installed on the exhaust pipe of a single-cylinder engine, the particulate separation efficiency is around 40%-60% under typical engine running condition. The back-pressure of this system is less than 5 kPa on full load condition, much less than that of other methods of particulate filtration. This technology has the possibility to open a new prospect for particulate reduction because of its simplicity, reliability and low resistance.
2001, 15(4).
Abstract:
Development of complicated products is a project of system engineering. It involves extensive and complicated knowledge, design methods and auxiliary technology.Various factors affect each other. So,modern product development is a typical group problem with distributed and dynamic features. It is apparent superiority to solve this problem with a multi-agent system representing various knowledge domains. Distributed artificial intelligence knowledge being used, the multi-agent collaborative design system concept and model based on Internet environment are put forward. The realizing method of product developing agents, interactive process among multi-agents, and organization and implementing of the design project of the multi-agent collaborative design system are discussed in detail. Application examples are also presented.
Development of complicated products is a project of system engineering. It involves extensive and complicated knowledge, design methods and auxiliary technology.Various factors affect each other. So,modern product development is a typical group problem with distributed and dynamic features. It is apparent superiority to solve this problem with a multi-agent system representing various knowledge domains. Distributed artificial intelligence knowledge being used, the multi-agent collaborative design system concept and model based on Internet environment are put forward. The realizing method of product developing agents, interactive process among multi-agents, and organization and implementing of the design project of the multi-agent collaborative design system are discussed in detail. Application examples are also presented.
2001, 15(4).
Abstract:
The superplasticity in SiCp/Al-alloy and SiCp/Al-Li Composites isintroduced. The composites are prepared by power metallurgy and cast methods. The superplastic parameters are measured. Superplastic treatment processing, secondry plastic working and the study of mirostructure are conducted.
The superplasticity in SiCp/Al-alloy and SiCp/Al-Li Composites isintroduced. The composites are prepared by power metallurgy and cast methods. The superplastic parameters are measured. Superplastic treatment processing, secondry plastic working and the study of mirostructure are conducted.
2001, 15(4).
Abstract:
According to the characteristics of electric arc spraying technology and abrasion of boiler piping, a flux-cored wire SMD 45 for electric arc spraying is developed. The experimental results show that the surface hardness of the coating reaches 60~65 HR and the adhesive strength between the coating and base is 23~28 Mpa. The wearability of the coating sprayed by the wire is 5 times than than of ordinary steel pipe. Applying the wire to the heated surface, the life of the economizer pipe is doubly increasecd. No local desquamation, rust and abrasion can be examined during more than one year's service.
According to the characteristics of electric arc spraying technology and abrasion of boiler piping, a flux-cored wire SMD 45 for electric arc spraying is developed. The experimental results show that the surface hardness of the coating reaches 60~65 HR and the adhesive strength between the coating and base is 23~28 Mpa. The wearability of the coating sprayed by the wire is 5 times than than of ordinary steel pipe. Applying the wire to the heated surface, the life of the economizer pipe is doubly increasecd. No local desquamation, rust and abrasion can be examined during more than one year's service.
2001, 15(4).
Abstract:
Vortex street flowmeter has been used in steady flow measurement for about three decades. The benefits of this type of flowmeter include high accuracy, good linearty, wide measuring range, and excellent reliability. However ,in unsteady flow measurement,the pressure disturbance as well as the noise from the system or surrounding can reduce the signal-to-noise ratio of the flowmeter seriously. Aimed to use vortex street flowmeters in unsteady flow measurment, the characteristics of the vortex shedding induced hydrodynamic vibration around the prism bluff body in a vortex street flowmeter are investigated numerically and by expriments. The results show that the hydrodynamic vibrations with 180 phase shift occur at the axisymmetric points of the channel around the bluff body. The most intense vibration occurs at the points on the lateral faces close to the base of the prism. The results provide therefore a useful reference for developing an anti-interference vortex flowmeter using the differential sensing technique.
Vortex street flowmeter has been used in steady flow measurement for about three decades. The benefits of this type of flowmeter include high accuracy, good linearty, wide measuring range, and excellent reliability. However ,in unsteady flow measurement,the pressure disturbance as well as the noise from the system or surrounding can reduce the signal-to-noise ratio of the flowmeter seriously. Aimed to use vortex street flowmeters in unsteady flow measurment, the characteristics of the vortex shedding induced hydrodynamic vibration around the prism bluff body in a vortex street flowmeter are investigated numerically and by expriments. The results show that the hydrodynamic vibrations with 180 phase shift occur at the axisymmetric points of the channel around the bluff body. The most intense vibration occurs at the points on the lateral faces close to the base of the prism. The results provide therefore a useful reference for developing an anti-interference vortex flowmeter using the differential sensing technique.
2001, 15(4).
Abstract:
A simulating experimental device for journal bearings of engines is established by use of the mechanism of ultrasonic vibration. This device can make the pressure insied the oil film changed at ultrasonic frequency, which enable the specimen surface to be damaged by cavitation erosion in a comparatively short time. Connecting with the bubbly oil-producing device, this rig can investigate the influence of bubbly oil in the cavitation erosion. Through datailed experimental research it is found that the bubbly oil decreases the cavitation erosion in journal bearings of engines. This result is analyzed reasonably from mechanism of cavitation erosion.
A simulating experimental device for journal bearings of engines is established by use of the mechanism of ultrasonic vibration. This device can make the pressure insied the oil film changed at ultrasonic frequency, which enable the specimen surface to be damaged by cavitation erosion in a comparatively short time. Connecting with the bubbly oil-producing device, this rig can investigate the influence of bubbly oil in the cavitation erosion. Through datailed experimental research it is found that the bubbly oil decreases the cavitation erosion in journal bearings of engines. This result is analyzed reasonably from mechanism of cavitation erosion.
2001, 15(4).
Abstract:
An experimental study on cuttig amorphous alloy at nanometer scale is conducted by applying the principle and technology of scanning probe microscope(SPM).It is revealed from the experiments that cutting inside SPM is an excellent and direct way to research the material removal process at small size. Based on the experimental results, the chip formation mechanism for the cutting of amorphous alloy is discussed. It is found that the deformation along the direction of chip flow occurs ahead of the appearance of localized shear, and a simplified geometrical model is proposed to illustrate the deformation.
An experimental study on cuttig amorphous alloy at nanometer scale is conducted by applying the principle and technology of scanning probe microscope(SPM).It is revealed from the experiments that cutting inside SPM is an excellent and direct way to research the material removal process at small size. Based on the experimental results, the chip formation mechanism for the cutting of amorphous alloy is discussed. It is found that the deformation along the direction of chip flow occurs ahead of the appearance of localized shear, and a simplified geometrical model is proposed to illustrate the deformation.
2001, 15(4).
Abstract:
A neural network approach is employed to deal with blending problem with surface construction based on digitized points, and some telated computational cases are presented. Compared with the NURBS method, this neural network based approach doesn't need the complex formula derivation as long as a limited number of offset points are got and its accurcy can meet the general engineering needs.
A neural network approach is employed to deal with blending problem with surface construction based on digitized points, and some telated computational cases are presented. Compared with the NURBS method, this neural network based approach doesn't need the complex formula derivation as long as a limited number of offset points are got and its accurcy can meet the general engineering needs.
2001, 15(4).
Abstract:
A colored-timed Petri net(CTPN)modeling technique is developed for flexible assembly system(FAS). In particular, one section is devoted to the deadlock nodel based on the Petri net. The rule of the deadlock error recovery is given. Through the analysis of the behavioral properites of the FAS with the deadlock recovery model, the deadlock problem would be solved in the system.
A colored-timed Petri net(CTPN)modeling technique is developed for flexible assembly system(FAS). In particular, one section is devoted to the deadlock nodel based on the Petri net. The rule of the deadlock error recovery is given. Through the analysis of the behavioral properites of the FAS with the deadlock recovery model, the deadlock problem would be solved in the system.
2001, 15(4).
Abstract:
Based on the object-oriented data structure of Voronoi diagram, the algorithm of the trimmed offset generationg and the optimal tool path planning of the pocket machining for multiply connected polygonal domains are studied. The intersection state transition rule is improved in this algorithm. The intersection is between the trimmed offsets and Voronoi polygon. On this basis, the trimmed offset generating and the optimal tool path planning are made with three stacks(I-stack, C-stack and P-stack)in different monotonous pouches of Voronoi diagram. At the same time, a merging method of Voronoi diagram and offsets generating for multiply connected polygonal domains is also presented. The above algorithms have been implemented in NC machining successfully, and the efficiency is fully verified.
Based on the object-oriented data structure of Voronoi diagram, the algorithm of the trimmed offset generationg and the optimal tool path planning of the pocket machining for multiply connected polygonal domains are studied. The intersection state transition rule is improved in this algorithm. The intersection is between the trimmed offsets and Voronoi polygon. On this basis, the trimmed offset generating and the optimal tool path planning are made with three stacks(I-stack, C-stack and P-stack)in different monotonous pouches of Voronoi diagram. At the same time, a merging method of Voronoi diagram and offsets generating for multiply connected polygonal domains is also presented. The above algorithms have been implemented in NC machining successfully, and the efficiency is fully verified.
2001, 15(4).
Abstract:
It is studied how the aluminum foil chatter mark is produced and controlled. The stableness of hydraulic AGC system, fluid vibration of capsule system, and electromechanical coupling of AC/AC VVVF system and de-coupling are also studied. It is shown that rolling mill design should go to system dynamic design from traditional design. The framed drawing of system dynamic design program is presented.
It is studied how the aluminum foil chatter mark is produced and controlled. The stableness of hydraulic AGC system, fluid vibration of capsule system, and electromechanical coupling of AC/AC VVVF system and de-coupling are also studied. It is shown that rolling mill design should go to system dynamic design from traditional design. The framed drawing of system dynamic design program is presented.
2001, 15(4).
Abstract:
By the bond graph theory, a bond graph analysis model of continuously variable transmission is established. On the basis of improving the ratio change response and reducing the engine torque response lag in normal control, a new synthetic control algorithm is developed. By analyzing the engine driving torque characteristics and the transmission inertia torque while ratio is changed under transient condition, the compensation value for engine driving torque is presented. The simulation result shows that by this compensation control algorithm the engine torque response lag can be reduced and the driving torque response can be improved effectively.
By the bond graph theory, a bond graph analysis model of continuously variable transmission is established. On the basis of improving the ratio change response and reducing the engine torque response lag in normal control, a new synthetic control algorithm is developed. By analyzing the engine driving torque characteristics and the transmission inertia torque while ratio is changed under transient condition, the compensation value for engine driving torque is presented. The simulation result shows that by this compensation control algorithm the engine torque response lag can be reduced and the driving torque response can be improved effectively.
2001, 15(4).
Abstract:
To deal with a bottom-up process model for design reuses a specific extended house of quality(EHOQ)is proposed. Two kinds of supported functions, basic supported functions and new supported functions, are defined. Two processes to determine two kinds of functions are presented. A kind of EHOQ matrix for a company is given and its management steps are studied.
To deal with a bottom-up process model for design reuses a specific extended house of quality(EHOQ)is proposed. Two kinds of supported functions, basic supported functions and new supported functions, are defined. Two processes to determine two kinds of functions are presented. A kind of EHOQ matrix for a company is given and its management steps are studied.
2001, 15(4).
Abstract:
The burr is one of the common phenomena occurring in metal cutting operations. The mathematical-mechanical model of two side-direction burr formation and transformation is established with plane stress-strain theory, based on the orthogonal cutting. The main laws of formation and change of the burr are revealed, and it is confirmed by experiment result, which first realizes prediction of the forming and changing of the two side-direction burr in metal cutting operation.
The burr is one of the common phenomena occurring in metal cutting operations. The mathematical-mechanical model of two side-direction burr formation and transformation is established with plane stress-strain theory, based on the orthogonal cutting. The main laws of formation and change of the burr are revealed, and it is confirmed by experiment result, which first realizes prediction of the forming and changing of the two side-direction burr in metal cutting operation.
2001, 15(4).
Abstract:
The rotating disk is a basic machine part that is used widely in industry. The motion equation is transformed into the dynamic equation in real modal space. The personating intelligent integration is introduced to improve the existing control method. These modes that affect the transverse vibration mainly are included to simulate the vibration of rotating disk, and two methods are applied separately on condition that the sensor and the actuator are collocated and noncollocated. The results obtained by all-sided simulations show that the new method can obtain better control effect, especially when the sensor and the actuator are non-collocate.
The rotating disk is a basic machine part that is used widely in industry. The motion equation is transformed into the dynamic equation in real modal space. The personating intelligent integration is introduced to improve the existing control method. These modes that affect the transverse vibration mainly are included to simulate the vibration of rotating disk, and two methods are applied separately on condition that the sensor and the actuator are collocated and noncollocated. The results obtained by all-sided simulations show that the new method can obtain better control effect, especially when the sensor and the actuator are non-collocate.
2001, 15(4).
Abstract:
A numerical method of integration of Green's functions of strip element method(SEM)is proposed. The response of ultrasonic source generated by a transducer on the surface of a multiply composite plate containing a delamination is analyzed by the use of SEM. The numerical results show that the scanning features of the ultrasonic waves may be used to identify the delamination inside the composite plate.
A numerical method of integration of Green's functions of strip element method(SEM)is proposed. The response of ultrasonic source generated by a transducer on the surface of a multiply composite plate containing a delamination is analyzed by the use of SEM. The numerical results show that the scanning features of the ultrasonic waves may be used to identify the delamination inside the composite plate.
2001, 15(4).
Abstract:
A novel variable displacement compressor(VDC) for automotive air conditioner(AAC) is introduced, which inherits the advantages of common wobble plate type VDC. It has fewer parts and makes less noise, and instead of pneumatic valve the displacement is controlled by electronic control valve. In order to know the control mechanism well and get a good control effect, a mathematical model for the variable displacement mechanism is developed according to the geometrical and kinemaatical information of the compressor. Using the model, the effect of relevant parameters on variable displace control is estimated. It is helpful to make the optimum decision in the flow control of AAC.As the novel displacement control device, the structure and control rule of electronic control valve is introduced. It can get better effect than the conventional pneumatic valves. And by using this new electronic control device, the optimum systemiccontrol of AAC is avaiblable.
A novel variable displacement compressor(VDC) for automotive air conditioner(AAC) is introduced, which inherits the advantages of common wobble plate type VDC. It has fewer parts and makes less noise, and instead of pneumatic valve the displacement is controlled by electronic control valve. In order to know the control mechanism well and get a good control effect, a mathematical model for the variable displacement mechanism is developed according to the geometrical and kinemaatical information of the compressor. Using the model, the effect of relevant parameters on variable displace control is estimated. It is helpful to make the optimum decision in the flow control of AAC.As the novel displacement control device, the structure and control rule of electronic control valve is introduced. It can get better effect than the conventional pneumatic valves. And by using this new electronic control device, the optimum systemiccontrol of AAC is avaiblable.
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