1991 Vol.4(1)
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1991, 5(1).
Abstract:
A thermal-partial elastohydrodynamic lubrication (PEHL) problem of heavily loaded line contacts was analyzed and the full-numerical results were given. The influences of operating and surface topographic conditions on the nominal film profile, pressure and temperature distributios of lubricant and solid surfaces as well as tractios upon contact area were concertrated. The lubrication characteristics of thermal PEHL were revealed in this paper.
A thermal-partial elastohydrodynamic lubrication (PEHL) problem of heavily loaded line contacts was analyzed and the full-numerical results were given. The influences of operating and surface topographic conditions on the nominal film profile, pressure and temperature distributios of lubricant and solid surfaces as well as tractios upon contact area were concertrated. The lubrication characteristics of thermal PEHL were revealed in this paper.
1991, 5(1).
Abstract:
The characteristics of transient rheological thermal elastohydrodynamic lubrication film between two infinitely long cylinders are analyzed in this paper.It is found that,when the ratio of the squeezing velocity to the entraining velocity is larger than 0.03, the behaviour of general transient film is quite similar to that of the pure squeeze film, of which the pressure curve is less than 0.003, the behaviour of general transient film is quite similar to that of the steady state one, an evident pressure spike locating in the outlet region can commonly be observed.
The characteristics of transient rheological thermal elastohydrodynamic lubrication film between two infinitely long cylinders are analyzed in this paper.It is found that,when the ratio of the squeezing velocity to the entraining velocity is larger than 0.03, the behaviour of general transient film is quite similar to that of the pure squeeze film, of which the pressure curve is less than 0.003, the behaviour of general transient film is quite similar to that of the steady state one, an evident pressure spike locating in the outlet region can commonly be observed.
1991, 5(1).
Abstract:
In this paper the theory has been presented on the relief grinding of ZC1 wheel hob. By this theory, ZC1 wheel hob has been first made in the People's Republic of China. The performance of the ZC1 worm decelerator produced to the theories of new technology of ZC1 worm transmission which involve the meshing theory, the parameter optimization, the controllable modification and the theory of hob relief grinding has come up to the advanced world level in the eighties.
In this paper the theory has been presented on the relief grinding of ZC1 wheel hob. By this theory, ZC1 wheel hob has been first made in the People's Republic of China. The performance of the ZC1 worm decelerator produced to the theories of new technology of ZC1 worm transmission which involve the meshing theory, the parameter optimization, the controllable modification and the theory of hob relief grinding has come up to the advanced world level in the eighties.
1991, 5(1).
Abstract:
Based on Drucker's isotropic yield function and Hosford's generalized isotropic yield criterion, anisotropic yield crierion considering the effect of the third invariant of stress tensor J3 is proposed, which contains two parameters n and C. The theoretical analyses of the effects of n and C on yield locus and the verifications by the experimental yield stress values showed that this new yield criterion may flexibly express a wide range of yield loci for anisotropic metals.
Based on Drucker's isotropic yield function and Hosford's generalized isotropic yield criterion, anisotropic yield crierion considering the effect of the third invariant of stress tensor J3 is proposed, which contains two parameters n and C. The theoretical analyses of the effects of n and C on yield locus and the verifications by the experimental yield stress values showed that this new yield criterion may flexibly express a wide range of yield loci for anisotropic metals.
1991, 5(1).
Abstract:
An NC auto-programming method is presented for free form surfaces. The surface forming and its adjusting and cutter path generating are introduced. A practical example is given too.
An NC auto-programming method is presented for free form surfaces. The surface forming and its adjusting and cutter path generating are introduced. A practical example is given too.
1991, 5(1).
Abstract:
This paper applies the regularization gradient algorithm for calculating the inverse problems of heat transfer to determine the thermophysical properties of test probes recommended by IFHT-TCQ. The results obtained provide reliable data for research into the cooling process of the standard probe.
This paper applies the regularization gradient algorithm for calculating the inverse problems of heat transfer to determine the thermophysical properties of test probes recommended by IFHT-TCQ. The results obtained provide reliable data for research into the cooling process of the standard probe.
1991, 5(1).
Abstract:
Based on the mechanical impedance analysis of the rapier loom's vibration isolation system in detail and the identification of the disturb sources of loom, a completely new idea is presented here for the optimum design of parameters of the loom's impact isolator. A straight forward way is suggested for general impact vibration isolator design. The new methods above have been verified vividly by a large amount of analytical detail in the numerical computation of vibration isolating model and a successful practice of the impact isolation of the rapier loom's mounted on the second floor.
Based on the mechanical impedance analysis of the rapier loom's vibration isolation system in detail and the identification of the disturb sources of loom, a completely new idea is presented here for the optimum design of parameters of the loom's impact isolator. A straight forward way is suggested for general impact vibration isolator design. The new methods above have been verified vividly by a large amount of analytical detail in the numerical computation of vibration isolating model and a successful practice of the impact isolation of the rapier loom's mounted on the second floor.
1991, 5(1).
Abstract:
The electric block diagram of newly developed pulse width modulated inverting arc welding power source is given in this paper after the necessity of developing transistor-inverter arc welding power source has been briefly clarified. The principle of this power source is analyzed from view-point of obtaining constant-current characteristic. Secondly, theoretical analyses are made to slelct inverting frequency. And the formula of reactance of output reactor is derived from calculating the dynamic process of welding current. Finally, based on the equivalent circuit of high-frequency transformer, the current variation under the action of rectangular pulse sequence voltage is analyzed. The cause and harmfulness of magnetic biasing phenomenon of high-frequency transformer are also discussed.
The electric block diagram of newly developed pulse width modulated inverting arc welding power source is given in this paper after the necessity of developing transistor-inverter arc welding power source has been briefly clarified. The principle of this power source is analyzed from view-point of obtaining constant-current characteristic. Secondly, theoretical analyses are made to slelct inverting frequency. And the formula of reactance of output reactor is derived from calculating the dynamic process of welding current. Finally, based on the equivalent circuit of high-frequency transformer, the current variation under the action of rectangular pulse sequence voltage is analyzed. The cause and harmfulness of magnetic biasing phenomenon of high-frequency transformer are also discussed.
1991, 5(1).
Abstract:
The present paper deals with the research on the characteristics and balancing of the shaking force and shaking moment of and elastic 4-bar linkage. The differential equations of the system are established using the finite element method. The natural frequencies, the sensitivity of fundamental frequency, and the amplitude-frequency responses of the shaking force and the shaking moment of the linkage are calculated and analyzed. Some methods which can reduce the unbalance of elastic mechanisms are proposed.
The present paper deals with the research on the characteristics and balancing of the shaking force and shaking moment of and elastic 4-bar linkage. The differential equations of the system are established using the finite element method. The natural frequencies, the sensitivity of fundamental frequency, and the amplitude-frequency responses of the shaking force and the shaking moment of the linkage are calculated and analyzed. Some methods which can reduce the unbalance of elastic mechanisms are proposed.
1991, 5(1).
Abstract:
In this paper, the CASTOR large-scale ductile iron cask made in Federal Republic of Germany was taken as an object of our study. A cubic simulative casting 400 mm in length solidified along one dimension was investigated. According to various cooling one dimension was imvestigated. According to various cooling conditions, we determined the solidification curves in various positions and dynamic solidification curves in the casting and analyzed the solidification characteristics of the heavy ductile iron casing and the conditions of its formation. Meanwhile we discussed the law of variation of casting thickness, solidification time and graphite morphology. For ensuring the quality of casting, this paper provides a reliable basis with respect to cooling condition.
In this paper, the CASTOR large-scale ductile iron cask made in Federal Republic of Germany was taken as an object of our study. A cubic simulative casting 400 mm in length solidified along one dimension was investigated. According to various cooling one dimension was imvestigated. According to various cooling conditions, we determined the solidification curves in various positions and dynamic solidification curves in the casting and analyzed the solidification characteristics of the heavy ductile iron casing and the conditions of its formation. Meanwhile we discussed the law of variation of casting thickness, solidification time and graphite morphology. For ensuring the quality of casting, this paper provides a reliable basis with respect to cooling condition.
1991, 5(1).
Abstract:
This paper presents a reliability design method of steam turbine blades. It is based on present-day desibn criteria of vibration strength, but considers vibration frequencies and excition force frequencies and safety ratios to be random variables according to actual conditions. Some blade reliability design examples are given.
This paper presents a reliability design method of steam turbine blades. It is based on present-day desibn criteria of vibration strength, but considers vibration frequencies and excition force frequencies and safety ratios to be random variables according to actual conditions. Some blade reliability design examples are given.
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