The numerical analysis on a shaft with rub-impact condition is done by using the finite difference method. The bending modes and the moment yaring along the shaft are described,to reveal the in crease pattern of sect...The numerical analysis on a shaft with rub-impact condition is done by using the finite difference method. The bending modes and the moment yaring along the shaft are described,to reveal the in crease pattern of sectional stress of the shaft. The result obtained in this paper can be used in explaining the phenomena of many breaking sections appeared in destructive failures of actual rotating machinery.展开更多
For the purpose of analyzing the torsional vibration caused by the gravitational unbalance torque arisen in a spindle system when it is machining heavy work piece,a 10-DOF lumped parameter model was made for the machi...For the purpose of analyzing the torsional vibration caused by the gravitational unbalance torque arisen in a spindle system when it is machining heavy work piece,a 10-DOF lumped parameter model was made for the machine tool spindle system with geared transmission.By using the elementary method and Runge-Kutta method in Matlab,the eigenvalue problem was solved and the pure torsional vibration responses were obtained and examined.The results show that the spindle system cannot operate in the desired constant rotating speed as far as the gravitational unbalance torque is engaged,so it may cause bad effect on machining accuracy.And the torsional vibration increases infinitely near the resonant frequencies,so the spindle system cannot operate normally during these spindle speed ranges.展开更多
In the framework of parallelism general relativity, the torsion axial-vector in the rotating gravitational field is studied in terms of the alternative Kerr tetrad. In thecase of the weak field and slow rotation appro...In the framework of parallelism general relativity, the torsion axial-vector in the rotating gravitational field is studied in terms of the alternative Kerr tetrad. In thecase of the weak field and slow rotation approximation, we obtain that the torsion axial-vector possesses the dipole-like structure. Furthermore, the effect of massive neutrino spin precession in this field is mentioned.展开更多
The paper presents the methodology and results of measurement designed to determine the effect of the rolling element separator （cage） at the frictional moment in ball bearings, The measurement was carried out on fo...The paper presents the methodology and results of measurement designed to determine the effect of the rolling element separator （cage） at the frictional moment in ball bearings, The measurement was carried out on four groups on bearing with different cages. Measurements were carried out on torque-meter STPM, a device that has been designed and manufactured at Kielce University of Technology. The measurement results showed that the type of cage used in ball bearings has a significant impact on the frictional moment. In addition, the results also confirm that the size of the curvature ratio and the accuracy of the races shape have a significant impact on the frictional moment.展开更多
The massless scalar quasiaormal modes （QNMs） of a stationary axisymmetric Einstein-Maxwell dilato-axioa （EMDA） black hole are calculated numerically using the continued fraction method first proposed by Leaver. Th...The massless scalar quasiaormal modes （QNMs） of a stationary axisymmetric Einstein-Maxwell dilato-axioa （EMDA） black hole are calculated numerically using the continued fraction method first proposed by Leaver. The fundamental quasinormal frequencies （slowly damped QNMs） are obtained and the peculiar behaviours of them are studied. It is shown that these frequencies depend on the dilaton parameter D, the rotational parameter a, the multiple moment l and the azimuthal number m, and have the same values with other authors at the Schwarzschild and Kerr limit.展开更多
The couple effect of soil displacement and axial load on the single inclined pile in cases of surcharge load and uniform soil movement is discussed in detail with the methods of full-scale field tests and finite eleme...The couple effect of soil displacement and axial load on the single inclined pile in cases of surcharge load and uniform soil movement is discussed in detail with the methods of full-scale field tests and finite element method. Parametric analyses including the degree of inclination and the distance between soil and pile are carried out herein. When the displacement of soil on the left side and right side of a pile is identical, deformation of a vertical pile and an inclined pile is highly close in both cases of surcharge load and uniform soil movement. When the couple effect of soil displacement and axial load occurs, settlement of an inclined pile is greater than that of a vertical pile under the same axial load, and bearing capacity of an inclined pile is smaller than that of a vertical pile. This is quite different from the case when the inclined pile is not affected by soil displacement. For inclined piles, P-Δ effect of axial load would lead to a large increase in bending moment, however, for the vertical pile, P-Δ effect of axial load can be neglected. Although the direction of inclination of piles is reverse, deformation of piles caused by uniform soil movement is totally the same. For the inclined piles discussed herein, bending moment(-8 m to-17 m under the ground) relies heavily on uniform soil movement and does not change during the process of applying axial load. When the thickness of soil is less than the pile length, the greater the thickness of soil, the larger the bending moment at lower part of the inclined pile. When the thickness of soil is larger than the pile length, bending moment at lower part of the inclined pile is zero.展开更多
文摘The numerical analysis on a shaft with rub-impact condition is done by using the finite difference method. The bending modes and the moment yaring along the shaft are described,to reveal the in crease pattern of sectional stress of the shaft. The result obtained in this paper can be used in explaining the phenomena of many breaking sections appeared in destructive failures of actual rotating machinery.
基金Project(10033135-2009-11) supported by the Korean Ministry of Knowledge Economy (MKE) through HNK. Co,Ltd.
文摘For the purpose of analyzing the torsional vibration caused by the gravitational unbalance torque arisen in a spindle system when it is machining heavy work piece,a 10-DOF lumped parameter model was made for the machine tool spindle system with geared transmission.By using the elementary method and Runge-Kutta method in Matlab,the eigenvalue problem was solved and the pure torsional vibration responses were obtained and examined.The results show that the spindle system cannot operate in the desired constant rotating speed as far as the gravitational unbalance torque is engaged,so it may cause bad effect on machining accuracy.And the torsional vibration increases infinitely near the resonant frequencies,so the spindle system cannot operate normally during these spindle speed ranges.
文摘In the framework of parallelism general relativity, the torsion axial-vector in the rotating gravitational field is studied in terms of the alternative Kerr tetrad. In thecase of the weak field and slow rotation approximation, we obtain that the torsion axial-vector possesses the dipole-like structure. Furthermore, the effect of massive neutrino spin precession in this field is mentioned.
文摘The paper presents the methodology and results of measurement designed to determine the effect of the rolling element separator （cage） at the frictional moment in ball bearings, The measurement was carried out on four groups on bearing with different cages. Measurements were carried out on torque-meter STPM, a device that has been designed and manufactured at Kielce University of Technology. The measurement results showed that the type of cage used in ball bearings has a significant impact on the frictional moment. In addition, the results also confirm that the size of the curvature ratio and the accuracy of the races shape have a significant impact on the frictional moment.
基金Project supported by the National Natural Science Foundation of China （Grant No 10473004）, the FADEDD （Grant No 200317）, and the SRFDP （Grant No 20040542003）.
文摘The massless scalar quasiaormal modes （QNMs） of a stationary axisymmetric Einstein-Maxwell dilato-axioa （EMDA） black hole are calculated numerically using the continued fraction method first proposed by Leaver. The fundamental quasinormal frequencies （slowly damped QNMs） are obtained and the peculiar behaviours of them are studied. It is shown that these frequencies depend on the dilaton parameter D, the rotational parameter a, the multiple moment l and the azimuthal number m, and have the same values with other authors at the Schwarzschild and Kerr limit.
基金Project(51208071)supported by the National Natural Science Foundation of ChinaProject(2010CB732106)supported by the National Basic Research Program of China
文摘The couple effect of soil displacement and axial load on the single inclined pile in cases of surcharge load and uniform soil movement is discussed in detail with the methods of full-scale field tests and finite element method. Parametric analyses including the degree of inclination and the distance between soil and pile are carried out herein. When the displacement of soil on the left side and right side of a pile is identical, deformation of a vertical pile and an inclined pile is highly close in both cases of surcharge load and uniform soil movement. When the couple effect of soil displacement and axial load occurs, settlement of an inclined pile is greater than that of a vertical pile under the same axial load, and bearing capacity of an inclined pile is smaller than that of a vertical pile. This is quite different from the case when the inclined pile is not affected by soil displacement. For inclined piles, P-Δ effect of axial load would lead to a large increase in bending moment, however, for the vertical pile, P-Δ effect of axial load can be neglected. Although the direction of inclination of piles is reverse, deformation of piles caused by uniform soil movement is totally the same. For the inclined piles discussed herein, bending moment(-8 m to-17 m under the ground) relies heavily on uniform soil movement and does not change during the process of applying axial load. When the thickness of soil is less than the pile length, the greater the thickness of soil, the larger the bending moment at lower part of the inclined pile. When the thickness of soil is larger than the pile length, bending moment at lower part of the inclined pile is zero.
