In order to improve the starved lubrication condition of rolling bearings,three kinds of textures,namely dimple,groove texture,and gradient groove texture,were developed on the guiding surface of thrust ball bearings ...In order to improve the starved lubrication condition of rolling bearings,three kinds of textures,namely dimple,groove texture,and gradient groove texture,were developed on the guiding surface of thrust ball bearings in this study.The results show that gradient groove texture has the one-way self-driving function of liquid droplets.The root mean square(RMS)value of vibration acceleration of gradient groove textured bearing(GGB)decreased by 49.1% and the kurtosis decreased by 24.6% compared with non-textured bearing(NB)due to the directional spreading effect of gradient groove textures on oil.The frequency domain analysis showed that the textures mainly suppressed the medium and high-frequency energy of bearing vibration,and the GGB was reduced the most with 65.3% and 48%,respectively.In addition,whether the grease is sufficiently sheared has a large impact on the oil guiding effect,and the friction torque of GGB could decrease by 10.5% compared with NB in the sufficiently sheared condition.Therefore,the gradient groove texture with oil self-driven effect on the guiding surface of rolling bearing can effectively improve the lubrication condition of the bearing and thus reduce the bearing vibration and friction torque,which has a promising application prospect.展开更多
This paper presents a novel stochastic collocation method based on the equivalent weak form of multivariate function integral to quantify and manage uncertainties in complex mechanical systems. The proposed method, wh...This paper presents a novel stochastic collocation method based on the equivalent weak form of multivariate function integral to quantify and manage uncertainties in complex mechanical systems. The proposed method, which combines the advantages of the response surface method and the traditional stochastic collocation method, only sets integral points at the guide lines of the response surface. The statistics, in an engineering problem with many uncertain parameters, are then transformed into a linear combination of simple functions' statistics. Furthermore, the issue of determining a simple method to solve the weight-factor sets is discussed in detail. The weight-factor sets of two commonly used probabilistic distribution types are given in table form. Studies on the computational accuracy and efforts show that a good balance in computer capacity is achieved at present. It should be noted that it's a non-gradient and non-intrusive algorithm with strong portability. For the sake of validating the procedure, three numerical examples concerning a mathematical function with analytical expression, structural design of a straight wing, and flutter analysis of a composite wing are used to show the effectiveness of the guided stochastic collocation method.展开更多
基金supported by National Key R&D Program of China(Grant No.2020YFB2006803)the Fundamental Research Funds for the Provincial Universities of Zhejiang(Grant No.GK209907299001-006)+1 种基金Natural Science Foundation of Zhejiang Province(Grant No.LY19E050014)Foundation of Zhejiang Provincial Education Department of China(Grant No.Y202044314).
文摘In order to improve the starved lubrication condition of rolling bearings,three kinds of textures,namely dimple,groove texture,and gradient groove texture,were developed on the guiding surface of thrust ball bearings in this study.The results show that gradient groove texture has the one-way self-driving function of liquid droplets.The root mean square(RMS)value of vibration acceleration of gradient groove textured bearing(GGB)decreased by 49.1% and the kurtosis decreased by 24.6% compared with non-textured bearing(NB)due to the directional spreading effect of gradient groove textures on oil.The frequency domain analysis showed that the textures mainly suppressed the medium and high-frequency energy of bearing vibration,and the GGB was reduced the most with 65.3% and 48%,respectively.In addition,whether the grease is sufficiently sheared has a large impact on the oil guiding effect,and the friction torque of GGB could decrease by 10.5% compared with NB in the sufficiently sheared condition.Therefore,the gradient groove texture with oil self-driven effect on the guiding surface of rolling bearing can effectively improve the lubrication condition of the bearing and thus reduce the bearing vibration and friction torque,which has a promising application prospect.
基金supported by the Defense Industrial Technology Development Program(Grant Nos.A2120110001 and B2120110011)the National Natural Science Foundation of China(Grant No.A020317)
文摘This paper presents a novel stochastic collocation method based on the equivalent weak form of multivariate function integral to quantify and manage uncertainties in complex mechanical systems. The proposed method, which combines the advantages of the response surface method and the traditional stochastic collocation method, only sets integral points at the guide lines of the response surface. The statistics, in an engineering problem with many uncertain parameters, are then transformed into a linear combination of simple functions' statistics. Furthermore, the issue of determining a simple method to solve the weight-factor sets is discussed in detail. The weight-factor sets of two commonly used probabilistic distribution types are given in table form. Studies on the computational accuracy and efforts show that a good balance in computer capacity is achieved at present. It should be noted that it's a non-gradient and non-intrusive algorithm with strong portability. For the sake of validating the procedure, three numerical examples concerning a mathematical function with analytical expression, structural design of a straight wing, and flutter analysis of a composite wing are used to show the effectiveness of the guided stochastic collocation method.
