The influence of the flexible body for the motion of gear transmission system is analyzed and the foundation for a more accurate assessment of gear transmission system is established when it has battle damage faults. ...The influence of the flexible body for the motion of gear transmission system is analyzed and the foundation for a more accurate assessment of gear transmission system is established when it has battle damage faults. By using Pro / E software,the virtual prototype model of gear transmission system in the speed reducer is established,and the rigid model and rigid-flexible coupling model are simulated respectively in ADAMS to obtain the data of gear meshing force. It can be concluded that rigid-flexible coupling model can reflect the real motion better than rigid model by comparing the simulation data of two models.展开更多
A trunk-vibrating screen is widely used in olive harvesting machinery.Because of the irregularity of fruit recovery efficiency,the recovery efficiency fluctuates greatly.Vibration harvesting parameters are important f...A trunk-vibrating screen is widely used in olive harvesting machinery.Because of the irregularity of fruit recovery efficiency,the recovery efficiency fluctuates greatly.Vibration harvesting parameters are important factors affecting the percentage of olive harvest.Therefore,the study of vibration picking parameters is of great significance for olive harvest.Vibration parameters,governed by tree morphological parameters,strongly influence the efficiency of vibration harvesting.In this study,a combination of response surface simulation and harvesting experiments was used to investigate the relationship between morphological and vibration harvesting parameters in“three open-center shape”olive trees.First,force analysis and experimental measurements were performed on the olive fruit,and the Box-Behnken design was used to obtain the vibration parameters through finite element simulation and to establish the response surface model of the parameters(main trunk diameter,main trunk height,main branch angles A and B)and the vibration parameters(vibration frequency and vibration force)of the“three open-center-shape”olive trees.In addition,the mapping relationship between tree shape parameters and vibration parameters was obtained.The results show that the 90%quantile of the acceleration of abscission of olives is 1113.35 m/s2;the average correlation coefficient between the simulation and the experiment results was 0.73,and the simulation was a good representation of the experimental results.When the tree shape was“three open-center”,the trunk diameter and height were related to the vibration harvesting parameters;the average harvesting efficiency of olives was 91.22%,and the resonance frequency of the monitoring points was similar to that of the simulation results.This study provides a reference for the design of vibration harvesting equipment and fruit tree shaping.展开更多
A complete geometric nonlinear formulation for rigid-flexible coupling dynamics of a flexible beam undergoing large overall motion was proposed based on virtual work principle, in which all the high-order terms relate...A complete geometric nonlinear formulation for rigid-flexible coupling dynamics of a flexible beam undergoing large overall motion was proposed based on virtual work principle, in which all the high-order terms related to coupling deformation were included in dynamic equations. Simulation examples of the flexible beam with prescribed rotation and free rotation were investigated. Numerical results show that the use of the first-order approximation coupling (FOAC) model may lead to a significant error when the flexible beam experiences large deformation or large deformation velocity. However, the correct solutions can always be obtained by using the present complete model. The difference in essence between this model and the FOAC model is revealed. These coupling high-order terms, which are ignored in FOAC model, have a remarkable effect on the dynamic behavior of the flexible body. Therefore, these terms should be included for the rigid-flexible dynamic modeling and analysis of flexible body undergoing motions with high speed.展开更多
文摘The influence of the flexible body for the motion of gear transmission system is analyzed and the foundation for a more accurate assessment of gear transmission system is established when it has battle damage faults. By using Pro / E software,the virtual prototype model of gear transmission system in the speed reducer is established,and the rigid model and rigid-flexible coupling model are simulated respectively in ADAMS to obtain the data of gear meshing force. It can be concluded that rigid-flexible coupling model can reflect the real motion better than rigid model by comparing the simulation data of two models.
基金supported by the Key Research and Development Plan of Shaanxi Province(Grant No.2024NCZDCYL-05-03)the Key Programs of the Joint Fund of the National Natural Science Foundation of China(Grant No.U2243235)the Introduction of High-level Talents in Hohhot(Grant No.2023RC-High Level-7).
文摘A trunk-vibrating screen is widely used in olive harvesting machinery.Because of the irregularity of fruit recovery efficiency,the recovery efficiency fluctuates greatly.Vibration harvesting parameters are important factors affecting the percentage of olive harvest.Therefore,the study of vibration picking parameters is of great significance for olive harvest.Vibration parameters,governed by tree morphological parameters,strongly influence the efficiency of vibration harvesting.In this study,a combination of response surface simulation and harvesting experiments was used to investigate the relationship between morphological and vibration harvesting parameters in“three open-center shape”olive trees.First,force analysis and experimental measurements were performed on the olive fruit,and the Box-Behnken design was used to obtain the vibration parameters through finite element simulation and to establish the response surface model of the parameters(main trunk diameter,main trunk height,main branch angles A and B)and the vibration parameters(vibration frequency and vibration force)of the“three open-center-shape”olive trees.In addition,the mapping relationship between tree shape parameters and vibration parameters was obtained.The results show that the 90%quantile of the acceleration of abscission of olives is 1113.35 m/s2;the average correlation coefficient between the simulation and the experiment results was 0.73,and the simulation was a good representation of the experimental results.When the tree shape was“three open-center”,the trunk diameter and height were related to the vibration harvesting parameters;the average harvesting efficiency of olives was 91.22%,and the resonance frequency of the monitoring points was similar to that of the simulation results.This study provides a reference for the design of vibration harvesting equipment and fruit tree shaping.
基金Project(10772113) supported by the National Natural Science Foundation of China
文摘A complete geometric nonlinear formulation for rigid-flexible coupling dynamics of a flexible beam undergoing large overall motion was proposed based on virtual work principle, in which all the high-order terms related to coupling deformation were included in dynamic equations. Simulation examples of the flexible beam with prescribed rotation and free rotation were investigated. Numerical results show that the use of the first-order approximation coupling (FOAC) model may lead to a significant error when the flexible beam experiences large deformation or large deformation velocity. However, the correct solutions can always be obtained by using the present complete model. The difference in essence between this model and the FOAC model is revealed. These coupling high-order terms, which are ignored in FOAC model, have a remarkable effect on the dynamic behavior of the flexible body. Therefore, these terms should be included for the rigid-flexible dynamic modeling and analysis of flexible body undergoing motions with high speed.
