This paper puts forward the concept of double semi-active vibration isolation systemutilizing the 'on-off' active damper and the 'on-off' active spring. Applying KBM Asympto-tic method, the vibration ...This paper puts forward the concept of double semi-active vibration isolation systemutilizing the 'on-off' active damper and the 'on-off' active spring. Applying KBM Asympto-tic method, the vibration of the system in case of weak semi-active control is studied. ln pcactice, there are two types of vibration isolation. One is to isolate the transmitting of the cyclicunbalanced force generated by the revolving machine to the surroundings. The other is to isolatethe transmitting of the vibration displacement of the surroundings to precise equipment. Deduc-ing the influence of the roadway unflatness on vehicles also belongs to this type. For the firsttype of isolation system, the damper always dissipates energy, and the total work done by the spring in a vibration cycle is zero. For the second type of isolation system, the work done by the damper sometimes is positive, and sometimes negative. The damper dissipates less energy. The work done by the spring in a vibration cycle isn't zero, and it is usually positive. ln thispaper, the vibration isolation is refered to the second type. .展开更多
In this study, the effects of mechanical vibration on the mechanical properties of ceramic diesel particulate filters(DPFs) were investigated. The goal is to determine how the mechanical vibration used in the regenera...In this study, the effects of mechanical vibration on the mechanical properties of ceramic diesel particulate filters(DPFs) were investigated. The goal is to determine how the mechanical vibration used in the regenerative ash cleaning process for these filters affects their mechanical integrity during subsequent reuse. Both virgin and vibrated DPF samples were subjected to compressive and 3-point flexural loading at three different loading rates along axial and tangential directions. Statistical analysis was conducted to determine the significance of variation in the compressive and flexural strengths of the DPFs as a result of exposure to mechanical vibration. The results show that there is no statistically significant difference in both compressive and flexural strengths of the virgin DPFs and the DPFs subjected to the same level of mechanical vibration typically used in ash cleaning of DPFs. When the intensity of vibration was doubled, the drop in compressive strength became statistically significant, but less than 10% under axial loading. However, no drop in flexural strength was observed for DPFs subjected to this high intensity of mechanical vibration. The safe threshold for mechanical vibration of ceramic filters is considered to be much higher than that currently used in vibration-based ash cleaning process.展开更多
文摘This paper puts forward the concept of double semi-active vibration isolation systemutilizing the 'on-off' active damper and the 'on-off' active spring. Applying KBM Asympto-tic method, the vibration of the system in case of weak semi-active control is studied. ln pcactice, there are two types of vibration isolation. One is to isolate the transmitting of the cyclicunbalanced force generated by the revolving machine to the surroundings. The other is to isolatethe transmitting of the vibration displacement of the surroundings to precise equipment. Deduc-ing the influence of the roadway unflatness on vehicles also belongs to this type. For the firsttype of isolation system, the damper always dissipates energy, and the total work done by the spring in a vibration cycle is zero. For the second type of isolation system, the work done by the damper sometimes is positive, and sometimes negative. The damper dissipates less energy. The work done by the spring in a vibration cycle isn't zero, and it is usually positive. ln thispaper, the vibration isolation is refered to the second type. .
基金supported by the National Science Foundation under Grant No.1230444
文摘In this study, the effects of mechanical vibration on the mechanical properties of ceramic diesel particulate filters(DPFs) were investigated. The goal is to determine how the mechanical vibration used in the regenerative ash cleaning process for these filters affects their mechanical integrity during subsequent reuse. Both virgin and vibrated DPF samples were subjected to compressive and 3-point flexural loading at three different loading rates along axial and tangential directions. Statistical analysis was conducted to determine the significance of variation in the compressive and flexural strengths of the DPFs as a result of exposure to mechanical vibration. The results show that there is no statistically significant difference in both compressive and flexural strengths of the virgin DPFs and the DPFs subjected to the same level of mechanical vibration typically used in ash cleaning of DPFs. When the intensity of vibration was doubled, the drop in compressive strength became statistically significant, but less than 10% under axial loading. However, no drop in flexural strength was observed for DPFs subjected to this high intensity of mechanical vibration. The safe threshold for mechanical vibration of ceramic filters is considered to be much higher than that currently used in vibration-based ash cleaning process.
