Chatter vibration is a major obstacle inachieveing increased machining performance. In thisresearch, a finite element model of chip formation in a 2Dmilling process is used to predict the occurrence of chattervibratio...Chatter vibration is a major obstacle inachieveing increased machining performance. In thisresearch, a finite element model of chip formation in a 2Dmilling process is used to predict the occurrence of chattervibrations, and to investigate the effects of variousmachining parameters on this phenomenon. The dynamicproperties of the machine tool at the tool tip are obtainedbased on experimental modal analysis, and are used in themodel as the cutter dynamics. The model allows for thenatural development of vibration as the result of the chip-tool engagement, and accounts for various phenomena thatoccur at the chip-tool interface ultimately leading tostable or unstable cutting. The model was used todemonstrate the effects of the machining parameters, suchas the axial depth of cut, radial immersion, and feed rate,on the occurrence of chatter. Additionally, the phenomenonof jumping out of the cut region could be observed in thismodel and its effect on the chatter process is demonstrated.The numerical model is verified based on comparisons withexperimental results.展开更多
In this work, the stability of a flexible thin cylindrical workpiece in turning is analyzed. A process model is derived based on a finite element representation of the workpiece flexibility and a nonlinear cutting for...In this work, the stability of a flexible thin cylindrical workpiece in turning is analyzed. A process model is derived based on a finite element representation of the workpiece flexibility and a nonlinear cutting force law. Repeated cutting of the same surface due to overlapping cuts is modeled with the help of a time delay. The stability of the so obtained system of periodic delay differential equations is then determined using an approximation as a time-discrete system and Floquet theory. The time-discrete system is obtained using the semi-discretization method. The method is implemented to analyze the stability of two different workpiece models of different thicknesses for different tool positions with respect to the jaw end. It is shown that the stability chart depends on the tool position as well as on the thickness.展开更多
文摘Chatter vibration is a major obstacle inachieveing increased machining performance. In thisresearch, a finite element model of chip formation in a 2Dmilling process is used to predict the occurrence of chattervibrations, and to investigate the effects of variousmachining parameters on this phenomenon. The dynamicproperties of the machine tool at the tool tip are obtainedbased on experimental modal analysis, and are used in themodel as the cutter dynamics. The model allows for thenatural development of vibration as the result of the chip-tool engagement, and accounts for various phenomena thatoccur at the chip-tool interface ultimately leading tostable or unstable cutting. The model was used todemonstrate the effects of the machining parameters, suchas the axial depth of cut, radial immersion, and feed rate,on the occurrence of chatter. Additionally, the phenomenonof jumping out of the cut region could be observed in thismodel and its effect on the chatter process is demonstrated.The numerical model is verified based on comparisons withexperimental results.
基金partially done while Arnab Chanda visited the University of Stuttgart from September 2010 to May 2011 under DAAD-IIT Sandwich Master Program funded by a DAAD M.Sc.ScholarshipThe doctoral research of Achim Fischer was funded since 2010 by the Baden-Wrttemberg Stiftung and the Stuttgart Cluster of Excellence Simtech
文摘In this work, the stability of a flexible thin cylindrical workpiece in turning is analyzed. A process model is derived based on a finite element representation of the workpiece flexibility and a nonlinear cutting force law. Repeated cutting of the same surface due to overlapping cuts is modeled with the help of a time delay. The stability of the so obtained system of periodic delay differential equations is then determined using an approximation as a time-discrete system and Floquet theory. The time-discrete system is obtained using the semi-discretization method. The method is implemented to analyze the stability of two different workpiece models of different thicknesses for different tool positions with respect to the jaw end. It is shown that the stability chart depends on the tool position as well as on the thickness.
