学习计划1444819.doc

Research Proposal for ****** Title of research Identification and vibration reduction of anisotropic rotors Aim of research The research project covers the analysis of vibration phenomena and their compensation which arise for anisotropic rotors. The focus lies on the identification of the bending stiffness anisotropy in size and direction estimated from measured vibration signals. Based on this identification, targeted countermeasures can be developed like subsequent machining or active compensation. Background and motivation The requirements on efficiency and precision of rotary machines rise consistently. This performance improvement is achieved by increasing the revolution speed leading to vibration issues that needs to be solved. In this consistent process vibration problems become important that played a minor role a few years ago. An example is the roll in paper production that is driven at higher operational speed and redesigned with an increased rotor length. Such a roll is driven in subcritical operation. However, the range of operational speeds reaches significantly over the half of the first lateral critical speed. In the vicinity of the half of this critical speed often resonant vibrations occur with a major frequency component at double the rotor speed [1]. This resonance is known as the weight critical of anisotropic rotors [2,3]. Thereby the rolls are geometrically round down to manufacturing precision but their bending stiffness is distributed anisotropically along the rotor axis. This anisotropy may be a result of a non-symmetrically distributed microstructure of the underlying material in a cross-section due to an irregular cooling down during casting or different wall thicknesses of tube-like rotors along the rotor axis. These production defects are difficult, if possible, to avoid. The resulting resonant vibrations can only be mitigated by reducing the stiffness anisotropy itself. Therefore, the identification and compensation of the anisotropy