Vibration problem of rotating machineries at high rpm

Abstract

High speed machining is evident today. The need to go faster is critical in saving time, as well as ensuring quality and accuracy. Air bearings have been integrated into high speed drilling and milling machines. Determining maximum rotational speeds that the rotor can withstand without going to resonance is still unknown. Predicting the maximum speed without the actual occurrence of vibration is needed.

In this report, a testing apparatus, which has some resemblance to rotor housing, is designed and fabricated for analysis of change in height due to addition of weight. Firstly, extensive literature review was conducted to understand the behaviour of air bearings in a rotor system. Secondly, conceptual designs for a test rig were generated before the final design was chosen and fabricated. Extensive trial and analysis were conducted to consolidate useful data. Finally, analytical calculations were performed with equations found from books and research papers with the intention to predict bearing stiffness mathematically. The success of formulating an equation is discussed at the end of this report.