experimental investigations on vibration response of misaligned rotors connected by flexible mechanical coupling with parallel and angular misalignment

Abstract

newline quotThe rotary machines utilize mechanical couplings between the drive and load. A common malfunction that happens is shaft misalignment. This happens when the load gets unbalanced during assembly or in course of operation. The reason could be incorrect machine assembly, thermal distortion or asymmetry in load. However, during assembly, care must be taken to keep it within a tolerable limit. The alignment condition of the machines varies because of the asymmetry in loads, thermal distortion, unequal foundation settlement, and various other static loadings. It leads to the development of reactive forces in the coupling and is often a major cause of vibration and brings to poor efficiency of the rotating machines, which in turn culminates in failure. It will be helpful during diagnosis to have a meticulous study of the vibration characteristics on misalignments newline newlineTo study the dynamics of misaligned rotors, a setup is modelled and constructed. The setup is modelled to replicate a bigger rotor dynamics machine and fabricated for experimentation in the laboratory. Investigation is carried out to study the effect of provoked misalignments between the rotors using flexible couplings that are used in high precision CNC and automated machines. newline newlineThe present research also carries a steady-state vibration reaction on an integer fraction of the initial bending Natural Frequency (NF). The first four fundamental natural frequencies are calculated using MATLAB code and the conventional energy method for the misaligned rotor. Additionally, the effects of Parallel Misalignments (PM), Angular Misalignments (AM) and a combination of AM and PM are analyzed.In this work, the effects of complex alignment are studied through the well-balanced designed test rig in two perpendicular planes. The test rig is ensured at a bare minimum level of vibration by taking care of fabrication and assembly. A programmable Variable Frequency Drive (VFD) is used to control the speed of the rig. The test rig facilitates easy axis shifting