Torsional vibrations occur when a rotating shaft or other component in a machine experiences a twisting and oscillating movement. While this phenomenon can be beneficial for certain applications, it can become dangerous and costly if it is not properly managed. Couplings are one of the most vulnerable components of a machine, and excessive torsional vibration can lead to severe failures of such items as shafts, fans, gears, engine dampers, and compressor oil pumps, all of which can be expensive to replace or repair. In this blog post, we will discuss how to prevent costly torsional vibrations. We will examine the various factors that contribute to torsional vibration and explore how to manage them through preventive maintenance, the selection and application of appropriate dampers, and the use of proper balancing techniques. We will also take a look at the common methods used to measure and monitor torsional vibration in machinery.
Torsional vibration is an angular vibration of an object, usually a shaft, along its axis of rotation. It can cause a variety of problems such as flexible coupling wear, gear wear, and vibrations traveling to various areas of the hull structure. It can lead to failures of shafts, couplings, fans, gears, engine dampers, and oil pumps. To prevent torsional vibration, the frequency and amplitude of the oscillations must be accounted for by properly designing the torsional stiffness of the system. This can be done by involving the mass and stiffness of the rotating components, the expected harmonics and speeds, and the torques and damping that are present in the system. Proper fitting of couplings should also be ensured to avoid sharp corners and excessive torque causing torsion overload. Variable frequency drives, when used to control motors, can also create torsional excitation which can lead to fatigue failures. Proper control and monitoring of torsional vibration is essential to prevent costly failures and extend the longevity of shafts, couplings, and other components.
Detecting torsional vibration is essential in order to prevent expensive failures. This requires close monitoring using vibration analysis, speed, torque, and vibration of the shafts and other components. By utilizing vibration sensors and dynamometer tests, costly torsional vibration failures can be prevented.
Various methods exist for preventing torsional vibrations and ensuring the equipment remains intact. The most commonly used methods are dampers, which optimize the natural frequency of a system to significantly reduce critical resonances. Dampers work by absorbing and dissipating torsional vibrations through the use of a spring and damping element. Additionally, lubrication in the form of oil or grease can be applied to the system to reduce friction and the amplitude of the vibration by dissipating energy. Improved coupling materials also serve to reduce the amplitude of torsional vibrations. If these materials are used, they should be checked regularly as they may degrade over time.
To prevent costly repairs, It’s essential to have a process in place for routinely monitoring torsional vibrations and to use the proper materials and methods.