Vibration it can be very harmful – leading to eventual failure of the system. Consequently, one of the major reasons for vibration analysis is to predict when this type of resonance may occur and then to determine what steps to take to prevent it from occurring. As the amplitude plot shows, adding damping can significantly reduce the magnitude of the vibration. Also, the magnitude can be reduced if the natural frequency can be shifted away from the forcing frequency by changing the stiffness or mass of the system. If the system cannot be changed, perhaps the forcing frequency can be shifted
Pound per hour Pound per hour Pound per hour is a mass flow unit. It is abbreviated as PPH or more conventionally as lb/h. Fuel flow for engines is usually expressed using this unit. It is particularly useful when dealing with gases or liquids, as volume flow varies more with temperature and pressure. In the US utility industry, steam and water flows throughout turbine cycles are typically expressed in PPH, while in Europe these mass flows are usually expressed in metric tonnes per hour: Minimum fuel intake on a jumbo jet can be as low as 150 lb/h when idling; however, this is