Solving Structural Vibration Problems Using Operating Deflection Shape (ODS) And FEA: Part I & Part II

Abstract

This tutorial focuses on vibration issues in pumps primarily for power plants, refineries, and municipal water and waste water treatment plants. Over the years, the original equipment manufacturer (OEM) and the end user often have been able to solve vibration problems for this kind of equipment based on their experience. An adequate maintenance program can identify and solve typical vibration responses and 1x and 2x running speed due to imbalance or misalignment. However,when the vibration is due to a resonance of structural natural frequency or an unexpected geometry change such as looseness or cracking, it becomes more complicated. The trial and error approach can be time consuming and is considered the least cost effective method to solve this type of problem. Therefore, thorough vibration testing combined with detailed calibrated finite element analysis (FEA) models have become powerful tools to identify and mitigate vibration issues through will-conceived fixes while reducing the risk of introducing new ones. This tutorial will provide and in-depth look at how the combination of field testing and computer analysis can solve vibration issues in a timely and cost-effective manner. Several case studies will be presented that demonstrate this method.