VIBRATION CONTROL OF PIPING SYSTEMS AND STRUCTURES USING TUNED MASS DAMPERS

Vibrations of piping systems and structures pose significant operational and commercial risks. Due to their inherently low mechanical damping, these systems exhibit resonance frequencies with high dynamic amplification factor. When subject to external forces from flow turbulences, pressure pulsation or mechanical equipment, these systems can respond with large amplitude vibration. Tuned mass dampers (TMD) provide effective means of controlling resonant vibration and offer two major advantages compared to other vibration control means: Firstly, the vibration reduction can be accurately predicted even if the forcing function remains unknown, leading to increased reliability of the proposed solution. Secondly, the need for hot work during installation can be avoided, resulting in reduced safety risks and less disruption to plant operations. Although TMDs are widely used in civil and mechanical engineering, they are not commonly considered when controlling vibrations in the piping industry. One reason for this may be the absence of industry design guidelines. This paper provides simple mathematical models for the design and analysis of TMDs using Microsoft Excel spreadsheet calculations. A method for the approximation of mechanical systems' dynamic behavior based on site measurements or finite element analyses is described, and practical guidance for the TMD design process provided. A series of examples shows how TMDs can be optimized to provide robust control of resonant vibrations.