Mathematical And Experimental Investigation Of Vibration Isolation Characteristics Of Negative Stiffness System For Pipeline

Abstract

The technological advancement in both upstream and downstream industry has ensured safe handling and transfer of products (specially Oil, gas and petroleum) in both offshore and onshore part of business. The life cycle of pipeline depends on several negative parameters that caused by nature or system that where it is involved. Amidst all these life decaying factors, vibration is one of the significant reasons for which reliability and efficiency of pipeline and its associated equipment are being vulnerable day by day. Here in this dissertation, vibration in pipeline will be analyzed both in mathematically and experimentally before and after addition of negative stiffness system in the respective pipeline. After project phase accomplishment of a plant, the pipeline and its ancillary equipment (valves flange-flange joints, pneumatic and hydraulic parts, electrical cum instrumental devices), machineries (pump, compressor, motor), structures etc. remain safe and secure during operational handling of product if the negative factors specifically vibration is appropriately isolated or not. Vibration exerts a potential negative influence on both the transfer equipment and surrounding entities. The basic source of vibration is rotor. A multitude of various harmonics exist the vibration spectrum of actual product transfer unites and mainline pumps. During operations, region of resonance conditions constantly deviates, impact of vibration is observed highly significant during machineries are shut down and when it is started as well as hydrodynamic impact of mass flow through respective pipeline. The development of Negative Stiffness system for vibration isolation is therefore required to maintain safe and secure pipeline and its related units. This study involves construction of an experimental bench and pipeline with which to investigate systems with negative stiffness system as vibration isolators. The design, computer model, practically experimented data consists of elastic springs, serving as negative stiffness compensators. Normally the performance of conventional vibration isolation systems is specified by mounted stiffness required to support the weight of payload. Here the negative stiffness helps by resulting high static stiffness to support weight of payload and low dynamic stiffness to achieve significant vibration isolation bandwidth. This study exhibits the reduction of frequency and vibration of pipeline system by adding negative stiffness system with the main structure.