Active vibration control of vortex induced vibration on segmented cylindrical marine riser model

Mohammed, Mohammed Jawad

Active vibration control of vortex induced vibration on segmented cylindrical marine riser model

dc.contributor.author	Mohammed, Mohammed Jawad
dc.date.accessioned	2024-11-28T00:34:18Z
dc.date.available	2024-11-28T00:34:18Z
dc.date.issued	2016
dc.description	Thesis (Ph.D (Mechanical Engineering))
dc.description.abstract	The interaction between the bluff structures and the fluid flowing in perpendicular direction that leads the body to vibrate in cross-flow is called vortex induced vibration (VIV) that considers the main factor lead to the structure failure. Two suppression control strategies have been studied which are; passive control that depends on increasing the stiffness or mass without using external power and active control that depends on employing the sensors and actuators with feedback system to cancel the effect of VIV on the structure. In this research, an experimental setup of segmented cylindrical marine riser model caused by VIV is designed, developed and fabricated as a platform for the active controller development and verification. The experimental rig is used to collect the flow speed as input data and cylinder vibration amplitude as output data. Nonlinear system identification (SI) techniques were employed to model the nonlinear dynamic behavior of the cylindrical structure subjected to VIV which are; neural network based on nonlinear auto-regressive external (exogenous) input (NN-NARX), nonlinear auto-regressive (NN-NAR), nonlinear input-output (NN-NIO) models and adaptive neuro-fuzzy inference system (ANFIS) which were employed using superior NN-NARX model due to lowest mean square prediction error (MSE) of 1.1041×10-6. Next, PID based controllers tuned by heuristic method, particle swarm optimization (PSO) and iterative learning algorithm (ILA) were developed to control the unwanted vibration. In addition, Fuzzy-PID (FPID) controller was also developed as an intelligent controller. Based on the simulation results, PID-PSO has recorded the lowest MSE of 9.2659×10-5 reduction of 79.75 % as compared to the other controllers. For experimental validation, passive control is implemented to see the effect of double control rods at two locations on the cylinder and the results revealed that the cylinder remains vibrated for both of cases. Thus, active open and close loops vibration controls have been implemented to reduce the marine riser deflection via double control rods driven by double motors 12 V. Initially, an active open loop control technique was applied via proposed motors based on the rotational direction clockwise CW and counter clockwise CCW. Then, four voltages (6 V, 8 V, 10 V and 12 V) are supplied to the electromechanical motors to derive double control rods in the best direction (CCW). Finally, an active close loop control verified by the best optimized controllers PID-PSO, PID-ILA and FPID based on simulation results are employed to attenuate the undesired vibration via control rods in two positions driven by electromechanical motors. As a result, all types of controllers were able to suppress the vibration. However, PID-PSO controller is more superior as compared to the other approaches with vibration suppression of 66% on the vibrating marine riser
dc.description.sponsorship	Faculty of Mechanical Engineering
dc.identifier.uri	https://openscience.utm.my/handle/123456789/1368
dc.language.iso	en
dc.publisher	Universiti Teknologi Malaysia
dc.subject	Vortex-motion
dc.subject	Offshore structures—Vibration
dc.title	Active vibration control of vortex induced vibration on segmented cylindrical marine riser model
dc.type	Thesis
dc.type	Dataset