Active Vibration Control Analysis of Storage Tank by Using Smart Material

Abstract

Storage tank is the most important equipment in oil industries. The main parts of floating storage tank are shell plate, bottom plate and floating roof plate. Storage tank especially with floating roof affected by undesired vibrations which generated by wind force and earthquakes force. The shell of tank exposed to these vibrations despite of there is wind girder and as a result simple slant or buckling occurs on the shell over time. This simple slant or buckling on the shell of tank prevented the floating roof from moving up and down and then storage tank will become out of order unless will do reconstruction for it with extremely high cost. This problem is the topic of this research and happened at many projects in south of Iraq. Smart storage tank is the solution to this problem. Active vibration control (AVC) cancelled all vibrations which caused instability to the storage tank. Storage tank embeds by Piezoelectric (smart material) to make AVC for it that contained of sensor and actuator. Smart material gives extremely big force in short time and hence quick response rate. Output feedback control is one of the methods for AVC that used in this research. ANSYS parametric design language (APDL) employ to obtain numerically modelled for storage tank due to complex structure and require to get couple filed analyses (displacement for tank and voltage for Piezoelectric). Output feedback control has been represented by finite element method. The load of wind or earthquakes forces applied to tank by sin wave (harmonic excitation) piezoelectric shaker. AVC achieved by selected the best of actuation voltages and the best of control gains and as the result the amplitude of displacement without control is ± 0.015m and with control is ± 0.0006m.

Keywords: Smart material, Storage Tank, Active vibration control.