Experimental identification of the vibration modes of liquid‐filled conical tanks and validation of a numerical model

Abstract

SUMMARYTruncated conical-shaped shells are widely used as containment vessels in elevated water tanks. In the aftermath of earthquakes, water tanks play a vital role in supplying the water needed for extinguishing ÿres that usually occur during these catastrophic events. As such, special attention has to be given when designing water tanks in order to assure safety and functionality of these structures during a seismic event. To the best of the authors' knowledge, this paper reports the ÿrst experimental program conducted to evaluate the dynamic characteristics of liquid-ÿlled exible conical shell structures. A small-scale aluminium conical shell model was mounted to a shaking table and subjected to a set of dynamic excitations. In the ÿrst phase of the experimental program, acceleration measurements were used to identify the ÿrst two modes of vibration. In the second experimental phase, the cos(Â)-modes were identiÿed through base shear and overturning moment measurements. The study was also conducted analytically using a numerical model that was previously developed by El Damatty et al. The model accounts for the e ect of the added mass resulting from the developed hydrodynamic pressure through a proper uid-structure interaction formulation. Tests conducted in the two experimental phases were simulated using this numerical model. In general, the experimental and analytical predictions of the dynamic characteristics of the tested model were in very good agreement. This provides a validation of the previously developed numerical model. The analytical model was then implemented to assess the generalized added mass of the contained uid.

Seismic Response of Ground Cylindrical and Elevated Conical Reinforced Concrete Tanks

“…The shell vibration was determined assuming zero hydrodynamic pressure at the liquid free-surface. The validity of this analytical model was verified in a later experimental study carried out by Sweedan and El Damatty (2002) on a small-scale purely conical tank.…”

Non-Contact Water Level Response Measurement of a Tubular Level Gauge Using Image Signals

“…The coordinates with the maximum value represent the displacement of the object caused by an external force. In Equations (1) and (2), f (x i , y j ) and g(x i , y j ) represent the gray level values of the windows before and after deformation, respectively.…”

“…Thus, to evaluate the safety of liquid storage tanks, it is important to identify their dynamic characteristics. Many studies have been conducted to identify the dynamic characteristics of liquid storage tanks, and it was found that their dynamic characteristics are affected by their geometry and materials, the types of fluids stored in them, their water level, and the excitation force applied on them [2][3][4][5]. When dynamic loads such as earthquakes are applied to a liquid storage tank, the hydrodynamic pressure acting on the structure and the dynamic behavior of the structure can be significantly amplified due to the interaction between the structure and the liquid inside it.…”

Active vibration control of conical shells using piezoelectric materials

“…Although the active vibration control of beams, plates and cylindrical shells has received many people's attention, to our knowledge, few people have studied the active vibration control of conical shells. Conical shells are widely used as important structural components in many engineering fields Liew, 1995, 1996;Sweedan and El Damatty, 2003;Senthil Kumar and Ganesan, 2008;Kayran and Yavuzbalkan, 2009;Sofiyev, 2009;Tornabene, 2009;Kerboua et al, 2010). Normally, the equation of motion of the conical shell is very complicated and some coefficients of the equation of motion are variables (Lam and Li, 1999b), which makes it difficult to analytically solve the equation of motion of the conical shell.…”