Conception of a 3D Metamaterial-Based Foundation for Static and Seismic Protection of Fuel Storage Tanks

Abstract

Fluid-filled tanks in tank farms of industrial plants can experience severe damage and trigger cascading effects in neighboring tanks due to large vibrations induced by strong earthquakes. In order to reduce these tank vibrations, we have explored an innovative type of foundation based on metamaterial concepts. Metamaterials are generally regarded as manmade structures that exhibit unusual responses not readily observed in natural materials. If properly designed, they are able to stop or attenuate wave propagation. Recent studies have shown that if locally resonant structures are periodically placed in a matrix material, the resulting metamaterial forms a phononic lattice that creates a stop band able to forbid elastic wave propagation within a selected band gap frequency range. Conventional phononic lattice structures need huge unit cells for low-frequency vibration shielding, while locally resonant metamaterials can rely on lattice constants much smaller than the longitudinal wavelengths of propagating waves. Along this line, we have investigated 3D structured foundations with effective attenuation zones conceived as vibration isolation systems for storage tanks. In particular, the three-component periodic foundation cell has been developed using two common construction materials, namely concrete and rubber. Relevant frequency band gaps, computed using the Floquet-Bloch theorem, have been found to be wide and in the low-frequency region. Based on the designed unit cell, a finite foundation has been conceived, checked under static loads and numerically tested on its wave attenuation properties. Then, by means of a parametric study we found a favorable correlation between the shear stiffness of foundation walls and wave attenuation. On this basis, to show the potential improvements of this foundation, we investigated an optimized design by means of analytical models and numerical analyses. In addition, we investigated the influence of cracks in the matrix material on the elastic wave propagation, and by comparing the dispersion curves of the cracked and uncracked materials we found that small cracks have a negligible influence on dispersive properties. Finally, harmonic analysis results displayed that the conceived smart foundations can effectively isolate storage tanks.

Finite locally resonant Metafoundations for the seismic protection of fuel storage tanks

“…This particular property has opened an innovative direction to reduce earthquake-induced vibrations. [10][11][12] At the outset, two types of applications have been proposed based on this phenomenon: (1) foundations with embedded resonators [13][14][15][16] capable of attenuating seismic waves effects and (2) barriers that are able to redirect surface waves back into the ground. [17][18][19][20] More precisely, Cheng and Shi 14 studied a periodic foundation composed of a reinforced concrete matrix and steel masses that are connected to the matrix with rubber layers.…”

“…This particular property has opened an innovative direction to reduce earthquake‐induced vibrations . At the outset, two types of applications have been proposed based on this phenomenon: (1) foundations with embedded resonators capable of attenuating seismic waves effects and (2) barriers that are able to redirect surface waves back into the ground …”

On the Use of Meta-Foundations for Seismic Isolation: A Practical Application for Conventional Buildings

“…The potential advantage of metafoundations against conventional base isolation is in reducing the large displacement demand by reflecting the incoming energy on the interfaces and/or by dissipating energy through local resonance. Since the pioneering works on phononic crystals and metamaterials [7,8,9], a lot of recent interesting studies in the framework of metafoundations have been published [5,6,10,11,12,13,14,15,16]. The crucial challenge is the realisation of a sufficient band gap, targeting the main frequency content of the earthquake excitation and the characteristic frequencies of the isolated structure (normally between 0.5-10 Hz), while maintaining the dimensions of the foundation in a realistic range.…”

On the Geometrically Nonlinear Elastic Response of Class θ = 1 Tensegrity Prisms

“…The study of band gaps in tensegrity-based metamaterials, and their tuning for the design and test of novel waveguides, sound proof layers, and/or vibration protection devices deserves special attention (Theocharis et al, 2013). Other innovative uses of lattice metamaterials can be found in Amendola et al (2017), Colombi et al (2017), Feo et al (2017), Genoese et al (2017), Jiang et al (2017), La Salandra et al (2017), Naddeo et al (2017a,b), Tallarico et al (2017), Yin et al (2017), Miniaci et al (2018), and references therein.…”