Analysis on the Dynamic Wave Attenuation Properties of Metaconcrete Considering a Quasi-Random Arrangement of Inclusions

Abstract

The mitigation properties of metaconcrete cast with two types of resonant inclusions are assessed through wave transmission tests. Three cylindric metaconcrete specimens of regular size (20 cm height, 10 cm diameter), containing an equal number of different type of inclusions disposed in a semi-regular lattice, are tested in the longitudinal direction within the sonic range of frequencies. Inclusions, bi-material spheres consisting of a heavy core coated with a soft material, are characterized by a resonant behavior, evaluated numerically with a finite element modal analysis of a unit metaconcrete cell. Each metaconcrete specimen contains six layers consisting of six engineered aggregates of different type. Inclusions are disposed by rotating each layer with respect to the adjacent ones, as so as to create a pseudo-random arrangement. Specimens are excited by a sinusoidal signal of linearly growing frequency, sweeping a range centered at the translational eigenfrequency of the resonant inclusion. A standard plain concrete specimen is used as reference to define a transmissibility coefficient, that facilitates the quantification of the attenuation properties. With respect to plain concrete, all metaconcrete specimens show a marked (up to 80–90%) attenuation of the transmitted signal in proximity of the numerically estimated eigenfrequency of the inclusion. The intensity of the attenuation is weakly dependent on the type of the inclusion, while the frequency where the attenuation is observed depends markedly on the inclusion type. As a very positive quality in the view of practical applications, experimental results confirm that the attenuation effectiveness of metaconcrete is not related to the ordered microstructural arrangement.

Effect of Resonant Aggregate Parameters in Metaconcrete Thin Plates on Flexural Bandgaps: Numerical Simulations

“…Numerical studies have been carried out demonstrating the reduction for both longitudinal and transverse vibration modes of metaconcrete [12][13][14][15][16][17][18][19] , in addition to experimental validations endorsing this behavior [20][21][22] , even if the inclusions are dispersed in a random 23,24 or quasi-random arrangement 25 . Furthermore, a simplified analytical model for metaconcrete filled with randomly distributed resonators has been proposed 26 .…”

Design and evaluation of dual-resonant aggregates metaconcrete

“…Briccola et al (2017) studied the attenuation properties of metaconcrete by nondestructive dynamic tests and observed a remarkable 2 order of magnitude reduction in the amplitude of the transmitted signal in metaconcrete relative to conventional concrete. Briccola et al (2021), studied the attenuation properties of metaconcrete containing two types of resonant inclusions in the sonic range and found that with respect to plain concrete, all metaconcrete specimens showed a marked (up to 80-90%) attenuation of the transmitted signal in proximity of the numerically estimated eigenfrequency of the inclusion. Kettenbeil & Ravichandran (2018) conducted plate impact experiments to study the dynamic responese of metaconcrete specimen and found that compared with a homogeneous epoxy specimen, the metaconcrete specimen led to a reduction in maximum strain of up to 72%.…”

Experimental Validation of Dynamic Response of Small-Scale Metaconcrete Beams at Resonance Vibration

“…Ref. [ 19 ] employed the cylindrical specimens in the test too. The inclusions were arranged in a semi-regular lattice-like pattern.…”

“…The pattern was rotated in every specimen to obtain a pseudo-random arrangement. In the studies in [ 17 , 18 , 19 ], the specimen of concrete with standard aggregate was used as a reference. Comparing the results of the metaconcrete specimen with the reference specimen revealed a remarkable attenuation of the transmitted signal in the proximity of the inclusion’s natural frequencies.…”