The influence of design parameters of engineered aggregate in metaconcrete on bandgap region

摘要

Metaconcrete is a new type of concrete made of partially replaced locally resonant engineered aggregates for providing enhanced blast and impact resistance. The engineered aggregate consists of solid core coated with a relatively soft material to activate the resonant behaviours of inclusion at the desired frequencies. The resonant aggregates could trigger the negative effective mass density (NEMD) of the system interacting with the applied dynamic loadings thus attenuate stress wave propagation. This unique attenuation behavior occurs only if the designed resonant frequency of engineered aggregates (f_0) is within the frequency spectrum of the applied loading. To help design metaconcrete with the desirable attenuation range for structure protection against blast loads, the frequency ranges of different blast scenarios with the scaled distance ranging from 1 m/kg~(1/3) to 10 m/kg~(1/3) are numerically investigated, the interested frequency range is found up to 50 kHz. In this study, the tunable properties of metaconcrete containing various aggregate configurations are numerically investigated by using finite element software COMSOL Multiphysics. The numerical model is calibrated first by using the results from a previous study on three-dimensional locally resonant metamaterial. With the calibrated numerical model, the frequency ranges of the NEMD of metaconcrete containing engineered aggregates in four geometric shapes are analysed. The effect of the parameters such as the aggregate shape, size, volume fraction, and material properties on the region of the NEMD are investigated. The sensitivity of the factors influencing the region of the NEMD is evaluated and discussed. The results can be used for designing engineered aggregates for better structural protections.