Metamaterials are pushing the limits of traditional materials and are fascinating frontiers in scientific innovation. Mechanical metamaterials (MMs) are a category of metamaterials that display properties and performances that cannot be realized in conventional materials. Exploring the mechanical properties and various aspects of vibration and damping control is becoming a crucial research area. Their geometries have intricate features inspired by nature, which make them challenging to model and fabricate. The fabrication of MMs has become possible because of the emergence of additive manufacturing (AM) technology. Mechanical vibrations in engineering applications are common and depend on inertia, stiffness, damping, and external excitation. Vibration and damping control are important aspects of MM in vibrational environments and need to be enhanced and explored. This comprehensive review covers different vibration and damping control aspects of MMs fabricated using polymers and other engineering materials. Different morphological configurations of MMs are critically reviewed, covering crucial vibration aspects, including bandgap formation, energy absorption, and damping control to suppress, attenuate, isolate, and absorb vibrations. Bandgap formation using different MM configurations is presented and reviewed. Furthermore, studies on the energy dissipation and absorption of MMs are briefly discussed. In addition, the vibration damping of various lattice structures is reviewed along with their analytical modeling and experimental measurements. Finally, possible research gaps are highlighted, and a general systematic procedure to address these areas is suggested for future research. This review paper may lay a foundation for young researchers intending to start and pursue research on additive-manufactured MM lattice structures for vibration control applications.

In this paper, the structural behavior of a micro-electromechanical system (MEMS) composed of two electrically coupled parallel clamped-clamped microbeams is investigated. An Euler Bernoulli beam model is considered along with the nonlinear electric actuating force to get the equation of motion governing the structural behavior of the actuator. A reduced-order modeling (ROM) based on the Galerkin expansion technique, while assuming linear undamped mode shapes of a straight fixed-fixed beam as the basis functions, is assumed as a discretization technique of the equations of motion in this investigation. The results showed that the double-microbeam MEMS actuator configuration requires a lower actuation voltage and a lower switching time as compared to the single microbeam actuator. Then, the effects of both microbeams air gap depths were investigated. Finally, the eigenvalue problem was investigated to get the variation of the fundamental natural frequencies of the coupled parallel microbeams with the applied actuating DC load.

Fuel adulteration, the practice of blending lower-quality substances like kerosene with gasoline, poses significant challenges for ensuring fuel quality and safety. This study investigates two electromagnetic-based methods for detecting such adulteration: the open-ended coaxial line method and the circular waveguide method. The results reveal that the open-ended coaxial line technique is particularly effective in detecting kerosene contamination, identifying levels as low as 10% by measuring changes in the dielectric constant of the gasoline-kerosene mixture. Operating in the frequency range of 0.25–1.25 GHz, this method captures subtle changes in permittivity. In contrast, the circular waveguide method evaluates contamination by monitoring shifts in the resonance frequency of the mixture within the 10.5–11.25 GHz band, effectively identifying higher levels of contamination exceeding 10%. The resonance frequency data from this method were analyzed using linear polynomial regression, achieving a high level of accuracy with a coefficient of determination (R²) of 0.9883. These findings highlight the effectiveness of both methods in detecting fuel adulteration, with the open-ended coaxial line method showing higher accuracy in detecting lower contamination levels.