Dynamic Modelling and Experimental Testing of a Dynamic Directional Amplification Mechanism for Vibration Mitigation

Abstract

Purpose Inertial amplification of an oscillating mass has been considered by various researchers as a means to introduce enhanced vibration control properties to a dynamic system. In this paper an experimental prototype of a novel inertial amplifier, namely the Dynamic Directional Amplification mechanism (DDA), is developed and its dynamic response is subsequently evaluated. The DDA is realized by imposing kinematic constraints to the degrees of freedom (DoFs) of a simple oscillator, hence inertia is increased by coupling the horizontal and vertical motion of the model. Methods The concept and mathematical framework of the amplifier are introduced and then validated with experimental measurements conducted on the vertical shaking table, located in the Dynamics & Acoustics Laboratory, National Technical University of Athens. Results Analysis indicates the beneficial effect of the DDA to the dynamic response of the oscillator when compared to the initial structure, showcasing a decrease in the acceleration values and shift of the resonating frequency in the derived transfer functions. Conclusions The key novelty of the DDA lies in its inertial amplification properties, introduced by a simple geometry and easy-to-apply structure. The proposed framework may be incorporated in applications such as sound and vibration isolators, acoustic panels, acoustic and seismic metamaterials and other vibration control devices that aim to explore the DDA’s dynamic amplification properties. The mechanism has been previously applied by the authors to phononic and locally resonant metamaterials aiming to introduce bandgaps within the low-frequency domain. Graphical Abstract

Collaborative Design of Static and Vibration Properties of a Novel Re-Entrant Honeycomb Metamaterial

“…Metamaterials are artificial new materials with a periodic lattice arrangement, and their material properties can be artificially interfered with and adjusted through microstructural design to obtain supernatural properties that cannot be obtained in nature, such as negative stiffness [1][2][3][4][5][6], negative thermal expansion [7][8][9] and a zero Poisson or negative Poisson ratio [10][11][12][13][14][15][16]. Due to the above excellent properties, metamaterials have been highly used in the domains of mechanics [17][18][19][20], acoustics [21][22][23][24], electromagnetism [25][26][27], etc.…”

A DDA enhanced locally resonant metamaterial: experimental testing on a Lego® Technic assembly

“…Several attempts have been made [11,12], including the exploration of chirality [13] and geometrically nonlinear metamaterials [14]. Recently, Kalderon et al proposed a new class of enhanced metamaterials, including both phononic [15,16] and LR [17,18] structures, that utilize a dynamic directional amplification mechanism known as the DDA [19]. In this context, the use of dynamic directional amplification mechanisms (DDA) has been proposed as a way to enhance the performance of these materials.…”

Performance Evaluation of Distributed Extended KDamper Devices for Seismic Protection of Mid-Rise Building Structures

“…Towards this direction, Smith et al (Smith 2002) introduced the inerter, an innovative levered mass mechanism that takes advantage of the amplified inertia in order to achieve vibration control. Many research works have introduced the inerter and other amplification mechanisms as a means to enhance the performance of conventional dynamic systems and reduce mass requirements (Bhowmik and Debnath 2021;Cheng et al 2020;Chowdhury, Banerjee, and Adhikari 2022;Jangid 2021;Kalderon et al 2022;Kalderon, Mantakas, and Antoniadis 2023;Kalderon, Paradeisiotis, and Antoniadis 2021;Konstantinos A. Kapasakalis, Antoniadis, and Sapountzakis 2021b;Paradeisiotis, Kalderon, and Antoniadis 2021). In Marian & Giaralis (Marian and Giaralis 2014) and Giaralis & Taflanidis (Giaralis and Taflanidis 2018) an inerter-enhanced TMD has been proposed.…”