Design and testing of a frictionless mechanical inerter device using living-hinges

Abstract

In this paper a novel type of frictionless mechanical inerter device is presented, where instead of gears, motion of the flywheel is achieved using living-hinges. The design is a type of pivoted flywheel inerter inspired in part by the Dynamic Anti-resonant Vibration Isolator (DAVI) concept, which was first developed in the 1960s. Unlike the DAVI, it will be shown that the pivoted flywheel inerter has the advantage of producing balanced forces. Furthermore the use of living-hinges eliminates the need for gears or other frictional elements in the inerter mechanism. To demonstrate the utility of the new concept, a bench-top experiment was performed using a small-scale living-hinge inerter manufactured using polypropylene hinges. By estimating the experimental system parameters, the transmissibility results from the experiment could be compared to a mathematical model. These results showed that the living-hinge inerter provided an isolation effect of at least three orders of magnitude in terms of the maximum amplitude reduction from the uncontrolled system compared to that with the inerter added. Although friction was eliminated, the living-hinges did introduce additional damping, and this was found to correspond to an increase in the equivalent damping ratio for the uncontrolled system of 1.2%. It is shown that the living-hinge inerter developed in this paper fits all of the essential conditions required to be a practical inerter device. Furthermore, as it operates without mechanical friction, or fluid flow, it represents a new paradigm in experimental inerter technology.

Damping enhancement principle of inerter system

“…Subsequently, Ikago and his coworkers proposed a two‐terminal inertial system (tuned viscous mass damper [TVMD]), which explicitly used mass enhancement and damping enhancement for the first time . The concept of the inerter has made many studies focus on new inerter mechanisms and structural vibration mitigation by using various inerter systems …”

“…47,54,55 The concept of the inerter has made many studies focus on new inerter mechanisms and structural vibration mitigation by using various inerter systems. [56][57][58][59][60][61][62][63][64][65] In addition to the development of new devices, there is another key issue in the research and development of an inerter system, namely, the parameter determination of its components. Based on fixed-point theory (tuning theory), 66 Ikago et al 47 provided close-form optimum design equations for the TVMD.…”

Statistical seismic performance assessment of tuned mass damper inerter

“…RID (VMD), TVMD (SPIS-II), and TID (SPIS-I) are three popular inerter-based damping systems that have been used self-sufficiently to control the structural vibrations under seismic loads by Hwang et al, 28 Ikago et al, 15 and Lazar et al, 25 respectively. Hwang et al 28 employed a VMD to control structural vibrations; however, they used toggle brace systems to improve F I G U R E 2 Different inerter realization for converting translation motion to rotational motion: (a) ball-screw, 3 (b) rack and pinion, 4 (c) helical fluid, 5 (d) gyro-mass damper, 19 (e) living-hinge, 20 and (f) hydraulic inerter 21 the damping mechanism, whereas Ikago et al 15 incorporated the VMD with a tuning spring and proposed a tuned viscous mass damper (TVMD). 15 Subsequently, Lazar et al 25 analyzed the ability of TID to control civil engineering structures and emphasized its advantage over TMD which can reduce the required physical tuned mass to achieve a lightweight passive control.…”

The Effects of Parasitic Mass on the Performance of Inerter-Based Dynamic Vibration Absorbers

“…There are three types of inerter which have been mostly studied in the literature: the ball-screw inerter [6], the rack and pinion inerter [5,6], and the fluid inerter [7]. Recently, the frictionless mechanical inerter that consists of a disc as flywheel and the living-hinges was presented to eliminate the friction that is caused by gears or ball-screw interaction [8]. Inerter-based vibration absorbers have been studied to improve the vibration performance of the system in vehicle suspensions [9,10], civil engineering applications [11,12,13], landing-gear systems [14] and machining applications [15,16].…”