A new ideal mechanical one-port network element named the inerter was recently introduced, and shown to be realisable, with the property that the applied force is proportional to the relative acceleration across the element. This paper makes a comparative study of several simple passive suspension struts, each containing at most one damper and inerter as a preliminary investigation into the potential performance advantages of the element. Improved performance for several different measures in a quarter-car model is demonstrated here in comparison with a conventional passive suspension strut. A study of a full-car model is also undertaken where performance improvements are also shown in comparison to conventional passive suspension struts. A prototype inerter has been built and tested. Experimental results are presented which demonstrate a characteristic phase advance property which cannot be achieved with conventional passive struts consisting of springs and dampers only.

In 2008, two articles in Autosport revealed details of a new mechanical suspension component with the name "J-damper" which had entered Formula One Racing and which was delivering significant performance gains in handling and grip. From its first mention in the 2007 Formula One "spy scandal" there was much speculation about what the J-damper actually was. The Autosport articles revealed that the J-damper was in fact an "inerter" and that its origin lay in academic work on mechanical and electrical circuits at Cambridge University. This article aims to provide an overview of the background and origin of the inerter, its application, and its intimate connection with the classical theory of network synthesis.

This article proposes a novel hydraulic inerter and experimentally verifies its properties. The inerter is a true two-terminal mechanical network element, which was invented to substitute for the mass in mechanical/electrical analogies. Previously, inerter concepts have been realized by rack-and-pinion and ball-screw devices. This article introduces a new hydraulic inerter device in which the forces are translated by hydraulic means. The dynamics of the device is discussed and experimentally verified. On the basis of the results, the proposed hydraulic inerter is shown to be effective.

This paper investigates the performance benefits of train suspension systems employing a new mechanical network element called an inerter. An inerter is a true mechanical two-terminal element with the applied force proportional to the relative acceleration across the terminals. Until now, ideal inerters have been applied to car and motorcycle suspension systems, for which a significant performance improvement was reported. In this paper, we discuss the performance benefits of train suspension systems employing inerters. The study was carried out in three phases. First, fixed suspension structures were applied to train suspension systems, and optimised for two performance measures. Secondly, this optimisation was further carried out using linear matrix inequality approaches to discuss the achievable performance of passive networks. The resulting networks can then be realised by synthesis methods, such as the Brune and Bott–Duffin realisation. Finally, the nonlinear properties of inerter models and their impact on system performance were discussed. From the results, the inerter was deemed effective in improving the performance of train suspension systems.

This article investigates the performance benefits of building suspension systems that employ a newly developed mechanical element called an inerter. The inerter was proposed as a genuine two-terminal mechanical device to substitute for the mass element, which allows mechanical and electrical networks to become truly analogous. This study applied inerters to building suspension control. First, a one-degree-of-freedom (DOF) building model was examined in order to show the significant performance improvement by inerters, especially with a multi-layer design. Second, the discussion was extended to a two-DOF building model. Finally, a ball-screw inerter was constructed for testing. From the results, the inerters were deemed effective in reducing building vibrations.

This paper discusses the nonlinear properties of inerters and their impact on vehicle suspension control. The inerter was recently introduced as an ideal mechanical two-terminal element, which is a substitute for the mass element, where the applied force is proportional to the relative acceleration across the terminals. Until now, ideal inerters have been applied to vehicle, motorcycle and train suspension systems, in which significant performance improvement was achieved. However, due to the mechanical construction, some nonlinear properties of the existing mechanical models of inerters are noted. This paper investigates the inerter nonlinearities, including friction, backlash and the elastic effect, and their influence on vehicle suspension performance. A testing platform is also built to verify the nonlinear properties of the inerter model.