Laboratory experimental testing of inerters

This paper presents experimental results from the testing of mechanical networks involving inerter devices. The tests are carried out using a hydraulic ram actuator whose displacement is controlled in a closed-loop system. A methodology is proposed for the testing of inerter devices which amounts to the design of a buffer network to be connected in series with the inerter device during testing. This avoids instability and nonlinear phenomena which are otherwise observed with the testing of inertial loads using this type of hydraulic actuator. It is shown that the admittance of the inerter devices approaches the ideal inerter admittance over a useful frequency range.