Abstract
In this paper, a controllable colloidal damper designed to work as a vehicle suspension is experimentally investigated. In order to control the damping properties (dissipated energy and damping coefficient) as well as the elastic characteristic (spring constant) of a colloidal damper, the pressurization level inside the cylinder has to be dynamically adjusted by using a pressure controlling device. Concretely, a pumping device in communication with the cylinder, able to force the working liquid to flow into and to flow out from the cylinder is employed. In this way, a controllable parameter, called initial pressure, is adjusted to achieve ideal comfort conditions for the vehicle's passengers. First, the working principle, the main components, the model of vibration and the control system of a controllable colloidal damper are explained. Using some illustrative hysteresis change diagrams, variation of the dissipated energy, damping coefficient and spring constant versus the initial pressure is phenomenologically interpreted. Experimentally obtained results are used to validate the phenomenological model, and then to evaluate the sensitivity of the proposed system. Since the experimentally obtained damping ratio fluctuation (up to 153%), is larger than the required change of damping ratio for Kelvin-Voigt and Maxwell suspensions (133% and 100%, respectively), one concludes that the proposed controllable colloidal damper has the ability to accommodate real applications.
