Comparison of frequency characteristics in a damper using magnetic fluid, ER fluid dispersing smectite, and mixed ER magnetic fluid

This paper presents a new type of damper using electro-rheological (ER) magnetic fluid for improving magnetic fluid damper and ER fluid damper. Silicone oil based magnetic fluid dispersing 10 nm size of magnetite, silicone oil based ER fluid dispersing 2 nm to 50 nm size of smectite and a mixture, that is, ER magnetic fluid have been used in a piston type damper. Dynamic visco-elasticities of these fluids have been measured by considering chain (cluster) formations. Next, frequency characteristics of transmissibility (magnification factor) and phase in damper have been compared with those fluids under magnetic field, electric field and both fields. The Voigt or Maxwell model can be applied in those dampers depending on amplitude. ER magnetic fluid has showed the decrease of amplitude ratios at resonance point and higher frequency at any amplitude under both magnetic and electric fields as low-pass filter.