Analysis and experiment of small size magnetorheological fluid damper for time delay

Magnetorheological (MR) fluid is a new kind of intelligent material. It responds quickly to an applied magnetic field with a change in its rheological properties. MR fluid dampers are a class of adjustable damping elements and their reversible changes can be controlled by magnetic field. This paper uses MR dampers' damp characteristics to complete a function of short time delay, and the damper's volume is smaller than the other dampers that have been applied for other uses. This kind of damper can be used as a time delay fuse for explosive or for the delayed operation of a mechanical or fluidic circuit. In this paper, there are two types of structures for time delay been discussed, gap structure MR time delay device and holes structure MR time delay device, and then the ANSYS software is used for simulation the magnetic circuit. In order to estimate the two kinds of devices' delay time, mathematical modeling and experimental testing are built in this paper. From the experiment results, we know that holes structure does not always implement theoretical delay time, but the gap structure can complete the time delay function satisfactory. Finally, we reprocess the holes structure MR time delay device by widening holes' diameter from 1 mm to 2 mm, and the experiment results using new devices consistent with the theoretical results.