Piezoelectric ceramic insert with electrorheological fluid and its operating method

Rail-fixing anchor with a piezoelectric ceramic insert filled with electrorheological fluid for active vibration damping based on intensity

This technology features a piezoelectric ceramic insert embedded in ground or structures to secure anchor bolts. By injecting electrorheological fluid—which changes viscosity based on the applied electric field—into the space between the insert and the anchor bolt, it actively dampens vibrations according to their intensity.

Inserts and anchors used to secure rails and embedded bolts for subways and maglev trains are subject to repeated, high-intensity vibrations, which can lead to damage or detachment, posing a risk of major accidents. Previous active vibration damping technologies using piezoelectric actuators struggled to control high-intensity vibrations, while damping technologies using viscous fluids faced challenges with vertical or horizontal installation.

This technology utilizes a corrosion-resistant and fire-retardant piezoelectric ceramic insert. Fluid is filled between the case and the threaded connection, with longitudinal guide grooves on the anchor bolt and a serrated gasket facilitating fluid injection and sealing. When the vibration sensor detects low-level vibrations, voltage is applied only to the piezoelectric plate embedded with the insert. If the vibration exceeds a set threshold, voltage is also applied to the anchor coil inside the anchor bolt to increase fluid viscosity for a combined response. Applicable to subway rail fastening systems, maglev guideway embedded bolts, and foundation anchors for vibrating machinery, this system allows the piezoelectric ceramic to handle minor vibrations while the electrorheological fluid manages major ones, effectively reducing loosening and detachment accidents during train operation.

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Key Features:

• An insert embedded in ground or structures, designed to receive and secure an anchor bolt, and composed of piezoelectric ceramic material
• Electrorheological fluid filled in the space between the insert and the anchor bolt to actively dampen vibrations based on their intensity
• A plurality of piezoelectric plates embedded in the ground or structures alongside the insert to apply an electric field to the insert, connected to a control unit via electrical wires
• A control unit that adjusts the voltage applied to the piezoelectric plates and the anchor coil based on the vibration intensity measured by a vibration sensor, thereby controlling the viscosity of the electrorheological fluid

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This invention was developed with support from the Ministry of Trade, Industry and Energy for the development of low-heat cement manufacturing and utilization technology that replaces more than 5 wt.% of limestone using non-carbonate raw materials.

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