Abstract: A method and device for calculating an optimal leveling stiffness of pile top displacement regulators in a composite foundation are disclosed. The method includes: determining basic parameters for calculating the optimal leveling stiffness of the pile top displacement regulators in the composite foundation; building an optimal mathematical model for calculating the optimal leveling stiffness of the pile top displacement regulators in the composite foundation, and solving the optimal mathematical model for calculating the optimal leveling stiffness of the pile top displacement regulators in the composite foundation to obtain the optimal leveling stiffness. The method and device maximize the bearing capacity of the composite foundation by taking an optimal value of the leveling stiffness of the pile top displacement regulators. The method and device realize accurate quantitative analysis for composite foundation design by adjusting the value of the leveling stiffness of the pile top displacement regulators.

Abstract: An ultrasonic motor-based regulated variable-damping vibration isolator, includes a base, a magnetorheological damper, and an adapter plate. The magnetorheological damper is mainly used to support and deplete the energy of vibration; the magnetorheological damper includes an upper cavity, a lower cavity, a connecting ring, a permanent magnet, orifices, a magnetic permeable ring, an ultrasonic motor and the like; a magnetorheological fluid is stored in the upper and lower cavities defined by bellows. The magnetorheological damper uses the ultrasonic motor to drive the permanent magnet to rotate to adjust the overlap ratio of the permanent magnet and the orifices, that is, to adjust the number of the orifices entering the magnetic field of the permanent magnet, so as to change the damping intensity of the damper. After rotating in place, the ultrasonic motor can be powered off and self-locked.