Energy Absorbing System for Safeguarding Structures from Disruptive Forces

Abstract

The invention is a system and method for automatically adjusting the resonance frequency of an energy absorbing device in response to a disruptive force. By configuring an energy absorbing device for automatic response tuning, utilizing a controller coupled to one or more sensors for processing a determination primarily based on sensing data, the natural period of an overall structure may be adjusted (i.e. increased or decreased) so that the acceleration response of the structure is decreased upon being subjected to a disruptive force, for example, high winds, a blast from an explosion, or a seismic force caused by an earthquake.

What is claimed is: 
     
         1 . An automatic energy dissipation system, comprising:
 a sensor for detecting a disruptive force applied to a building;   a processor connected to the sensor, configured for determining a control signal based on a sensing data received from the sensor;   an energy absorbing device, comprising an enclosure with a variable stiffness, the enclosure configured to house an energy absorbing material; and   an actuator, coupled to said processor and connected to the energy absorbing device, for adjusting the rigidity of the enclosure, wherein adjusting the rigidity of the enclosure results in tuning the energy absorbing device based on the control signal generated by the processor in order to alter a resonance frequency of said building.   
     
     
         2 . The system of  claim 1 , wherein the energy absorbing device is installed between a superstructure of the building and a foundation of the building, in a manner so that the superstructure is isolated from the foundation. 
     
     
         3 . The system of  claim 1 , wherein the tuning of the energy absorbing device comprises altering a resonance frequency of the building to reduce a structural response to the disruptive force applied to the building. 
     
     
         4 . The system of  claim 1 , wherein the tuning of the energy absorbing device comprises generating a damping force to reduce a structural response to the disruptive force applied to the building. 
     
     
         5 . The system of  claim 4 , wherein the damping force comprises viscous damping. 
     
     
         6 . The system of  claim 4 , wherein the damping force comprises hysteretic damping. 
     
     
         7 . The system of  claim 4 , wherein the energy absorbing device is configured as a variable friction damper. 
     
     
         8 . The system of  claim 4 , wherein the energy absorbing device is configured as a variable viscous damper. 
     
     
         9 . The system of  claim 1 , wherein the energy absorbing device is a base isolator configured for:
 adjusting a resonance frequency of the building; and   generating a damping force to reduce a structural response to the disruptive force applied to the building.   
     
     
         10 . The system of  claim 9 , wherein the base isolator further comprises:
 a base adapted to attach to a support member of the building; and   a cover coupled to the base in a manner so as to form the enclosure, wherein the cover is adapted to attach to the base and the building; and wherein the enclosure is coupled to the actuator in a manner so that the rigidity of the enclosure may be controlled by activating the actuator.   
     
     
         11 . The system of  claim 10 , wherein the cover of the base isolator further comprises:
 a rigid layer;   a resilient layer; and   a plurality of side plates;   wherein the rigid layer and the resilient layer are substantially semicircular in shape, having substantially the same center and having respective ends configured to attach to the base; and   wherein the rigid layer acts as a restraining material for the resilient layer when the disruptive force is applied to the cover.   
     
     
         12 . The system of  claim 11 , wherein the resilient layer of the cover is securely sandwiched between the side plates, the side plates being coupled to the actuator to adjust the damping force when the actuator is activated for the tuning. 
     
     
         13 . The system of  claim 11 , wherein the cover is coupled to the support member of the building near a top portion of the semicircular shape of the rigid and resilient layers. 
     
     
         14 . The system of  claim 13 , wherein the respective ends of the cover are coupled to a foundation of the building to provide a constant factor of initial and sliding friction between the rigid layer and the resilient layer for transferring tension and shear forces away from the building. 
     
     
         15 . The system of  claim 14 , further comprising a plurality of actuators adapted to attach to the cover at the respective ends and the top portion of the semicircular shape for:
 tuning the constant factor of initial and sliding friction between the rigid layer and the resilient layer; and   tuning the transferring tension and shear forces away from the building.   
     
     
         16 . The system of  claim 10 , wherein the energy absorbing material enclosed in the cover of the base isolator further comprises a granular material, which provides vertical strength and allows for sideways slip when the disruptive force is applied. 
     
     
         17 . The system of  claim 10 , wherein the energy absorbing material enclosed in the cover of said base isolator further comprises a liquid, which provides vertical strength and allows for sideways slip when said disruptive force is applied. 
     
     
         18 . The system of  claim 17 , wherein the cover further comprises a valve to transfer the liquid into a spring loaded chamber whenever the disruptive force is applied; the spring loaded chamber having a spring positioned to push the liquid back into the cover whenever the cover is relieved from the disruptive force.