Magnetorheological damper and use thereof

Abstract

An magnetorheological damper useful in structural vibration control has a damper body and a moveable portion relative to the damper body. The damper includes an magnetorheological material contained within the damper body for resisting movement of the moveable portion. Rheology changes can be generated in the magnetorheological material owing to changes in a magnetic field, to which the magnetorheological material is exposed. The damper further includes at least a sensor embedded in the damper for monitoring an external force exerted on the damper, and for generating a signal to control the magnetic field and hence the resulting yield force and rheological damping of the damper in response to a variance in the external force.

1 . An magnetorheological damper useful in structural vibration control, having a damper body and a moveable portion relative to the damper body, comprising: 
 an magnetorheological material contained within the damper body for resisting movement of the moveable portion, wherein rheology changes can be generated in the magnetorheological material owing to changes in a magnetic field, to which the magnetorheological material is exposed; and    at least a sensor embedded in the damper for monitoring an external force exerted on the damper, and for generating a signal to control the magnetic field and hence the resulting yield force and rheological damping of the damper in response to a variance in the external force.    
   
   
       2 . The damper of  claim 1 , wherein the sensor is a piezoelectric sensor.  
   
   
       3 . The damper of  claim 2 , wherein the sensor includes at least one pair of planar electrodes separated by a piezoelectric wafer, held together in a stack against one another under pressure.  
   
   
       4 . The damper of  claim 3 , wherein the sensor further includes an insulating wafer for insulating one of the electrodes.  
   
   
       5 . The damper of  claim 3 , wherein the piezoelectric wafer is cylindrical.  
   
   
       6 . The damper of  claim 3 , wherein the piezoelectric wafer is made of one of piezoelectric ceramic, polymer, and composite materials.  
   
   
       7 . The damper of  claim 3 , wherein the sensor includes a plurality of pairs of planar electrodes each separated by a piezoelectric wafer, and wherein the pairs of planar electrodes and wafers are held together in a stack against one another under pressure.  
   
   
       8 . The damper of  claim 7 , wherein if the number of the piezoelectric wafers is odd, the sensor further includes an insulating wafer for insulating one of the electrodes.  
   
   
       9 . The damper of  claim 7 , wherein the piezoelectric wafers are cylindrical.  
   
   
       10 . The damper of  claim 7 , wherein the piezoelectric wafers are made of one of piezoelectric ceramic, polymer, and composite materials.  
   
   
       11 . The damper of  claim 7 , wherein the piezoelectric wafers are made in different electrode patterns, or different forms of “active” and “inactive” areas, at least including whole-face, inner, in-between, and outer electrode patterns.  
   
   
       12 . The damper of  claim 1 , wherein the sensor is mounted at a longitudinal end of the damper.  
   
   
       13 . A structural vibration control system, comprising: 
 at least an magnetorheological damper, having a damper body and a moveable portion relative to the damper body, including 
 an magnetorheological material contained within the damper body for resisting movement of the moveable portion, wherein rheology changes can be generated in the magnetorheological material owing to changes in a magnetic field, to which the magnetorheological material is exposed; and  
 at least a sensor embedded in the damper for monitoring an external force exerted on the damper, and for generating a signal to control the magnetic field and hence the resulting yield force and rheological damping of the damper in response to a variance in the external force; and  
   means for receiving the signal from the sensor and for varying the magnetic field in accordance with the signal.    
   
   
       14 . The system of  claim 13 , wherein the sensor is a piezoelectric sensor.