The plates may be actuators, which couple energy into the attached structure, or sensors which respond to {HEAD ~ strain} coupled from {TAIL ~ the attached structure} 
coupled from
The plates may be actuators , which couple energy into the attached structure , or sensors which respond to { HEAD ~ strain } coupled from { TAIL ~ the attached structure }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL