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