Abstract: Modular control patches including assemblies of sensors and actuators are provided to impart or control vibration of foundation members such as struts in aerospace apparatus. Local digital electronic control means is associated with each control patch assembly. Programmable digital compensators in the control permits operation of the patches to be remotely varied. Patches are attached mechanically or by chemical bonding to the outside of the struts so that the electronics can be selectively removed and replaced. The patch being the sensors and actuators may also be attached or embedded with a composite structure.

Abstract: Modular control patches including assemblies of sensors and actuators are provided to impart or control vibration of foundation members such as struts in aerospace apparatus. Local analog electronic control means is associated with each control patch assembly. Patches are attached mechanically or by chemical bonding to the outside of the struts. The corresponding electronics can be selectively removed and replaced. The patch being the sensors and actuators may also be attached or embedded with a composite structure.

Abstract: Modular control patches including assemblies of sensors and actuators are provided to impart or control vibration of foundation members such as struts in aerospace apparatus. Local analog electronic control means is associated with each control patch assembly. Patches are attached mechanically or by chemical bonding to the outside of the struts. The corresponding electronics can be selectively removed and replaced. The patch being the sensors and actuators may also be attached or embedded with a composite structure.

Abstract: A piezoelectric actuator/sensor package and corresponding method for its fabrication, and a method of embedding a ceramic actuator/sensor in a laminated structural member, such as a graphite-epoxy laminate. A ceramic actuator/sensor, with lead wires first bonded to it, is encapsulated in a non-conductive fiber composite material, such as fiberglass cloth and epoxy, to form a package that is precured at a suitable temperature, typically room temperature. Encapsulation provides electrical insulation, good strain coupling, protection from mechanical damage, and reduction in thermal stresses, since the coefficient of thermal expansion of the encapsulating material is selected to be between those of the ceramic and the graphite-epoxy laminate. Graphite fibers may be added to the package to enhance voltage-strain performance. The package is embedded in the structural laminate and the composite structure is cured in a manner that minimizes thermally-induced stresses.