The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 18, 2000
Filed:
Jul. 21, 1998
Horst Bansemir, Munich, DE;
Stefan Emmerling, Neubiberg, DE;
Eurocopter Deutschland GmbH, Munich, DE;
Abstract
A composite structure (3) includes a piezoelectric element (1) sandwiched between fiber composite panels (2). The composite structure can be used as an actuator element. In a method for producing the composite structure, the fiber composite panels are pre-stressed and pre-strained by applying respective pre-stressing forces (F.sub.1, F.sub.2) in opposite directions along two substantially perpendicular axes in the plane of the panel. The pre-stressed and pre-strained condition of the fiber composite panels (2) is maintained, while the panels are adhesively bonded (5) surfacially onto the piezoelectric element (1). After the bonding is completed, the pre-stressing forces are removed from the fiber composite panels. As a result, in the finished composite structure (3), the fiber composite panels (2) are under internal tension, while the piezoelectric element (1) is under internal compression. The pre-stressing forces (F.sub.1, F.sub.2) are particularly selected in magnitude and direction to achieve the required resultant balance of tension and compression within the composite structure (3). The pre-compression of the piezoelectric element (1) should be sufficient so that operating loads on the composite structure do not result in tension loading of the piezoceramic element, while substantially maintaining the useful active strain range of the overall composite structure.