Accession Number : ADA264622


Title :   Materials for Adaptive Structural Acoustic Control. Volume 4


Descriptive Note : Annual rept. 1 Feb 92-31 Jan 93,


Corporate Author : PENNSYLVANIA STATE UNIV UNIVERSITY PARK MATERIALS RESEARCH LAB


Personal Author(s) : Cross, L E


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a264622.pdf


Report Date : 06 Apr 1993


Pagination or Media Count : 147


Abstract : This report documents work carried out in the Materials Research Laboratory of the Pennsylvania State University over the first year of a new ONR sponsored University Research Initiative (URI) entitled Materials for Adaptive Structural Acoustic Control. For this report the activities have been grouped under the following topic headings: (1) General Summary Papers; (2) Materials Studies; (3) Composite Sensors; (4) Actuator Studies; (5) Integration Issues; (6) Processing Studies; and (7) Thin Film Ferroelectrics. In material studies important advances have been made in the understanding of the evaluation of relaxor behavior in the PLZT's and of the order disorder behavior in lead scandium tantalate:lead titanate solid solutions and of the Morphotropic Phase Boundary in this system. For both composite sensors and actuators we have continued to explore and exploit the remarkable versatility of the flextensional moonie type structure. Finite element (FEA) calculations have given a clear picture of the lower order resonant modes and permitted the evaluation of various end cap metals, cap geometries and load conditions. In actuator studies multilayer structures have been combined with flextensional moonie endcaps to yield high displacement (50 micrometers) compact structures. Electrically controlled shape memory has been demonstrated in lead zirconate stannate titanate compositions, and used for controlling a simple latching relay. Detailed study of fatigue in polarization switching compositions has highlighted the important roles of electrodes, grain size, pore structures and microcracking and demonstrated approaches to controlling these problems. For practical multilayer actuators a useful lifetime prediction can be made from acoustic emission analysis.


Descriptors :   *ADAPTIVE CONTROL SYSTEMS , *STRUCTURES , *ACOUSTIC MATERIALS , CONTROL , EMISSION , COMPUTATIONS , MATERIALS , DISPLACEMENT , FILMS , SOLIDS , UNIVERSITIES , LABORATORIES , ACOUSTICS , FATIGUE , YIELD , ELECTRODES , INTEGRATION , BOUNDARIES , PHASE , STANNATES , MICROCRACKING , MICROMETERS , RELAYS , SCANDIUM , PENNSYLVANIA , ZIRCONATES , SOLID SOLUTIONS , ACOUSTIC EMISSIONS , TITANATES , PICTURES , SWITCHING , BEHAVIOR , ACTUATORS , GRAIN SIZE , THIN FILMS , SHAPE , FINITE ELEMENT ANALYSIS , PREDICTIONS , METALS , POLARIZATION


Subject Categories : Acoustics


Distribution Statement : APPROVED FOR PUBLIC RELEASE