Accession Number:

ADA278397

Title:

Structural Integrity of Intelligent Materials and Structures

Descriptive Note:

Rept. for 1 Jul 1993-31 Jan 1994

Corporate Author:

CSA ENGINEERING INC PALO ALTO CA

Personal Author(s):

• Gibson, Warren C.
• Fowler, Bryce L.

Report Date:

1994-02-25

Pagination or Media Count:

48.0

Abstract:

Intelligent materials open new avenues to improve performance, reliability, and longevity of future aerospace vehicle structures by allowing the materials themselves to become active elements for multiple system functions. However, the application of intelligent materials and structures has been inhibited because the effects of microstructural interactions between intelligent and host material elements have heretofore not been well characterized. This research implemented and applied three analytical approaches to the study of stress concentrations and cracking around embedded sensor actuator elements. One was an analytical method based on high-order Ritz functions for accurate representation of steep strain gradients. The second was a conventional finite element approach using very fine meshes, and the third was a finite-element-based computation of energy release rates suitable for predicting crack growth. Among other interesting results, the analyses compared the effects of applied loads with the effects of actuation strains and found that the applied loads were more likely to cause cracking or delamination.

Descriptors:

• *COMPOSITE MATERIALS
• *LAMINATES
• *AEROSPACE CRAFT
• MICROSTRUCTURE
• LIFE EXPECTANCY(SERVICE LIFE)
• CRACKING(FRACTURING)
• MATRIX MATERIALS
• CERAMIC MATERIALS
• EMBEDDING
• AXIAL LOADS
• DELAMINATION
• FAILURE(MECHANICS)
• ACTUATORS
• STRUCTURAL RESPONSE
• RELIABILITY
• STRAIN(MECHANICS)
• DISPLACEMENT
• LOADS(FORCES)
• INTERACTIONS
• POLYMERS

Subject Categories:

• Research and Experimental Aircraft
• Laminates and Composite Materials

Distribution Statement:

APPROVED FOR PUBLIC RELEASE