Accession Number : ADA326161

Title :   Characterization of the Dynamic Response of Thick Composite Structures.

Corporate Author : MAINE UNIV AT ORONO

PDF Url : ADA326161

Report Date : JUN 1997

Pagination or Media Count : 6

Abstract : The objective for this research remains at contributing to the understanding of the fundamental mechanisms which determine the response of thick composite structures to time dependent loading. The following specific objectives were originally proposed and, with some modification, continue to form the basis for the research plan: (1) Postulate the primary micromechanical attributes in the range of relatively small strain which are expected to directly affect frequencies, mode shapes, participation factors, and response magnitude. Such attributes will include material system, fiber density, ply thickness, cross ply geometry, strain rate sensitivity, accumulated damage, manufacturing imperfections, and others. (2) Choose a specific fixed free beam geometry and considering both glass/thermoset and graphite/epoxy material systems, determine dependencies of fundamental modal quantities upon micromechanical attributes determined in 1 above. Develop predictive techniques using the ABAQUS FEM code. (3) Determine candidate damage mechanisms and resulting shifts in modal variables for subject material systems under time dependent loading. (4) Characterize the currently existing knowledge base concerning micromechanical effects on modes of vibration of composite structures. The work will build upon previous effort and is directed toward specifically categorizing behavior which would then contribute to optimum design of thick composites for high strain rate shock loading. (5) Document the results in media compatible with sponsor's Mechanics of Composites Program overall objectives and guidelines.

Descriptors :   *DYNAMIC RESPONSE, *COMPOSITE STRUCTURES, *STRUCTURAL RESPONSE, *MICROMECHANICS, COMPUTERIZED SIMULATION, THICKNESS, VIBRATION, DAMAGE, TIME DEPENDENCE, LOADS(FORCES), SHAPE, STRAIN RATE, GRAPHITE EPOXY COMPOSITES, GLASS REINFORCED PLASTICS.

Subject Categories : Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE