Accession Number : ADA318130

Title :   Dynamic Failure Modes for Fluid-Pressure Loaded Composite Shells.

Descriptive Note : Final rept. 16 Apr 94-31 May 96,

Corporate Author : STATE UNIV OF NEW YORK AT STONY BROOK DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Kushner, Alan S. ; Nakamura, Toshio

PDF Url : ADA318130

Report Date : NOV 1996

Pagination or Media Count : 7

Abstract : Specialized tools have been developed to elucidate the fundamental mechanisms driving the interaction between delamination crack tip conditions and local and global buckling modes in two dimensional problems of compressively loaded composite flat panels and cylindrical shells. Significant progress was made in understanding the interplay between the energy going into the fracture process and the structural deformation modes. For flat composite panels subjected to compressive loadings, it was found that when a delamination was above a critical length, the postbuckling behavior shifted from stable to unstable. The bifurcation eigenvectors for the composite panels have been analyzed and it was determined that they are orthogonal for cases with a stable postbuckling path and nonorthogonal (coupled) when the postbuckling load-deflection response is unstable. It thus appears that the local energy associated with a delamination crack tip provides a mechanism for coupling the local and global buckling modes of the panel when the structural flexibilities are in a critical region.

Descriptors :   *DYNAMICS, *FAILURE, *COMPOSITE STRUCTURES, *SHELLS(STRUCTURAL FORMS), *BUCKLING, *DELAMINATION, STRUCTURAL PROPERTIES, TWO DIMENSIONAL, COMPOSITE MATERIALS, LAMINATES, LOADS(FORCES), PANELS, DEFORMATION, CRACKS, ENERGY, DEFLECTION, FRACTURE(MECHANICS), CYLINDRICAL BODIES, LENGTH, COMPRESSIVE PROPERTIES.

Subject Categories : Structural Engineering and Building Technology
      Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE