Postbuckling analysis on delaminated composite plates under compression

Thesis/Dissertation · Tue Dec 31 23:00:00 EST 1985

OSTI ID:6510845

Yuan, F G

Failure mechanics of delamination problems in composite laminates under compression is investigated. The failure modes in general may include prebuckling, postbuckling, delamination growth and final failure. Buckling load is determined by solving and eigenvalue problem using a subspace iteration technique. The Riks-Wempner iterative scheme is then used to determine the associated postbuckling load-displacement path. Owing to local buckling of delaminated ligament, interlaminar stress transfer and strong material anisotropy, the singular stress field near the crack tip must be considered for crack stability study. A rotational, singular hybrid finite-element approach is taken for studying crack tip stresses during postbuckling. Formulation of the element stiffness matrix is based on the assumption of small strain, large rotation, and recently developed laminate elasticity solution. The variational principle of a modified hybrid functional is employed for derivation of equilibrium equations in each incremental step. Comparisons of the results obtained from this method and conventional finite elements are made to demonstrate the accuracy and efficiency of this approach. Influences of eigenfunction truncation and size of the rotational singular hybrid element on solution accuracy and convergence are studied.

• Research Organization: Illinois Univ., Urbana (USA)
• OSTI ID: 6510845
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
CARBON
COMPOSITE MATERIALS
COMPRESSION
DEFORMATION
ELASTICITY
ELEMENTAL MINERALS
ELEMENTS
EPOXIDES
FAILURES
GRAPHITE
ITERATIVE METHODS
MATERIALS
MECHANICAL PROPERTIES
MINERALS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
STRESS ANALYSIS
TENSILE PROPERTIES