Higher-order individual-layer theory of laminated composites
A new higher-order individual-layer theory is developed for laminated plates. The theory approximates the in-plane and thickness normal displacements by third and second order functions of each layer's thickness coordinates, respectively. More importantly, the theory treats each layer separately and satisfies the displacement compatibility and stress equilibrium conditions along the interfaces between adjacent layers. Also, transverse loads on the top and bottom surfaces are accounted for explicitly. Since each layer is considered separately, the present theory better accounts for the nonhomogeneity of a laminate through the thickness. For the validation of the present theory, cylindrical bending and rectangular plate bending of unimodular and bimodular laminates, free vibration, and forced vibration with material damping effects are analyzed. Numerical results obtained for the present theory are compared with those obtained by elasticity theory and/or approximate laminated plate theories. The comparisons show that the present theory predicts more accurate stress distributions through the thickness of a laminate, more accurate deflections, neutral-surface positions for bimodular laminates, as well as more free vibration modes than any other approximate theory. Also, the higher-order individual-layer theory allows the thickness shear strain to vary from layer to layer. The final application is to thermal stress analysis of a laminated plate in cylindrical bending. The analytical approach used here is the eigenvalue expansion approach. The numerical results are compared with results by the finite element method and other approximate theories. The present theory predicts relatively accurate stress distributions along the interface compared with the FEM results. Especially, the present theory seems to predict more accurate distributions of thickness shear and peeling stresses than other approximate theories.
- Research Organization:
- Oklahoma Univ., Norman, OK (USA)
- OSTI ID:
- 5975771
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360603* -- Materials-- Properties
42 ENGINEERING
420200 -- Engineering-- Facilities
Equipment
& Techniques
ANALYTICAL SOLUTION
BENDING
COMPARATIVE EVALUATIONS
COMPOSITE MATERIALS
DAMPING
DIMENSIONS
LAYERS
MATERIALS
MATHEMATICAL MODELS
MECHANICAL VIBRATIONS
NUMERICAL SOLUTION
PLATES
STRESS ANALYSIS
STRESSES
TESTING
THERMAL STRESSES
THICKNESS
VALIDATION