Showing papers on "Composite laminates published in 1969"

Exact solutions for composite laminates in cylindrical bending

Abstract: Limitations of classical laminated plate theory are investigated by comparing solutions of several specific boundary value problems in this theory to the corresponding theory of elasticity solutions. The general class of problems treated involves the geometric configuration of any number of isotropic or orthotropic layers bonded together and subjected to cylindrical bending. In general it is found that conventional plate theory leads to a very poor description of laminate response at low span-to-depth ratios, but converges to the exact solution as this ratio increases. The analysis presented is also valid in the study of sandwich plates under cylindrical bending.

On the Solution of Plates of Composite Materials

Abstract: In the analysis of anisotropic plates, the twist-coupling terms involving Dls and D26 are generally neglected in prescribing the simply supported boundary conditions and may be referred to many papers and reports such as [1]. Recent attempts [2] were made for the determination of buckling loads of rectangular homogeneous anisotropic plates of composite materials where the moment curvature relations involve mixed derivatives of the transverse displacement with respect to x and y. Deformation surfaces assumed in double Fourier series were used in conjunction with Lagrange multipliers method [3,4] in the energy formulation of the problems. The analysis yields excellent results for completely clamped plates. However, the assumed series diverges for simply supported plates. A double power series solution was then used and the assumed

Comparison of composite and noncomposite structural tubes.

Abstract: The tubular cross section is known to be an efficient configuration for structural members. Composite tubular members are of interest because of their structural efficiency and because they can be easily fabricated with any desired laminate pattern by automated techniques. This study was initiated to determine the structural properties of composite tubes and compare them to conventional metal tubes. The characterization of composite tubes was accomplished analytically and verified experimentally. Materials considered in the study included glass/epoxy, boron/epoxy, steel, aluminum, and titanium. The criterion selected for comparison of materials was weight/strength efficiency. Results of the study are summarized in plots of weight/strength parameters vs structural indices for various types of loading. The resulting charts enable a direct comparison of material merits. Significant potential advantages are revealed which could be realized by utilizing structural tubes from the composite materials investigated.