Accession Number : AD0714164

Title :   Static, Vibration, and Stability Analyses of Laminated Frames.

Descriptive Note : Final rept. Jul 68-Jun 69,

Corporate Author : NAVAL CIVIL ENGINEERING LAB PORT HUENEME CALIF

Personal Author(s) : Takahashi,S. K. ; Dong,S. B.

Report Date : OCT 1970

Pagination or Media Count : 47

Abstract : A two-dimensional frame of n laminations with arbitrary loadings is analyzed by the finite element method. The element is composed of bonded layers, each with a different thickness and different elastic properties. The frame is approximated by a series of short segments interconnected at the nodal points. Variational principles were applied to determine the relationship between the nodal point forces and displacements. A macroconstitutive law for laminated beams which includes the effect of transverse shear deformation is presented. This law involves a composite shape factor, which accounts for, on a weighted averaging bases, the complex stress state, the variations in strain and material properties, the geometry of the cross sections and the frequency of loading. With the aid of Castigliano's theorem, the geometric stiffness matrix is derived for problem formulations for stability and vibration under initial stress. The effect of transverse shear deformation is assessed quantitatively with examples on planar structures for which computer codes based on finite elements were used for the analysis. The results show a significant decrease in the stability and the frequencies of vibration under initial load when the geometrical configuration departs from that assumed for the classical theory. (Author-PL)

Descriptors :   (*BEAMS(STRUCTURAL), LOADS(FORCES)), LAMINATES, STRESSES, STRAIN(MECHANICS), DEFORMATION, STABILITY, VIBRATION, MATRICES(MATHEMATICS)

Subject Categories : Structural Engineering and Building Technology
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE