Engineering topics

Mathers, M. D.

Publications and source records attributed to Mathers, M. D..

3 records

NASA NTRS1976

Exploiting symmetries for efficient post-buckling analysis of composite plates

Two aspects of the post-buckling analysis of composite plates are considered in this paper. The first pertains to identifying the different types of symmetry exhibited by the pre- and post-buckling responses of rectangular and skewed composite plates. A procedure is presented for exploiting these symmetries in finite-element and finite-difference analyses. The procedure can be used with existing programs having multipoint constraint capability. The second aspect pertains to the post-buckling response of biaxially loaded composite plates. Numerical results from finite-element analysis are presented which show the range of parameters for which shear deformation and/or anisotropy are important in buckling and post-buckling analysis.

Noor, A. K.↗

NASA NTRS1975

Shear-flexible finite-element models of laminated composite plates and shells

Several finite-element models are applied to the linear static, stability, and vibration analysis of laminated composite plates and shells. The study is based on linear shallow-shell theory, with the effects of shear deformation, anisotropic material behavior, and bending-extensional coupling included. Both stiffness (displacement) and mixed finite-element models are considered. Discussion is focused on the effects of shear deformation and anisotropic material behavior on the accuracy and convergence of different finite-element models. Numerical studies are presented which show the effects of increasing the order of the approximating polynomials, adding internal degrees of freedom, and using derivatives of generalized displacements as nodal parameters.

Noor, A. K.↗

NASA NTRS1974

Nonlinear finite-element analysis of laminated composite shells

Two aspects of the geometrically nonlinear analysis of laminated composite shells are considered in this paper. The first pertains to the simplifications and computational advantages resulting from the use of group-theoretic methods in conjunction with computerized symbolic (algebraic) manipulation in the element development. The second aspect pertains to the combined effects of shear deformation and nonlinearity on the accuracy and convergence of two-dimensional, shear-flexible stiffness finite element models.

Noor, A. K.↗