Accession Number : ADA135997

Title :   Formulation of a Nonlinear, Compatible Finite Element for the Analysis of Laminated Composites.

Descriptive Note : Doctoral thesis,


Personal Author(s) : Witt,W P , III

PDF Url : ADA135997

Report Date : Dec 1982

Pagination or Media Count : 130

Abstract : Increased use of laminated composites has pointed out the need for better analytic tools. These tools must be able to correctly account for normal shear in the laminates and should be able to solve nonlinear problems. The finite element method can be applied to analyze laminated composites, and this research presents a new and unique method to include nonlinear effects and normal shear effects. The finite element is formulated from basic elasticity equations. The most unique characteristic of the element is the manner in which normal shear is handled. The normal to a reference surface is allowed to not only rotate but also to change shape. Not only is displacement continuity imposed at lamina interfaces, but also slope continuity is guaranteed. After a complete general formulation of the finite element is presented, the method is specialized to plates so that the convergence characteristics, the accuracy, and the applicability of the element can be studied. The finite element does an excellent job of analyzing laminated composites, although there is some degradation in accuracy as the plates become thinner. This finite element gives the analyst the ability to do nonlinear analysis of laminated composites under a variety of loading and boundary conditions. (Author)

Descriptors :   *Finite element analysis, *Nonlinear analysis, *Composite materials, *Laminates, *Displacement, Plates, Normality, Shear properties, Loads(Forces), Boundaries, Three dimensional, Convergence, Accuracy, Elastic properties, Continuity, Surfaces

Subject Categories : Laminates and Composite Materials
      Numerical Mathematics

Distribution Statement : APPROVED FOR PUBLIC RELEASE