Accession Number:

ADA209294

Title:

Analytical and Numerical Methods for Composite Materials

Descriptive Note:

Final rept. Dec 1986-Jun 1987

Corporate Author:

SYSTEMS ENGINEERING INC GREENBELT MD

Personal Author(s):

Report Date:

1987-07-16

Pagination or Media Count:

95.0

Abstract:

Analytical and computational models of fiber reinforced composite materials are constructed using a mathematical procedure called homogenization. The procedure is systematic i.e., one can estimate the precision of the approximations to the field equations of the composite. Moreover, it retains interaction effects due to the microstructure of the composite in the macroscopic approximations. A software system, MeMCAP, based on finite element methods implements the methodology for evaluation of macroscopic effective moduli of the composite and for computation of the microscopic stress and strain fields acting at the fiber-matrix interfaces. The software system is designed for easy use by engineers who need not be familiar with the underlying analytical techniques. Interaction takes place through a menu-driven control structure which requires specification of the material properties of fiber and matrix and of the geometry of a typical cell of the composite. The homogenization method produces an effective parameter model of the macroscopic behavior of the material longitudinal and transverse Youngs moduli, Poisson coefficients, etc., and a description of the microscopic distributions of stress within the cell - especially at the fiber-matrix interface. The system can treat composites with various fiber shapes and packing arrangements. It can also treat multi-ply laminates. The program, written in Fortran, is fast and efficient. Extensions of the work to encompass dynamical phenomena such as the propagation and dispersion of stress waves, thermal properties, and estimation of the onset of fractures are also discussed.

Subject Categories:

  • Laminates and Composite Materials

Distribution Statement:

APPROVED FOR PUBLIC RELEASE