Failure Analysis of Multi-Layered, Multi-Functional Composite Structures Using a Finite Element Multicontinuum Theory

摘要

In this report, we develop a progressive failure analysis for composite structural laminates based on constituent (phase averaged) stress fields. Damage in a composite material typically begins at the constituent level and may be limited to only one constituent in some situations. An accurate prediction of constituent failure at sampling points throughout a laminate provides a genesis for progressively analyzing damage propagation in a composite structure. The failure analysis approach presented utilizes a classic strain decomposition to extract constituent stress and strain fields during a routine finite element analysis at the structural level. We refer to this approach as a Multicontinuum Theory (MCT) in recognition of the continuum nature of the constituent stress and strains. Constituent-based, quadratic, stress- interactive, failure criteria are developed to take advantage of the micro-scale information provided by MCT. The criteria are fully three-dimensional and require a minimum number of experimentally derived constants. A finite element implementation utilizing the proposed failure criteria was used to generate one- dimensional stress-strain curves and two-dimensional failure surfaces for a variety of composite laminates under uniaxial and biaxial loads. The results were shown to be superior to comparable single continuum failure analyses and in good agreement with experimentally determined failure loads.