Composites Failure Criteria, Uncertainty Propagation, and Estimation of the A-Basis and B-Basis Design Allowables

Published

July 7, 2012

Author(s)

Jeffrey T. Fong, Nathanael A. Heckert, James J. Filliben

Abstract

In a 2002 paper on a summary of the so-called World-Wide Failure Exercise by Hinton, Kaddour, and Soden (Composites Science and Technology, 62: 1725-1797), in which fourteen deterministic theories for predicting failure in composite laminates were "tested" against experimental evidence using point estimates and mean values, the authors concluded that "the theories were not sufficiently robust" and "the designer wishing to estimate the stress levels at which ultimate failure might occur in a multi-directional laminate, can, at best, hope for accuracy of ±50 % in the majority of cases." This assessment posed a major challenge to the 30-year-old composite materials industry, which introduced carbon-fiber-reinforced-plastics components replacing metal items on aircrafts as early as 1979. The purpose of this paper is to propose an alternative approach of "testing" theories against experiments by using interval estimates and the associated concept of uncertainty, whereby the stress (and/or strain) variables and the material property parameters in each failure criterion are considered stochastic rather than deterministic. In this approach, we assume that the uncertainty of all material property parameters as measured by the so-called coefficient of variation, c , is small (i.e., 0

Citation

Composites Part A-Applied Science and Manufacturing

Pub Type

Journals

Keywords

A-basis design allowable, B-basis design allowable, coefficient of variation, coverage, composites laminates, composites failure criteria, DATAPLOT, error propagation, stochastic formulation, tolerance limits, uncertainty metric, uncertainty quantification.

Citation

Fong, J. , Heckert, N. and Filliben, J. (2012), Composites Failure Criteria, Uncertainty Propagation, and Estimation of the A-Basis and B-Basis Design Allowables, Composites Part A-Applied Science and Manufacturing (Accessed November 27, 2024)