Theses and Dissertations

Issuing Body

Mississippi State University


Lacy, Thomas E.

Committee Member

Bednarcyk, Brett A.

Committee Member

Toghiani, Hossein

Committee Member

Pittman, Charles U.

Committee Member

Sullivan, Rani W.

Date of Degree


Document Type

Graduate Thesis - Open Access


Aerospace Engineering

Degree Name

Master of Science


James Worth Bagley College of Engineering


Department of Aerospace Engineering


A modified Weibull cumulative distribution function, which accounts for the effect of fiber length on the probability of failure, was used to characterize the variation in fiber tensile strength in a SCS-6/ TIMETAL 21S material system and was implemented within the framework of the NASA code MAC/GMC. A parametric study investigating the effect of repeating unit cell architecture and fiber strength distribution on the RUC-averaged ultimate composite strength and failure was performed. Multiscale progressive failure analyses of a tensile dogbone specimen were performed using FEAMAC/ ABAQUS to assess the effect of local variations in fiber strength on the global response. The effect of the RUC architecture, fiber strength distribution, and microscale/ macroscale discretization on the global response was determined. The methodology developed in this work for accounting for statistical variations in microscale properties that feed into macroscale progressive failure analyses can readily be applied to other composite material systems.