## LSU Historical Dissertations and Theses

1994

Dissertation

#### Degree Name

Doctor of Philosophy (PhD)

#### Department

Civil and Environmental Engineering

Damage and elasto-plastic analysis is of particular importance to metal matrix composites since the onset of damage and plastic yielding begins very early in the loading process as compared to the composites ultimate strength. Two types of damage models are proposed using micromechanical model. A finite element analysis is presented for quantifying damage and predicting the failure loads of the center-cracked laminate metal matrix composite plates. Both the overall damage model which accounts for all types of damages as a single damage variable and the local damage model which uses the local constitutive damage relations for each of the matrix and the fiber including the interfacial damage between the matrix and the fiber are used in the finite element analysis. In addition to the damage evolution, the development of plastic zones and the stress-strain response are shown for the two types of laminated layups; a ($\pm$45)$\rm\sb{s}$ layup and a (0/90)$\rm\sb{s}$ layup.