| The purpose of this thesis is to study the damage zone of pre-cracked plate by using the Yeh-Stratton failure criterion and quadric surfaces criterion under tensile stress condition. To investigate these criteria, the influence of the material properties, crack angle, and fiber orientation was studied. Special emphasis was placed on defining the shape of the damage zone. The results from the Yeh-Stratton criterion and quadric surfaces criterion for both isotropic materials and fiber-reinforced were compared with several other fracture criteria.; The results of this study indicate that the Yeh-Stratton criterion always yields bigger damage zone than the other failure criteria. It is more conservative and will probably be recommended as a proper engineering design and practical repair guideline. Meanwhile, the quadric surfaces criterion has its unique feature in application without the determination of interaction terms. |
