<div class="htmlview paragraph">A rather general survey of the literature in the fracture mechanics area is presented, covering various failure criteria; available elastic stress analyses applicable for cracks; modifications of the elastic crack analyses that are used to account for limited plastic flow; case of extensive plastic flow; effects of dynamic loading on fracture; fracture arrest, and geometry effects. In addition, some illustrative applications of the principles discussed are carried out to clarify their design implications. A tabulation of energy rates for various configurations is also provided.</div>