Abstract
The remarkable toughening effect resulting from proper combination of three brittle phases in the form of fiber, coating and matrix is a consequence of a particular sequence in the development of damage It is understood that there are both beneficial and detrimental ways for damage to develop; hence, successful design of composites requires the management of the progression of such damage. The conception and design of alternative crack deflecting coating systems is greatly facilitated by, if not dependent upon, understanding such details. In addition, the same damage that is beneficial to toughness in one type of loading may be detrimental to other properties. The development of sufficient understanding of the benefits and penalties is necessary to design such materials with well chosen engineering compromises.
