Introductory remarks.

This philosophy and directions of the DARPA/AFML Interdisciplinary program for Quantitative NDE are reviewed and the structure of this review meeting is summarized. Philosophy of Interdisciplinary Program for Quantitative NDE I would like to make a few, very general, introductory remarks about the philosophy of the Quantitative NDE program and to point out some important features of the meeting this week. The major reason for developing a quantitative NDE capability is so that strengths or lifetimes can be predicted with as high an accuracy as possible. Figure 1 reviews the steps that are required to predict lifetimes in metals under conditions of cyclic fatfgue. The core of the prediction is a failure model, such as fracture mechanics. In order to apply this, one typically needs three types of inputs: environmental considerations, such as stress levels, which are often determined by design; material properties such as toughness, which can be determined from handbooks; and flaw sizes and orientations. Determination of the latter, typically, has been the problem area. That deficiency stimulated the initiation of the Quantitative NDE program several years ago. During this week, the present status of techniques to determine flaw size and orientation, and other input parameters required by specific failure models, will be reviewed.