A COMPLETELY INTEGRATED SYSTEM FOR THE TREATMENT OF CRACK-GROWTH TEST DATA

Abstract

Summary This system for the treatment of crack-growth test data greatly simplifies the huge task of analyzing and managing the experimental data needed for fracture-mechanics calculations. In so doing, the following information is made readily available: (1) via SLURP, a complete log of each test from log-in to completed analysis, all easily accessed as well as sorted by almost any of its identifying features; (2) a permanent fracture-mechanics data library including a versus N data and da/dN versus ΔK data, all accessible, including plots, by entering the specimen number into the SINH program; (3)a computer listing (Fig. 8) generated automatically each month, with every test specimen sorted first by ID number and then a second time by material, operating conditions and specimen geometry; and (4) a completely interpolative crack-growth model which can be used to describe crack-growth behavior everywhere within the bounds of its underlying data base. These special features of the described system make fracture-mechanics amparisons of materials, various test conditions, and material-processing effects all possible within a matter of minutes. With most conventional systems, such comparisons would take days–if the information necessary could be found at all. The described crack-growth dataanalysis system offers an integrated package having all of the desirable features needed to support fracture mechanics testing and analysis. It is simple to access and use and allows for internal checks. It provides repeatable and consistent results quickly, which are stored in a library for easy retrieval. And it provides the analytical interpolative model(s) needed for engine-component life analysis. As a final note, it should be mentioned that although the system described was designed for crack-growth data management, the same approach can be effectively applied to any process involving a large, complex data base. Payoffs in efficiency and accuracy can be realized as with the present crack-growth data system. For example, this approach is currently being considered for use in the Forming and Fabrication area at Pratt and Whitney to assist in the analysis of metal-fabrication methods.