Engine Titanium Consortium - Center for Nondestructive Evaluation ...

naturally occurring flaws in forgings. It is recognized that this morphology will be somewhat
different from that in billets due to the deformations that occur in the forging process. Close
contacts will be maintained with the TRMD program to obtain the necessary morphology
information.
Development of the Capability to Make Predictions of the Local POD in Final Forging Shapes:
Because of the complexity of the geometry of final part shape and of the effects of anisotropy
associated with flow lines, the POD will depend strongly on position in final forging shapes. The
new methodology is designed to take these effects into account, and this capability will be
developed and applied. The essential steps that are required will be determinating, on a
point-by-point basis, the following:
• Effect of forged material on the flaw response and noise distributions, building on the results of
the sonic-shaped studies
• Effect of surface curvature and other geometrical parameters on the beam shape and there by
on the flaw response and noise distributions
In parallel, an implementation plan for including these point-by-point variations in the methodology
will be developed, so that the result can be efficiently integrated with the life prediction code,
DARWIN.
Experimental validation will then be undertaken. The ultrasonic response model will be used to
predict the signal response from flaws which are insonified through representative surface
geometries using the samples being developed in Task 1.3.1. Samples will be designed in
cooperation with 1.3.1 to evaluate the full range of surface curvatures typical in final and sonic
shape forgings. Consideration will also be given to evaluation beyond typical curvatures to
determine the limits of the model applicability. The flaw response model will be verified by scanning
these specimens and comparing these observations to the model predictions. Checks on the
resulting POD predictions will be made for certain testing situations for which POD curves have
been estimated by other means (e.g., the ahat vs. a and the R e methods). Upon completion of
these tests, an updated version of the methodology will be prepared.
Improvements/Transfer of the POD/PFA Methodology Software to OEMs: For the new
methodology to have full impact on damage tolerant design and management of rotating
components of aircraft engines, it is necessary that the tools, i.e., software for implementing the
methodology, the associated modules for predicting flaw and noise response as influenced by
anisotropy and geometry, and materials characterization procedures to efficiently use them, be in a
form that can be readily used by the OEMs. These tools will be developed, incorporating the results
of the previously described major work elements. Included will be the methodology software, flaw
and noise response modeling modules (as influenced by anisotropy and part geometry), and
characterization procedures to provide the necessary inputs. As in 3.1.1, numerical approximations
to the predictions of the ultrasonic response models will be developed which are suitable for being
called by the methodology to speed the calculation process to a rate which will be convenient for a
user operating in an interactive mode. Also building on the experiences gained in the Task 3.1.1,
the flaw response models and noise models will be designed to incorporate the effects of
microstructure on beam profile, and hence, on the distribution of flaw response, the effects of tight
Quarterly Report – January 1, 2002 –March 31, 2002
print date/time: 6/6/2002 - 8:39 AM – Page 100