An Integrated Software Tool for High Fidelity Probabilistic Assessments of Metallic Aero-Engine Components

Abstract

Most current tools and methodologies to predict the life and reliability of fracture critical gas turbine engine components rely on stress intensity factor solutions that assume highly idealized component and crack geometries, and this can lead to highly conservative results in some cases. This paper describes a new integrated methodology to perform these assessments that combines one software tool for creating high fidelity crack growth simulations (FRANC3D) with another software tool for performing probabilistic fatigue crack growth life assessments of turbine engine components (DARWIN). DARWIN employs finite element models of component stresses, while FRANC3D performs automatic adaptive re-meshing of these models to simulate crack growth. Modifications have been performed to both codes to allow them to share and exchange data and to enhance their shared computational capabilities. Most notably, a new methodology was developed to predict the shape evolution and the fatigue lifetime for cracks that are geometrically complex and not easily parameterized by a small number of degrees of freedom. This paper describes the integrated software system and the typical combined work flow, and it shows the results from a number of analyses that demonstrate the significant features of the system.

Modified Method for Surface Probabilistic Risk Assessment of Aero Engine Compressor Disks Considering Shot Peening

“…To further improve engine life, the FAA gradually improved the evaluation of surface defects introduced during the manufacturing and maintenance of life-limited parts, which was approved by the FAA and written in AC33.70-2 [4]. At the same time, The Southwest Research Institute developed the surface hole feature PRA and designed an evaluation tool [5,6]. Since then, the application of the PRA model has been extended to microscopic models of the fatigue cracking of materials [7], simulation algorithms [8], and the influence of residual stress caused by shot peening [9] on the probability of failure of the disks.…”