Forced Response Aeromechanics Analysis in MATLAB®-Based Environment Code With Application to Distortion-Tolerant Fan R24 Blade Geometry

Researchers at the NASA Glenn Research Center have developed a research-level code for forced response analysis for turbomachinery that provides a streamlined framework for aeromechanics analysis,
as well as for generating Goodman diagrams. The Forced Response Aeromechanics Analysis in a
MATLAB-Based Environment (FRAAME, Version 1) code is designed to accept blade surface unsteady pressure time histories generated by three-dimensional (3D) Unsteady Reynolds-Averaged Navier-Stokes
(URANS) code TURBO and modal displacements, modal stresses, and static stresses generated via
expanded ANSYS® (Ansys, Inc.) cyclic symmetry analysis. The code’s looping structure allows for largescale analyses, including many blade surface pressure files, modal displacements, and modal stress files for full annulus forced response analysis, including a modal summation method for multiple engine orders and modes. This code is applied to the R24 fan geometry for the Boundary Layer Ingesting
Inlet/Distortion-Tolerant Fan (BLI2DTF) project, a propulsion system being developed to increase the
fuel efficiency of future aircraft, to serve as validation of experimental data as well as external simulation results.

This tool’s functional, modular form is intended to allow users to make modifications easily. Those
modifications can include requests for information for any step in the analysis process, as well as adding various functions to compute additional information of interest. It is also written, given sufficient input information, as a general blade geometry forced response solver that is not necessarily specific to the R24 geometry but is used here for verification of code functionality and accuracy. Although forced response
analysis tools are also available in commercially available code packages, the post-processing FRAAME
code offers reliable, fast, and scalable forced response analysis and Goodman diagram generation for
large cases utilizing, specifically, TURBO and ANSYS® results information in an effort to streamline forced response and high cycle fatigue analyses.