When tackling modern engineering projects, designers must consider not only engineering parameters, but also such key factors as cost, safety, and environmental impact. To exploit the interactions of these various elements, designers must consider them simultaneously. Unfortunately, doing so significantly increases project complexity.

AFRC’s object-oriented optimization tool was used to analyze flutter caused by a “fire pod” mounted under the left wing of the Ikhana unmanned aerial vehicle.
The central executive module allows optimization to take place within each individual tool, in a loop between the executive and the tool, or both. Green denotes fully incorporated tools, yellow indicates in-process tools, and tools marked with red are not yet incorporated.

Innovators at NASA’s Armstrong Flight Research Center (AFRC) have developed software that integrates disciplines to automate the optimization task according to user-defined parameters. In fact, rather than limiting the analysis to a single engineer using one program to optimize one parameter, AFRC’s tool provides a framework that enables several engineers to use multiple programs to globally optimize a model.

AFRC’s object-oriented optimization tool can quickly streamline optimization and design tasks by integrating disparate software packages — NASTRAN®, ZAERO®, Cart3D, FUN3D, MOMAT, etc. — in a cross-platform network environment. During the optimization analysis, designers can convert design variables to structural parameters and generate objective functions using either the built-in pre/postprocessor or their own analyzer.

The heart of the framework is the central executive module, which designers use to choose input/output files and solution modules, determine the status of tasks, and select modules for output viewing and filtering. Instead of relying on one code to perform the analysis for all disciplines, the object-oriented framework integrates the analysis codes for multiple disciplines. As a result, optimization takes place within each individual tool or in a loop between the executive and the tool — or both.

Using just three basic commands, users choose an optimization methodology, provide starting and side constraints for continuous and discrete design variables, and set external file names for interface variables that communicate between the central executive module and each analysis module. Incorporated into the tool are modules that calculate structural weight, stress, deflection, buckling, and more. A graphical user interface can provide a single point of control for applications that run on a user’s PC, or for code that may reside on remote workstations or a computational cluster.

This tool’s automation of design — particularly when applying its MDAO capabilities early in the process — is efficient. Its use of existing tools and practices further saves development time and resources. Furthermore, most of the code is written in standard Fortran programming language; therefore, it is easy to upgrade and incorporate new optimization technologies while integrating/adopting new state-of-the-art software.

The tool was originally developed to enable multidisciplinary optimization in the preliminary design of subsonic, transonic, supersonic, and hypersonic aircraft. AFRC’s innovative MDAO tool also can be applied to other engineering fields, such as shipbuilding, automotive, sporting equipment, packaging, and engineering services.

This work was done by Chan-Gi Pak of Armstrong Flight Research Center. This software is available for use. To request a copy, please visit here.

NASTRAN is a registered trademark of the National Aeronautics and Space Administration.

ZAERO is a registered trademark of ZONA Technology, Inc.