Aircraft Structural Modeling In Aero-Mechanical Design

Abstract

Emerging capabilities in commercial design tools promise to significantly improve the multi- and interdisciplinary design and analysis coverage for aerospace mechanical engineers. This paper explores the structural modeling and analysis process for the tail of a small business jet. An example is presented that begins with the detailed design solid models and includes idealized components and powerful new methods for building the structural model. Model assembly and typical solution results are illustrated. The emphasis throughout is on process repeatability and efficiency of incorporating updates as the design team finalizes the aircraft design. I. Introduction ANY aerospace and defense organizations are struggling to knock down silos in support of integrated product development teams (IPDTs). Rapid system development times coupled with the increasingly complex nature of advanced systems require tightly integrated design and analysis capabilities. Multidisciplinary analyses involving thermal, structural, and optical analysis are foundational to spacecraft design, and external aerodynamics and structural analysis to aircraft design. The time required to pass data from discipline to discipline for such studies can no longer be afforded. Integrated tools that automate and assist such multidisciplinary analyses have existed in the form of specialized—and often in-house—developments. This paper explores the emerging capabilities in a commercial tool set that has proven scalability to large detail design projects. This paper continues the first author’s exploration and demonstration of improved tools and process support for the aero-mechanical engineer. Recent papers 2,5 have shown improved process efficiency using two problems: a landing gear door deploying into the airstream, and a two-piece flap driven by a linkage system. These problems included the determination of airloads via an integrated computational fluid dynamics (CFD) analysis and evaluation of mechanical stress, vibration, and multibody dynamics. The current work extends the structural analysis model preparation processes. While the prior examples used computer-aided design (CAD) models as the source for both aerodynamic and mechanical analyses, the models were of modest complexity, which is typical of conceptual design. In the current work, the final design model for a real business jet is used. Techniques for assembly simplification and geometry abstraction are highlighted and the merits of each discussed. The central theme of using a single homogenous tool chain is continued, with an emphasis on helping to simplify and streamline the work activities of the engineer. This is not intended to be an advocacy statement for the example tool set; its use provides an environment in which to explore the interactions of the various disciplines and demonstrate process efficiencies. On the other hand, the intent is not to survey multiple tool sets. The tools presented here are all from the same vendor; this, in the first author's experience, provides significant benefit due to the inherent compatibility and avoids the finger-pointing that so often arises when difficulties occur with the integration of tools from multiple vendors. However, similar capabilities can be assembled using individual tools from multiple vendors. The tools used are from Siemens PLM Software and include brand components known as NX, NX Nastran, and Teamcenter. The NX CAD and computer-aided engineering (CAE) tools are based on the legacy brands UG, I-deas, and TMG, which may be more widely known.