Structural and Materials Systems Focus

Research in the Center for Aerospace Structures (CAS), one of four centers within the Department of Aerospace Engineering Sciences, is categorized as the Structural and Materials Systems (SMS) focus. The Center is concerned with the analysis and design of complex high-performance materials and structures, predominantly for aeronautical and space applications. This includes the development of innovative computational analysis and design techniques, high-precision experimental methods, and the application of these techniques and methods to novel exciting structural systems.

In the past decade, CAS has gained a world-wide reputation as a leader in the development of analysis and design methods for coupled multi-field problems, in particular in the context of aeroelasticity. The methods pioneered by CAS faculty have become the standard tool in academia and industry for analyzing, for example, complete aircraft using realistic high-fidelity numerical models. This work is complemented by the development of high-performance parallel computing strategies. CAS faculty have led the development of the so-called FETI method, a parallel solver for large scale finite element problems. Today, this approach has been adopted by numerous groups in academia and national laboratories (for example, SANDIA National Laboratories) and is implemented in commercial finite element analysis tools such as ANSYS. In the past years additional focus areas include the development of models and design methods for multi-functional material systems and micro-electromechanical systems (MEMS). The latter two research areas are considered to be key components of next-generation technologies in aerospace, mechanical, and bio-medical engineering, with a large impact on our society.

Another area that CAS faculty have recently been active in is multiscale dynamics of composite materials and structures. This research, which involves analysis, design and computational studies, aims at developing new material and structural concepts for aerospace applications and beyond. For example, novel phononic crystals are being developed for improved vibrations, thermal and strength characteristics

Also housed within CAS is the multidisciplinary analysis and design optimization group which is interested in developing synergistic approaches to the optimization of complex vehicle systems. The disciplines of interest include aerodynamics, aerothermodynamics, propulsion, structures, aeroelasticity, aeroservoelasticity, trajectory, and mission design. Applications for these coupled design techniques range from missiles and atmospheric cruisers to launch vehicles and reentry configurations.

Furthermore, CAS faculty have developed unique approaches for the integration of computational and experimental methods for the design of space structures. This includes advanced system identification methods, experimental instrumentation, and their integration of dynamic data driven software environments. Areas of research and applications range from the nano-scale analysis of friction in joints to large space structures, with sizes up to hundreds of meters. The work on high-precision, deployable space structures (on which CAS faculty are world-leaders) is of great importance to the development of scientific, commercial and military spacecraft.

Figure 1 shows a few results of the research activities illustrating the broadness and relevancy of the research conducted at CAS. For the past decade the analysis and design of military aircraft structures for optimum aerodynamic, aeroelastic, and aero-acoustic performance were one of the main drivers. Figure 1a shows the pressure contours on an F-5 fighter with its pressure signature at the ground. The objective of this research project was to predict and optimize the sonic boom characteristics of supersonic aircraft. The final goal was to design an aircraft that could fly supersonic while generating an acceptable sonic boom at the ground, which is about 5 times lower than the one produced by today's aircraft. Figure 1b shows the initial and optimized geometries of a wing. Using a unique aeroelastic computational frame, CAS faculty optimized simultaneously the aerodynamic and structural performance of the wing. Understanding of complex MDAO interactions for vehicle design is of utmost importance to both NASA and DoD, as shown in the sample vehicle in Figure 1c. This work will lead to better exploitation of coupled vehicle phenomena for improved mission design. This effort is also investigating multi-fidelity approaches for reducing the configuration design/analysis time. In Figure 1d, the optimal design of two 2-layer MEMS structures are shown. Due to limitations of manufacturing techniques only planar MEMS structures can be produced. In order to obtain, however, 3D curved structures one can pattern a typical silicon substrate with gold. This leads to misfit strains which result in spatially curved structures. CAS faculty developed a design optimization procedure to find the optimal layout of the gold patterns yielding a desired deformed shape. This technology can be considered a key to design of novel complex MEMS devices for civil, military, and biomedical applications. Figure 1e shows a composite structure that is designed to passively steer vibrations of different frequencies to different directions. Applications for this system include frequency sensing and vibration isolation.

SMS Faculty:
Carlos Felippa, Professor
Mahmoud Hussein, Assistant Professor
Jean N. Koster, Professor
Kurt Maute, Associate Professor, Smead Fellow
K.C. Park, Professor
Ryan Starkey, Assistant Professor, McAnally Fellow