Christopher Jouannet

Abstract: Aircraft design is an inherently multidisciplinary activity that requires different models and tools for various aspects of the design. At Linkoping University a novel design framework is being dev ...

Abstract: The design of modern aircraft requires the integration of multidisciplinary mouels for analysis in the early design phase to increase the chances of a successful project. In this paper, a framework ...

Abstract: In this study the use of a high-order panel code within a framework for aircraft concept design is discussed. The framework is intended to be a multidisciplinary optimization tool to be adopted from the very beginning of the conceptual design phase in order to define and refine the aircraft design, with respect to its aerodynamic, stability and control, structure and basic aircraft systems. The presented work is aimed at developing a module for aerodynamic analysis of concepts as a basis for a direct search optimization of the concept layout. The design criterion, used in the example presented here, is to minimize the maximum take-off weight required to fulfil the mission. Classic and simple equations are used together with the data generated by the panel code solver to calculate the aircraft’s performances. Weights are calculated by means of statistical group weight equations, but the weight could also be calculated from a CAD-model. The design of an Unmanned Combat Air Vehicle is used as test case for three different optimization algorithms: one gradient method based (Fmincon), one non-gradient based (Complex) and one Genetic Algorithm (GA). Comparison of results and performances shows that the Genetic Algorithm is best fitted for the specific problem, having the by far best hit rate, even if it is at a cost of longer computing time. The Complex algorithm requires less iterations and is also able to find the optimum solution, but with a worse hit rate, while Fmincon can not reach to a global optimum. The suggested optimized configuration for the aircraft is very similar to the Boeing X-45C and Northrop Grumman X-47B.

Abstract: Scale effect is of significance in all experimental aerodynamics testing. At high angles of attack such issues as Reynolds and Mach number scaling are further complicated by the presence of complex ...

Abstract: This paper presents the development of a design framework for the initial conceptual design phase. The focus in this project is on a flexible database in XML format, together with close integration ...

Abstract: In the aerospace industry, systems engineering practices have been exercised for years, as a way to turn high-level design objectives into concrete targets on system functionality (e.g. range, noise, and reliability). More difficult is to decompose and clarify sustainability implications in the same way and to compare them against performance-related capabilities already during preliminary design. This article addresses the problem of bringing the important—yet typically high level and complex—sustainability aspects into engineering practices. It proposes a novel integrated model-based method that provides a consistent way of addressing the well-known lack of generic and integrated ways of clarifying both cost and value consequences of sustainability in early phases. It further presents the development and implementation of such approach in two separate case studies conducted in collaboration with a major aero-engine sub-system manufacturer. The first case concerns the assessment of alternative business configurations to maintain scarce materials in closed loops, while the second one concerns the production technology of an aero-engine component. Eventually, this article highlights the learning generated by the development and implementation of these approaches and discusses opportunities for further development of model-based support.

Abstract: This paper examines the desirability and the challenges of incorporating highdelity geometry de nition into the Multidisciplinary Design, Analysis and Optimization (MDAO) process earlier than currently practiced. A major objective is the ability to enable geometry de nition for lowdelity as well as highdelity analyses, in order to support the entire MDAO process from conceptual to detail design in a seamless manner. Another objective is the ability to support di erent disciplines such as both structural and aerodynamic analyses from the same geometry de nition. Finally, there are the goals of ease of use and support for automation to minimize unnecessary or repetitive human e ort. It is argued that Constructive Solid Geometry (CSG) is the natural foundation for attaining these goals. Two di erent current user-level approaches which employ CSG at low level are considered: 1) CAD systems and their \feature" based view of construction, and 2) Bottom-Up methods which generate solid \components". Although Bottom-Up methods do not have the turn-key features of commercial CAD systems, it is clear that their exibility and potential open nature is an advantage in the long term, especially if geometric design-gradient information is required for optimization. To realize the MDAO objectives via the Bottom-Up approach, a new software suite, the Electronic Geometry Aircraft Design System (EGADS), has been developed. It is a relatively simple and compact Open-Source Object-Based API built on top of the extensive OpenCASCADE solid-modeling kernel. EGADS routines implement relatively high-level operations which insulate the user from OpenCASCADE’s size and complexity, and for maximum exibility can be driven by either C, C++, or FORTRAN user applications. The basic features and constructs of EGADS are described, and an example application is presented to demonstrate its capabilities and e ectiveness.

Abstract: This paper presents a formal mathematical framework for the use of the morphological matrix in a computerized conceptual design framework. Within the presented framework, the matrix is quantified so that each solution principle is associated with a set of characteristics such as weight, cost, performance, etc. Selection of individual solutions is modeled with decision variables and an optimization problem is formulated. The applications are the conceptual design of subsystems for an Unmanned Aerial Vehicle and an aircraft fuel transfer system. Both the system models and the mathematical framework are implemented in MS Excel.

Abstract: Aeronautics and astronautics are two closely related disciplines, sometimes found under the joint term aerospace, that have progressed at a formidable pace during the 20th century. Their im...

Abstract: Multidisciplinary design optimization has become a powerful technique to facilitate continuous improvement of complex and multidisciplinary products. Parametric modeling is an essential part with t ...