Marc Sartor

Load allocation problem for optimal design of aircraft electrical power system

More and more electric systems are embedded in today aircraft. As a result, the complexity of electrical power system design is increasing and the need of generic and efficient design methods is today required. Among numerous design tasks, the allocation of electric systems on the busbars of the electrical power system is considered as an important one since it has a direct impact on the aircraft mass. But due to the high number of possible allocations and regarding the large diversity of potential sizing cases for the equipments, finding the optimal allocation of electric loads is a hard task. In this paper, the problem is formalized mathematically. Then, four stochastic optimization methods are assessed on complex load allocation problems. Based on this assessment, a genetic algorithm using niching method is considered as the most appropriate algorithm for solving this aircraft design problem

Tolerance optimization by modification of Taguchi’s robust design approach and considering performance levels: Application to the design of a cold-expanded bushing

This paper defines a method for the optimization of design parameter tolerances. The general architecture of the proposed method is identical to that of the robust design reference method proposed by Taguchi but its content is different as the tolerances are considered as functions to be maximized here, while Taguchi’s method rather considers these tolerances as fixed data. Instead of looking for design parameters that minimize the sensitivity of some performance criteria, the design parameters are calculated so as to obtain maximal tolerance intervals, thus minimizing manufacturing costs. Performance criteria are then considered in terms of optimization constraints: each criterion gives rise to an inequality constraint that specifies the minimum level of performance that the designer wants to achieve. The possibilities offered by this method are illustrated through its use in the preliminary design of a cold-expanded bushing. In this case, tolerance optimization enables the allowable tolerances on the design diameters to be increased and performance levels are defined on the residual radial stress at the bushing/part contact radius and on the residual orthoradial (hoop) stress at the part inner radius.

Knowledge-based system for aircraft electrical power system reconfiguration

Aircraft electrical power system (EPS), in charge of supplying power to aircraft electric systems, needs a reconfiguration capability in order to overcome cases of EPS component failures. During the design phase, EPS reconfiguration elicitation is a complex task due to the high number of failure combinations and to the aeronautical operational constraints, which are to be taken into account. Therefore a knowledge-based system is developed in order to help designers for such a task. It is based on the implementation of two different types of rules: mandatory and know-how rules. EPS connectivity is managed by graph-theory algorithms. The knowledge-based system is capable of producing several reconfiguration solutions. The knowledge-based system functioning is illustrated in detail on a simplified EPS. Results on an actual and modern EPS are also presented.