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Technical Paper

Topologic Optimization Applied to an Auxiliary Organs Bracket of an Automotive Engine

The need of mass reduction of automotive engines, aiming at greater performance of the vehicle and cost reductions, demands the research for optimized forms of all its components. The mass minimization of all parts of the engine is not limited only to the optimization of the mechanical project of the part in itself. A part with less weight or volume, saves used material, makes it possible to increase the part production, it facilitates transportation, and, therefore, allows reducing the final cost of the part throughout all its productive chain. In this work the method of Topological Optimization (TO) was applied to project a new geometry, using cast iron, for the alternator and air conditioner compressor bracket of an automotive engine, originally in aluminum. Two geometries had been proposed: one where it is considered manufacture process and another one where it is not considered. The last one was used as step for the optimization of final geometry.
Technical Paper

Paragliders Stability Characteristics

In this paper it is presented an analysis of the longitudinal and lateral-directional stability characteristics of paragliders. The paragliders stability analysis is part of the thesis named “Paragliders Flight Dynamics”, submitted to the Department of Mechanical Engineering of the Federal University of Minas Gerais (UFMG) - Brazil - in partial fulfillment of the requirements to obtain the master's degree in mechanical engineering. The full thesis presents a complete theoretical analysis of paragliders flight dynamics providing useful information for paragliders conceptual design optimization, and representing a first initiative to incentivize the international aeronautical engineering community to dedicate attention to this particular field.
Technical Paper

Sub-optimal control laws for minimization of take-off distance for aircrafts

The present paper presents a method for the numerical determination of control laws for aircrafts needed for optimization of a pre-established maneuver, applied to a take-off under requirements of FAR-Part 23. The methodology is based on the minimization of penalty functions through of mathematical programming algorithms with numerical integration of the aircraft equations of motion. With the optimum control law it is possible to elaborate efficient strategies for automatic flight control and for orientation of piloted flights. Numerical aspects of the application of this procedure are discussed, these being important for their adequate performance. Results are obtained for the optimization of the take-off distance of a tail-wheel airplane and are compared with the take-off distance obtained by manual control.
Technical Paper

Mathematical Modeling for Optimization of Competition Sailplane Flight: a Preliminary Approach

In this work, sailplane symmetrical motion equations including pitch motion controlled by elevator angle are presented. The following effects are especially taken into consideration: i) tail damping due to pitch motion; ii) air density variation according to altitude; iii) presence of vertical and horizontal atmospheric air motions, and iv) non-linearity of CL ′ a curve near stall angle. The mathematical modeling includes the construction of an objective function for competition flight optimization. Making use of the concept of state variables, the minimum time trajectory problem is formulated as an optimal control problem with state constraints. Using simplified control laws and a mathematical programming algorithm, suboptimal trajectories are obtained for the sailplane PIK-20B.
Technical Paper

Flight Path Optimization for Competition Sailplanes through State Variables Parameterization

This paper presents a numerical process for determination of optimal flight paths for competition soaring. The issue is reduction of flight time in order to soar towards an ascending thermal and climb, through thermal flying, to the initial altitude. The optimization procedure consists in the application of a Direct Method in order to obtain suboptimal solutions through parameterization of state variables, unlike a previous study by the same authors which was based on control parameterization. A mathematical programming procedure is used in order to determine the sub-optimal values for the parameterized state variables. The optimal control law, which is necessary for the generation of the sub-optimal state, is obtained through a step by step penalty technique. The obtained results demonstrate that the optimization of transitory phases is important for the minimization of total flight time.
Technical Paper

Optimization of a Cam by a Genetic Algorithm

Using a Simple Genetic Algorithm, the present paper obtains the optimal geometry of a cam with roll follower. In order to evaluate cam performance, an objective function which takes into account the influence of the inertia, the perimeter and of the pressure angle is proposed. The choice for a Genetic Algorithm is justified because, in preliminary tests, the objective function had proven to be multimodal