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A simple evolutionary procedure is proposed for shape and layout optimization of structures with frequency constraints. The structure is modelled with a fine mesh of finite elements plus boundary conditions. It is considered the following hypothesis: small displacements and strains, homogenous and isotropic material. After each eigenvalue solution, a sensitivity number is determined for each element of the structure, so based in this parameter, a number of the elements are removed from the structure. The frequencies of the resulting structure will be shifted towards a desired direction. Several examples are presented to illustrate the options of changing structural frequencies such as: maximizing one or more frequencies simultaneously, maximizing the gap of arbitrary two frequencies

The concerns regarding the future of our planet are incessantly increasing, among which the environmental issue related to the impact of automotive engineering has been discussed more than ever lately. Studies show that the particulate materials and exhaust gases emitted by vehicles put them among the major polluters. Although several attempts have been made and backed by major private enterprises and government departments throughout the world on the development of hybrid electric vehicles, none has ever made it to series production. Hybrid electric vehicles are a very promising solution since they combine the qualities of both the internal combustion engine and the electric motor. Therefore, with a considerable decrease in fuel consumption and its consequent lower emission rate, the hybrid powertrain grants the vehicle a good performance as well as an acceptable driving autonomy.

This paper describes the development of a computational simulation model for internal combustion engines, with spark ignition, powered by ethanol fuel which include the combustion with finite duration, the instantaneous heat transfer and the intake and exhaust processes. The simulation model calculates the thermodynamic properties of each element involved in the process at every discretized instant of the motor cycle using as input the data related to the engine and to its desired operating regime. The simulation model has as a result the temperature and the instantaneous pressure profiles inside of the combustion chamber as a function of the crankshaft angle in the range of one cycle. Besides that, the algorithm includes a variation range of certain parameters of the engine project to evaluate the influence of each one of these parameters in its performance.