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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

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.