A methodology for optimum design of Y-shape noise barriers

Abstract

A method for designing optimum shape Y-noise barriers is performed using a 2D-boundary element method modelling and evolutionary computation. The model assumes an infinite, coherent line source of sound, parallel to an infinite noise barrier of uniform cross section and surface covering along its length, where a maximum limit to the effective height of the barrier designs is imposed. The study is carried out in frequency domain. The proposed fitness function to minimize is the sum of squared differences corresponding to the insertion loss (IL) throughout a set of frequencies belonging to the one-third octave band spectra (fourteen values are taken into account) of two barriers: the candidate Y-barrier design and a reference noise barrier design (a simple barrier with higher effective height than the maximum constrained value of the design). Shape optimization is accomplished by forcing the design to fit a IL reference curve corresponding to a higher effective height simple barrier and to obtain a Y-shape design whose IL curve performance fits this reference. The obtained results succeed in accomplishing the imposed requirements. Results are detailed in terms of IL values and barrier shape designs, numerically and graphically.