Single- and multi-objective shape design of Y-noise barriers using evolutionary computation and boundary elements

The optimum shape design of Y-noise barriers is carried out using single and multi-objective evolutionary algorithms and the Boundary Element Method (BEM). Reduction of noise impact efficiency (using the insertion loss-IL-magnitude) and cost of the barrier (using its total length magnitude) are considered. A two-dimensional problem of sound propagation in the frequency domain is handled, defined by a fixed position emitting source, which pulses in a frequency range, and receptor. A noise barrier (limiting its maximum effective height) is situated between both. Its shape is modified to minimize the receptor measured sound level, which is calculated using BEM. Results of an inverse problem using the IL barrier curve as reference are successfully performed to validate the methodology. The proposed methodology is then used to obtain Y-barriers with 15% and 30% improved IL spectrum. Finally, six non-dominated solutions of the multi-objective optimum design problem are presented in detail. (C) 2009 Elsevier Ltd. All rights reserved.