Analysis and optimization of the chamfered pyramid and evaluation of geometrical parameters' effect on its sound absorption coefficient

Since symmetrical geometry makes it easier to arrange pyramid absorbers on anechoic chamber walls compared to wedge absorbers, the goal of this paper is to present an optimal pyramid-shaped absorber which, in addition to the optimal performance in sound absorption, has other advantages such as less thickness, lower material consumption and cost, easier construction, arrangement and maintenance and occupying less space compared to wedges. The COMSOL Multiphysics software was used to simulate the optimized sound absorber by using the genetic algorithm programed in MATLAB software, with the goal of a 100 Hz cut-off frequency. The results show that the optimized chamfered pyramid at the top performs better at sound absorption compared to the complete pyramid and wedge with 18% less thickness. Furthermore, the cut-off frequency decreased to 91 Hz when a gap of up to 15 mm was created between the adjacent absorbers mounted on the surface, which is desirable.