Vibration isolation of machine foundations by topology optimization of wave barriers

ABSTRACT Vibrations generated from rotary machines can cause problems to the nearby buildings and their residents. Screening the generated waves using barriers is a common solution for mitigating these vibrations. This paper presents a coupled finite element-genetic algorithm methodology to study the efficiency of scattered barriers to alleviate the surface vibrations of machine foundations by focusing on their installation pattern. Additionally, the effect of other parameters including loading frequency of the machine, barrier material, soil layering, and so on is also investigated. The efficacy of these barriers is also compared to the vertical concrete walls, which are easier to be placed in the soil. The results of the analyses showed that using a soft material for the barrier instead of concrete can double the mitigation capacity of the system. Additionally, passive isolation was shown to be the best approach with up to about 27% and 28% vibration reduction in homogeneous and layered soil profiles, respectively. Furthermore, by proper placement, scattered barriers can reduce the vibrations by more than twice as much as the vertical columns. Finally, the optimal pattern at higher frequencies (i.e. 51–60 Hz) was shown to be 10 times as effective as the one at lower frequencies (i.e. 1–10 Hz).