A numerical method for studying the effectiveness of polyurethane foam as personal protective equipment material
Abstract
This thesis documents the characterization of flexible polyurethane foam (FPF) to be used as a personal protective equipment material. Polyurethane samples were tested experimentally to calculate the physical properties which were later re-created using a numerical model. A discrete element modeling software was used to generate the geometry to mimic the physical properties of FPF. The pore level numerical model was used to calculate the possible rate of particle penetration for a range (0.2 -200) µm of particle sizes. A parametric study was done using the polyurethane foam parameters to understand the breathing dynamics under steady conditions. The possible particle penetration rate of a facile mask made of flexible polyurethane foam was detailed for different breathing conditions. The results show that a non-medical polyurethane foam mask can drastically reduce the risk of particle penetration for particles larger than 10µm. The process exemplifies a realistic study of facial masks to understand the dynamics and efficiency inside the interested material for any specific particle size and condition. A process to estimate the overall effectiveness of FPF mask when exposed to a cloud of different size particles is also demonstrated. The results indicate that a heavier breathing cycle will create a higher-pressure variation inside the mask surface in a few specific spots through which particles are most likely to penetrate. On the contrary, a normal breathing will create a moderately uniform pressure distribution inside the face mask which will draw in fewer particles when compared to the former cycle.