Finite element analysis for the interface of a respirator and the human face -a pilot study

Comfort assessment of respirator fit plays an important role in the respirator design process and standard development. To reduce the cost and design time of respirators, the design, fit, and evaluation process can be performed in a virtual environment. Literature shows that respirator-induced discomfort relates to stress, area, and region of the face covered. In this work, we investigate the relationship between the strap tensions and the stress and deformation distribution on the interface between the respirator and the headform. This is the first step towards a comprehensive understanding of the contribution of contact stress to the mathematical comfort fit model. The 3D digital models for respirators and headforms have been developed based on 3D scanning point-cloud using a Cyberware^® 3D digitizer. Five digital headform models have been generated: small, medium, large, long and short. We have demonstrated the contact problem between the respirator and the headform by using a large size headform and a respirator model in the ANSYS ^® environment. During finite element analysis, the respirator is "put on" the large size headform model and different strap tensions are applied. In this study, we consider the headform as a rigid body and the respirator to be deformable. The preliminary results show that the strap tensions play a key role in deforming the respirator and the contact stress distribution.