We will present a finite element model for simulating the mechanical behavior of human red blood cells (RBCs, erythrocytes). As the RBC membrane comprises a phospholipid bilayer with an intervening protein network, we propose a discretization of the membrane with two layers of three dimensional advanced solid elements. The characteristics of the very thin lipid bilayer like viscosity and bending resistance are represented by an anisotropic, viscoelastic and incompressible material. The assumption of material anisotropy provides the necessary bending stiffness. Properties of the protein network are modeled with an isotropic hyperelastic third-order material to account for shear elasticity and strain hardening at large deformations. Starting from a flat ellipsoid, we are able to obtain a reference configuration resembling well the shape of a RBC at rest by controlling the surface area and enclosed volume. The numerical model is validated for optical tweezers studies with quasi-static deformations. Results obtained with our proposed membrane model show good agreement with experimental data. The influence of applied constraints and the employed loading conditions can clearly be seen. Further extensions to simulate dynamical experiments including the interaction of the membrane with the cytoplasm, a Newtonian fluid inside the cell, are discussed. The effect of membrane viscosity is covered by the proposed lipid bilayer model.     «

We will present a finite element model for simulating the mechanical behavior of human red blood cells (RBCs, erythrocytes). As the RBC membrane comprises a phospholipid bilayer with an intervening protein network, we propose a discretization of the membrane with two layers of three dimensional advanced solid elements. The characteristics of the very thin lipid bilayer like viscosity and bending resistance are represented by an anisotropic, viscoelastic and incompressible material. The assum...     »