Local stress analysis of red blood cells in shear flow¹⁾

A three dimensional computational model of fluid-object interaction has been employed in investigation of local stresses during the motion of red blood cells in simple shear flow. The RBC membrane can withstand a finite strain, beyond which it ruptures. The generally accepted threshold value is 4% for the total areal strain. We have designed an in silico experiment where the total areal strain reached 4%. It has been noted previously that locally this value may be much larger with shorter exposure duration. During the simulation, we have analyzed local stresses of the membrane. Besides the areal strain we employed the time of exposure to a certain strain in order to include the possible cumulative damage of the membrane during the process. We have investigated the following two quantities: the maximal local strain and the cumulative load of local strain. We tracked down the locations on the membrane where these quantities reached their maximal values. We suggest that the cumulative load of local areal strain may be an appropriate measure to determine the location where the cell ruptures.