Deformed shapes of axisymmetric capsules enclosed by elastic membranes

摘要: A boundary-value problem is formulated describing the shapes of inflated and deflated axisymmetric capsules enclosed by elastic membranes. When membrane tension isotropic principal bending moments obey constitutive equations involving curvatures in reference deformed state but not stretch ratios, capsule shape governed a third-order ordinary differential equation for meridional curvature difference between internal external pressure. Numerical solutions illustrate spherical incompressible membranes biconcave resembling red blood cells. The results demonstrate that solution space consists bifurcating branches arising at sequence transmural pressures, pressure developing inside when certain amount fluid has been injected into, or withdrawn from, interior.