Numerical Investigation of Bumps and Oscillation in the Cylindrical Membrane Inflation

Numerical investigation on the fluid structure interaction in the cylindrical membrane inflation is performed by the Euler-Largrangian method. In membrane inflation, the vortex flow and wave system induced by the interaction between compressible jet flow and membrane appeared inside membrane. This phenomenon concentrates the stresses and generates a pair of bumps. The influences of oscillation and bumps on membrane working performance and safety are also investigated.

Modeling Study for the Design of an Innovative Composite Membrane Inflation Test

The focus of this study is to develop a dynamic membrane inflation test to characterize the mechanical response of human corneal and scleral tissues at high rates representative of blast conditions and to model the dynamic loading conditions experienced in ocular blast injuries. Previous studies investigate the quasistatic inflation response of these tissues at pressures in the physiological range (Anderson et al. 2004, Burnstein et al. 1995, Myers et al. 2010, Voorhies 2003). Test data reveals considerable rate-dependence, as both tissues exhibit greater stiffening effects at higher rates.

Constitutive Laws for Biomechanical Modeling of Refractive Surgery

Membrane inflation tests were performed on fresh, intact human corneas using a fiber optic displacement probe to measure the apical displacements. Finite element models of each test were used to identify the material properties for four different constitutive laws commonly used to model corneal refractive surgery. Finite element models of radial keratotomy using the different best-fit constitutive laws were then compared. The results suggest that the nonlinearity in the response of the cornea is material rather than geometric, and that material nonlinearity is important for modeling refractive surgery. It was also found that linear transverse isotropy is incapable of representing the anisotropy that has been experimentally measured by others, and that a hyperelastic law is not suitable for modeling the stiffening response of the cornea.