By taking two typical tensile membrane structures as examples, the free vibration
properties of membrane structures were investigated using the Block Lanczos method, and the
effects of stiffness of strengthened cables, prestress on membrane, ratio of rise to span and mass of
membrane were discussed. The results show that the prestress and the mass are the two most
important factors influencing the free vibration properties, and the geometry update resulted from
large deformation has also a great effect on the free vibration properties. Finally, the concept of
mode analysis considering the geometry update was put forward based on the effect of nonlinear large
deformation on geometric stiffness of membrane structures.