ETFE foil spring cushion structure and its analytical method

The traditional Ethylene Tetra Fluoro Ethylene (ETFE) foil cushion is in the form of air cushion, whose structural stiffness is offered by the inner air pressure. Because the air supply and control systems are needed, air cushion structures cost extra energy and need much maintenance. In order to overcome the shortcomings of air cushion, the ETFE foil spring cushion that uses a spring to take the place of air pressure is developed in this paper. At first, the analytical method for shape finding analysis and stress analysis of the spring cushion is described in the paper. A numerical example is shown by means of the software package ANSYS and the suggested method so as to verify the validity of the method. Then, a model experiment on the ETFE foil spring cushion is carried out. In the loading test, the compression of spring is recorded and the experimental results are compared with the analytical results. At the end of the paper, an experimental hall using both ETFE foil air cushion units and spring cushion units as its roof structure is introduced. Through the construction and daily use of the experimental hall, the spring cushion system shows advantages such as easier construction, needing no air supply and control equipments, no running energy and little maintenance compared with the air cushion system.