A nondestructive method for the pretension detection in membrane structures based on nonlinear vibration response to impact

The pretension of building membrane structures may relax over its service lifetime, which may cause engineering failure under external loads. Therefore, the pretension of building membrane structures should be monitored or estimated regularly to compare the actual pretension to its design pretension and then to adopt some strengthening measures to mitigate future problems. Based on the geometrically nonlinear vibration of a rectangular orthotropic membrane structure, a nondestructive detection method for monitoring its pretension is developed in this article. This method is achieved by impacting a low-velocity pellet onto the membrane surface to generate vibration and detecting its response amplitude. Then the detected amplitude is converted into a pretension estimate via a derived formula. In addition, experiments for three kinds of conventional membrane material (Heytex H5573, Xing Yi Da, and ZZF 3010) were carried out according to the theoretical idea. The experimental results proved this method is feasible and verified the theoretical derivation is reasonable.