Experimental Investigation and Mechanical Model of Tensile Behaviors of Membrane with Seam

The contradiction between the spatial demand of a large-scale membrane structure and the existing membrane processing method encourages the development of membrane splicing technology. However, there has been very limited research on the tensile mechanical properties of the seamed membrane. A detailed experimental investigation of the tensile behavior of polyimide membranes with various seam situations is presented in this paper, including pure membranes and seamed membranes with wide or narrow bond regions. The tensile phenomena, elastic behaviors, fracture performances, and wrinkle configurations of the membrane specimens with different length-to-width aspect ratios are analyzed based on the uniaxial tensile tests and noncontact digital image correlation measuring technology. Furthermore, the analytical models are developed to predict the bond stress distribution and the required minimal seam width. The test results indicated that a seam with a width of 12.5 mm could not provide sufficient bonding force, whereas a seam with a minimum width of 17.6 mm could establish effective seamed membranes. Additionally, the elastic modulus of the seamed region increased 53.5% more than that of the pure membrane using the seam details. The out-of-plane deformation and the number of wrinkles of the seamed membrane specimens are all much greater than those of the corresponding pure membrane specimens for all length-to-width aspect ratios. Moreover, the count of wrinkles can explain the phenomena that the fracture strengths of membranes in group 2 are higher than those in group 1, and there is a slight increase in the fracture strengths of membranes in group 1 with the rise of specimen widths. This principle in this work can be regarded as the basis of the design and application of seams in larger-scale membrane structures.