Study on mechanical behavior of adhesively bonded laminated envelope composite joints

The airship exhibits great potential as an aerostat; however, the issue of connection in envelope composites, which serve as the primary structural material, significantly hampers its progress. Here, for the first time, we investigate the potential application of adhesive bonding techniques for connecting envelope composites. Several adhesively bonded joints based on Vectran-based envelope composite are prepared using the hot-pressing method. The obtained adhesively bonded joints exhibit a failure strength of 3.57 MPa, which is more than twice that of the welded envelope composite joints. Then, the mechanical response behaviors of adhesively bonded joints are investigated using mechanical testing, failure morphologies analysis, infrared thermal imaging, digital image correlation technique, and numerical simulation. Experimental results show that the structural parameters (adhesive content, bonding area, and the gauge length of the tested strips) of adhesively bonded joints have a significant impact on mechanical performance. Simulation results show that the stiffness mismatch of the component materials has a negative effect on the failure strength of adhesively bonded joints, which explains why the failure occurs at the fabric interface rather than the adhesive region.