Mechanics and Failure of Multilayer, Reinforced Membranes

Finite element simulations are used to investigate the mechanical behavior, including the detailed sequence of failure, of single‐and multilayer, fabric‐reinforced membrane systems under in‐plane load. In situ, such membranes are frequently loaded by opening of cracks in the substrates to which they are adhered. Simulations of a “joint‐bridge test,” which produces this type of loading, are carried out. For multi‐ply membranes, characteristic of roofing systems, normal and “inverted” systems are examined. Mechanically, these systems behave quite differently from each other and from their component plies. Simulation of a standard tension test shows that in‐jaw displacements can be significant, and that the mechanisms of load carrying and failure can be quite different from joint‐bridge or in situ behavior. The possible mechanical benefits of an initially debonded strip centered on a substrate joint or crack are also evaluated. The analyses provide an important complement to physical testing.