Our study includes fabricating and testing bonded lap joints
with different interface morphologies, along with detailed finite
element modeling. For our experiments (Section 2), we fabricated
standard flat joints as well as joints with two mirror-image zigzag
surface morphologies, and measured the tensile behavior up to
failure. The experiments themselves were not intended to explore
extensive parameter variations, but rather to benchmark and validate the associated finite element (FE) modeling. It was
observed that each kind of non-flat interface morphology displays
a characteristic and explainable load–displacement curve, with an
initial cracking or debonding event, followed by rapid crack
propagation or arrest depending on the interface morphology