Tunable defect mode in a soft wrinkled bilayer system

Here we study the defect mode in a wrinkled soft bilayer induced by a local geometrical defect introduced into the system. We show that the band gap of the studied composite system depends on the wrinkling-induced stress pattern and is not sensitive to the compression strain ε in the given loading range. However, the frequency of the defect mode apparently varies with ε. This interesting phenomenon enables us to widely tune the spatial extension of the defect mode from highly localized to completely extended by simply controlling the imposed external load. Our strategy to create a tunable defect mode in a soft layered composite is simple and straightforward and may find such broad applications as the development of advanced soft metamaterials and corresponding devices.