A propulsion system including a casing surrounding a fan rotor assembly is provided. An example casing includes an outer layer material, an inner layer material including first openings extended partially through the inner layer material along a radial direction of a first side of the inner layer material, and second openings extended partially through the inner layer material along the radial direction of a second side of the inner layer material opposite the first side, and a spring member coupled to the outer layer material and the inner layer material.