A corrugation is provided in a polymeric liner configured for inflation against a rigid shape. The polymeric liner has a cylindrical wall with opposing inner and outer surfaces. The liner includes a first liner section having a plurality of annular corrugations. Each of the corrugations has a curved mountain region with a ridge, a curved valley between adjacent spaced apart mountain regions, and a side wall joining each successive mountain region and valley. A distance between successive ridges defines a period of the corrugations. The wall thickness of the liner at the ridge is greater than the wall thickness at the valley. A radial distance between the ridge and the valley defines an amplitude of the corrugations. The amplitude is between about 0.65 times the period and about 0.75 times said period T of the corrugations.