Abstract: The nonlinear strain components of thin shells are the foundations of nonlinear shell mechanics. They are needed in the investigation of various thin shell stability and large displacement problems. Due to the geometrical variety of thin shells we have not seen in existing literatures a complete set of general formulae expressing nonlinearity of shell strain components. In this paper we have derived six of them expressed in Lame coefficients and orthogonal curvilinear coordinates, including both linear and nonlinear parts, three of them are tensile strain components,the other three are shear strain components.

Key words: composite shells, hermetic capsule, free vibration, exact solution