Cylindrical Shells of Bimodulus Composite Materials

Certain fiber-reinforced materials, especially those with slightly curved fibers in very soft matrices, exhibit considerably smaller stiffnesses when loaded in compression than when loaded in tension. Examples are tire cord-rubber, wire-reinforced solid propellants, and certain soft biological tissues. For purposes of analysis and design, such materials can be modeled as a bimodulus material, i.e., one having one set of stiffnesses when the fiber direction strain is tensile and another set when this strain is compressive. Using the fiber-governed bimodulus-material model introduced several years ago and verified for cord-rubber composites, the previous work is extended on the deflection of single-layer and cross-ply laminated rectangular plates to circular cylindrical shells of the same construction. A closed-form solution is presented for the case of a simply supported cylindrical panel under sinusoidally distributed loading. Numerical results are presented to show the effect of shell curvature on the neutral-surface position and deflection.