Design and fabrication of submerged cylindrical laminates—I

Abstract

This is the first of a two-part paper concerned with both structural and fabrication process design of a closed-end laminated composite cylinder intended for service in deep sea environment. The cylinder is made of many different orthotropic layers and is loaded by uniform, axisymmetric surface tractions. In addition, piecewise uniform eigenstrains and residual stresses may be caused in the layers during fabrication, by fiber prestress for waviness reduction and by piecewise uniform changes in temperature. The overall goal is to assure efficient use of the composite structure under a prescribed hydrostatic pressure, and to select fiber prestress distribution such that the total stresses in the plies do not exceed certain strength magnitudes. Mechanical and residual stresses in the layers are evaluated with mechanical and transformation influence functions. For the proportional loading applied by a hydrostatic pressure, a procedure is outlined for design of several layups such that the cylinder wall experiences an isotropic in-plane strain and, therefore, all layers support the same compressive normal stresses, regardless of fiber orientation. The results are applied in design and analysis stress fields in a specific structure. Fabrication process design is discussed in the second part of the paper ( Srinivas et al., 1999, Int. J. Solids Structures, 36, 3945–3976) .