Design and fabrication of submerged cylindrical laminates—II. Effect of fiber pre-stress

This is the sequel to the _rst part of this paper "Dvorak et al[\ 0888\ Int[ J[ Solids Structures 25\ 2806 2832#\ concerned with modeling and analysis of laminated composite cylinder fabrication procedures\ such as _lament winding or _ber placement\ which involve _ber pre!stress for waviness reduction as well as overall or local heating to and cooling from matrix curing temperatures[ The _ber pre!stress applied in individual plies is shown to cause a self!stress in the respective plies\ and relaxation stresses in the already completed plies and in the supporting mandrel[ The _nal residual stress state is reached after mandrel removal[ In~uence functions that relate the ply stresses to the applied pre!stress forces are derived[ Direct problems are solved for ply stresses caused by prescribed constant or linearly or parabolically changing pre!stress magnitudes in the layers[ A superposition of the constant and parabolic distributions is shown to lead to nearly uniform stresses through the cylinder wall[ The magnitudes depend on the radial sti}ness of the mandrel that supports the structure during fabrication[ Inverse problems are formulated as nonlinear optimizations and solved by quadratic programming[ The goal is to determine _ber pre!stress distributions through the wall thickness such that the total stresses due to external hydrostatic pressure and _ber pre!stress are as uniform as possible through the wall thickness and con_ned by the ply strength magnitudes