Optimum Design of Thick-Walled Multi-Layered CFRP Pipes to Reduce Process-Induced Residual Stresses

摘要

process-induced residual stresses may cracking inthick-walled multi-layered CFRP pipes during the curing of thepipes, significantly affecting the ultimate structural performance.Several factors influence the amount of the residual stresses, suchas thermal and elastic properties of CFRP, and stacking sequencesand dimensions of pipes. This paper deals with the optimum designof thick-walled multi-layered CFRP pipes by minimising theprocess-induced residual stresses under some constraints ofstructural stiffnesses. An analytic model based on quasi-staticthermoelasticity is adopted for the calculation of the residualstresses in the multi-layered CFRP pipes. The numerical results ofoptimisation show that, in the case of cross-ply pipes, the residualstresses can be reduced to a certain level by controlling plythicknesses. However, in real process conditions, the optimisedpipes are susceptible to cracking because the transverse residualstress is still large in a strength-based sense. To further suppressthe residual stresses, the effects of stacking sequence, wallthickness and axial pre-tension on the optimum solutions are carefully examined.