Paper number 361
|RESIDUAL STRESS MINIMIZATION TO PREVENT PROCESS-INDUCED DAMAGES IN THICK-WALLED CFRP PIPES|
Eui-Sup Shin and Hideki Sekine
Department of Aeronautics and Space Engineering, Tohoku University
Aramaki-aza-aoba 01, Aoba-ku, Sendai, 980-8579, Japan
|Summary||During the curing process of thick-walled multi-layered CFRP pipes, thermally induced stresses and deformations may cause various damages in the pipes, which naturally affect the ultimate structural performance. In this paper, an optimum design problem for the multi-layered CFRP pipes is formulated by minimizing the process-induced residual stresses under some constraints of structural stiffnesses. The analytic solutions of the residual stresses are obtained based on quasi-static thermoelasticity and Hashin's failure criteria are used for the formation of a strength-based objective function. The numerical results of optimization show that, in the case of cross-ply pipes, the residual stresses can be reduced to a certain level by controlling ply thicknesses. Matrix cracking is the primary damage mode in the thick-walled pipes because the transverse residual stress is relatively large. For angle-ply pipes, it is possible to further suppress the residual stresses by adjusting ply angles. The effects of wall thickness and axial pre-tension on the optimum solutions are also investigated.
||Keywords|| CFRP pipe, process-induced residual stress, optimum design, cross-ply, angle-ply, damage, wall thickness, pre-tension.
Theme : Composite Structures ; Pipes
[ HOME ] [ BACK ]