Study on Simultaneous Effects of MWCNTs and Cooling Conditions on the Thermal Residual Stresses of Composite Pipes

Abstract

This research focuses on finding Simultaneous effects of addition of multi-walled carbon nanotubes (MWCNTs) and also, various cooling rates on the residual stress components of Thin-Walled Laminated Filament-Wound Composite Pipes, experimentally. To achieve this aim, a few composite pipes were fabricated using the filament winding method with zero and 3Wt% of MWCNTs. Some of these pipes cooled in ambient temperature while the cooling rates of the other were higher. To determine the thermal residual stresses in these pipes, the incremental hole drilling method (IHDM) using integral inverse solution was employed. This method contains simulation and experimental parts, which explained in details completely. A very detailed discussion is delivered that shows by adding MWCNTs to the matrix, residual stresses decrease significantly. As another point, according to the results, the specimen experiences fewer stresses under slow cooling condition compared to the fast cooling condition. Also, adding MWCNTs into the matrix decreases the coefficient of thermal expansions (CTE) mismatch between matrix and fiber and decreases sensitivity about the cooling condition.