Download di Tesi per l'esame di Ingegneria aerospaziale

Tesi dal titolo Detect of defect in carbon epoxy materials per la cattedra di Ingegneria aerospaziale del professor Carlomagno. This thesis is part of a study aimed at assessing the usefulness of infrared thermography in nondestructive evaluation of carbon/epoxy materials. A main problem of composites is porosity, which may arise from a non-optimal setting of parameters during the curing cycle; it represents a weakness point for materials as it may be the origin of damages during typical loads in service. The main purpose of this work consists in the optimization of the cure cycle of CFRP (Carbon Fiber Reinforced Polymer) samples, realized through the Hand Lay-up production process. Therefore, we tried to identify buried defects and, in particular, the distribution of porosity caused by the cure cycle. Several samples were manufactured with a layering sequence of fibers at 0°, +/- 45° e 90° and by setting the cure pressure in autoclave at different percentage values (0, 25, 75, 100) with respect to the required pressure. A Teflon disk was also enclosed at half thickness to simulate local delamination. Each sample has been submitted to non destructive control with lockin thermography. A MATlab routine has been developed for quantitative estimation of defects.