Research On Drilling Technology Of CFRP/Ti Laminate By Embedding Carbon Nanotubes Buckypaper

Carbon Fiber Reinforced Plastic(CFRP)plays a key role in restricting the performance of aircraft,so that improving the strength and structural integrity of composites has become a critical technology in the development of aerospace industry.There are complementary advantages between the hybrid materials,therefore the laminated materials have better structural performance.However,a great danger may emerge due to the fatigue properties of the whole structure,if there is a failure defect in the connecting hole of the laminated materials.It is found that carbon nanotubes buckypaper can be used as a good reinforcement for composite laminates.In order to make high quality connecting holes of CFRP/Ti laminated materials,the methods of improving the interlaminar strength of composites have studied in the thesis.The carbon nanotubes buckypaper has been used to enhance the interlaminar strength,thus the defects(e.g.delamination,burrs)have been reduced and further the hole quality has been effectively improved.Firstly,the structure and properties of carbon nanotubes buckypaper have been analyzed and the preparation methods have been introduced in the thesis.The cutting mechanism of CFRP/Ti laminated material has been described in detail,including drilling and helical milling,and the existing problems and common defects have been analyzed.Secondly,it is shown that the interlaminar mechanical properties of composites can be effectively improved by embedding carbon nanopaper through the comparative experiments of mode I interlaminar fracture toughness,which lays a foundation for hole making experiment.Thirdly,the contrast experiments have been designed and the results have been analyzed.The results show that the laminated material embedded with carbon nanotubes buckypaper can offer higher quality connecting holes.Finally,by comparing with the laminated material with and without buckypaper,the influence of carbon nanotubes buckypaper has been analyzed.It is concluded that the carbon nanotubes buckypaper has a significant improvement for the hole quality through the analysis of the data results and SEM scanning.