PhD Thesis Colloquium: Mr. Rishi Raj (14/10/24)
Thesis title:
Advanced thermoplastic laminates with tailored interface for aerostructures
Faculty advisor(s):
Prof. Subodh Kumar and Prof. Suryasarathi Bose
When?
14th October, 2024 (Monday), 3:00 PM (India Standard Time)
Where
KPA Auditorium, Department of Materials Engineering
Abstract:
Carbon fiber reinforced polymer (CFRP) laminates are currently used in commercial aircrafts replacing their metallic counterparts. Epoxy is used as matrix in CFRPs in the primary structures of aircrafts such as fuselage, wings and tail parts, due to its superior properties. However, there are many disadvantages in CF/Epoxy laminates such as, slow production rate due to curing, lack of recyclability, brittleness, and susceptibility to catastrophic failure. Additionally, epoxy requires rivets for joining, have a limited pot life, and pose challenges in damage repair. Their sensitivity to high temperatures also restricts their use in applications near engine components. To overcome these problems, high temperature thermoplastics such as PEEK can be used instead of epoxy as matrix. It does not require curing and the presence of phenyl groups in the main backbone chain provides high strength, thermal stability and rigidity to the polymer, and it can be used at high temperatures (150-200oC) for prolonged time without losing structural integrity. However, the surface energy of CF and PEEK are very different. The lack of functional groups and smooth surface of CF increases the difficulty in wetting of PEEK over CF. The poor interface between PEEK and CF will give rise to poor mechanical properties such as interlaminar shear strength (ILSS), Flexural strength (FS), fracture toughness etc. This thesis endeavors to achieve good mechanical as well as functional properties such as, deicing and electromagnetic shielding, and contributes to enhance the current knowledge in CF/PEEK laminates. These properties are highly desirable to perform as a better aerostructural material in the current scenario. It also explores the damage aspects and recovering the properties after damage.