In this program, you will research the influence of voids on the mechanical properties of fibre-reinforced plastics. You can work independently, but a group of other students with closely related topics can support you in evaluation and discussion of results.
Fiber reinforced plastics (e.g. carbon) are materials for future applications in aerospace and automotive industry. Due to their high weight specific strength, stiffness and tailor made properties, they have the potential to increase performance and reaching substantial resource savings. However, the influence of common manufacturing defects is an area of research until today. Especially voids in fiber reinforced plastics influence the strength and fatigue life of composites. Some research indicates possible beneficial or disadvantageous influences on fatigue life and strength.
For this group of future young researchers you are working in a group together with other students, where each of your results will depend on one another. Additionally to a close personal support, a regular bi-weekly meeting will be held, where we can discuss the progress of your work.
The theses within this project are the following:
Single fiber testing.
You test single carbon fibers with a high speed camera setup to obtain the strength distribution.
Development and validation of a micromechanical array of fibers with a void.
You develop a micromechanical testing array with carbon fibers and place a void inside the array. On the produced specimens you perform fatigue tests under the microscope and follow the development of the fatigue crack.
Project thesis/Mini thesis:
Production and testing of compact tension specimen.
In a team of two-three persons you manufacture neat epoxy resin specimens. After cutting the epoxy specimens, they are tested under static and fatigue loading.
Evaluation of the stress state of the micromechanical array of fibers and crack simulation.
With the help of XFEM simulation and the experimental input from the other theses, you evaluate the stress state within the micromechanical array and investigate on beneficial void distributions.
Project thesis/Bachelor thesis/Mini thesis:
Influence of void geometry and void content on the stiffness properties in FRP.
You produce macro-specimens with different void shapes and contents and investigate stiffness and strength properties in different loading directions.
Development of macromechanical specimens with static and fatigue testing.
With the findings of the other theses, you produce specimens that can reproduce the effects of the manufacturing defects on a larger scale and test them under static and fatigue conditions.
Fatigue crack simulation of a fiber reinforced plastic with voids.
With the XFEM method you simulate the fatigue crack growth within a representative volume element. Beneficial void geometries and distributions will be evaluated.
The application for project theses should be done in teams, for bachelor and master theses you can apply individually. Application for the theses is open immediately for students of plastics processing, mechanical engineering, aerospace engineering, automotive engineering and CES (for the simulation theses). We offer you a close support and we expect from you an independent way of working and your interest in fiber reinforced plastics. A conscientious and profound scientific thesis may pay you the way for a further scientific career at our institute. Do not hesitate to contact me.
Fabian Becker, M.Sc. RWTH
Telephone: +49 241 80-27136