PhD position in Simulation of Thermoplastic Composites Manufacturing for Aerospace Applications
- Enschede, Overijssel
- Tijdelijk
- Voltijds
Press forming is a manufacturing technology for producing small to medium-sized thermoplastic composite components in high volumes. Process simulation software is being developed for virtual optimization of tool design and material handling, enabling first-time-right manufacturing. The predictive quality of these tools relies on accurate constitutive models that describe the behavior of the molten material during forming. With the increasing demand for more complex components, a step change in model accuracy and associated material characterization methods is required.For this purpose, we are looking for two PhD candidates to tackle the rheological characterization and constitutive modelling of molten unidirectionally reinforced thermoplastic composites.Position 1 - Ply and blank bending during hot press forming
Wrinkling is one of the primary process-induced defects in press-formed thermoplastic composite parts. Predicting wrinkling requires accurate constitutive models for the bending behavior of molten reinforced thermoplastic plies, which in turn depends on careful rheological characterization.In this project you will:
- Perform rheological experiments to characterize the bending behavior of molten UD reinforced thermoplastic plies and laminates.
- Develop constitutive models that accurately describe the effects of temperature, bending rate and fiber orientation.
- Implement the developed models in commercial forming simulation software and validate their accuracy against forming experiments.
Excessive friction between the plies in a laminate or between the outer plies and the tool surfaces can lead to defects during hot press forming. Accurate prediction of such defects requires both careful experimental characterization of frictional behavior and advanced constitutive models to describe it.In this project, you will:
- Experimentally characterize ply-ply and tool-ply friction under a variety of processing conditions using our novel improved in-house developed friction tester.
- Critically evaluate earlier developed friction models and extend them to account for effects such as slip direction and temperature dependence.
- Implement the developed models in commercial forming simulation software and validate their accuracy against forming experiments.
Current simulation models do not fully capture the complex, temperature-dependent, anisotropic, and evolving optical and thermal properties of thermoplastic composite materials. In addition, the desired prediction accuracy requires high spatial and temporal resolution, which is time-prohibitive and therefore impractical for large parts. This project therefore aims to develop numerical methods that enable the efficient simulation of the LAFP process while accounting for the aforementioned complexities.In this project, you will:
- Develop and implement a multiscale - both spatial and temporal - numerical framework that enables efficient LAFP process simulations of large structures while still capturing the relevant thermal history with sufficient accuracy.
- Develop and implement an accurate and efficient optical model to calculate the laser heat flux on tape and substrate.
- Couple the two models and validate the result on an industrially relevant part.
Process simulations can provide a cost-effective alternative to determine processing windows as well as to optimize the tooling geometry. These process simulations require efficient numerical algorithms to be practical and to enable robust optimization.Therefore, in this project you will:
- Develop efficient numerical methods and strategies to solve the electromagnetic and heat transfer problem in induction welding.
- Develop constitutive models that capture the temperature dependence of anisotropic electrical conductivity.
- Implement the developed models and validate them against welding experiments.
- A Master's degree in Mechanical Engineering, Aerospace Engineering, Applied Mathematics or equivalent.
- Experimental and theoretical skills in thermoplastic polymers and fiber reinforced composites, experience with polymer rheology is a plus.
- Experience with the finite element method and programming experience in scripting languages like Python or Matlab.
- Good team-working abilities and a positive can-do mentality.
- Proficiency in English, both spoken and written (we require a TOEFL
6.5 score).Additional InformationBenefitsWe offer a full-time 4-year Ph.D. position with a qualifier in the first year; excellent mentorship in a stimulating research environment with excellent facilities; and a personal development program within the Twente Graduate School. It also includes:
- You will receive a gross monthly salary ranging from € 3.059 (first year) to € 3.881 (fourth year).
- Excellent benefits including a holiday allowance of 8% of the gross annual salary, an end-of-year bonus of 8.3%, a solid pension scheme, and 29 vacation days in case of full-time employment.
- A training program, where you and your supervisors will settle a plan for education and supervision.
- Excellent laboratory and support facilities, as well as a diverse team of enthusiastic colleagues and supervisors.
- A green campus with free access to sports facilities and an international scientific community.
- A family-friendly institution that offers parental leave (both paid and unpaid).
- A Curriculum Vitae, including contact information for at least two academic references;
- A cover letter of at most one page. In this cover letter you will indicate your preferred PhD position (only one) and explain why you believe you are the best candidate, while referring to your background knowledge and past experience.
- Transcripts from your Bachelor and/or Master degrees.
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