A PhD position is available within the framework of the interdisciplinary design projects of the Mechanical Engineering Department at Eindhoven University of Technology. The PhD project will be a combined experimental-numerical study.
Rheology is widely used to determine viscoelastic and flow properties of materials. Sophisticated rheometers have been developed that apply various model flows under well-controlled environmental conditions. The flow conditions are always chosen to obtain simplified stress-strain relations thereby allowing straightforward extraction of the material parameters. However, the experiments are generally extremely costly, require tedious sample handling protocols and operator training. Moreover, characterizing the complete material behaviour over a wide range of flow types and intensities requires combining measurements from different devices. In essence, a rheological measurement is nothing more than “poking” the material somehow, thereby applying a stress or deformation and measuring the response (respectively deformation or stress). From the stress-strain relation, material parameters can then be extracted. The more complex the flow field, the more difficult the inverse problem of extracting material parameters. Nevertheless, a more complex flow field means that intrinsically a much larger wealth of material information is present in the resulting signal. The challenge then becomes to convert this response to actual material parameters.
This design project aims at developing a contactless rheometer that provides flow and viscoelastic properties for materials with a wide spectrum of rheological behaviours. The proposed approach is based on the laser air-puff method, which was initially developed as a firmness test for fruits. In this method, an air puff is applied on the surface of a material and a laser sensor is used to measure the deformation of the surface at the center of the puff. From the extent of deformation, it can be determined whether the material is soft or stiff. In the proposed project, we would like to design a puff-rheometer, which advances the puff technique from a food-texture device to a true rheometer to characterize different rheological material parameters such as viscosity, moduli and yield stress. Thereto, novel image deformation characterization techniques will be coupled with a numerical framework for parameter extraction from viscoelastic fluid flow simulations. Such a contactless measurement that is robust and independent of operator handling as well as intelligent in choosing the deformation conditions has the potential to replace traditional rheometry in various industries or to be used as a non-destructive measurement for precious samples. Realizing this novel rheometer concept requires tackling challenges in different disciplines such as hardware design, image analysis and parameter estimation from viscoelastic flow simulations.
Research Group Polymer Technology
The PhD student will become a member of the Polymer Technology group in the Mechanical Engineering department at Eindhoven University of Technology. There will be co-supervision from and collaborations with the Control Systems Technology group and Power & Flow group, both in the Mechanical Engineering Department at Eindhoven University of Technology. In the Polymer Technology group, our research is aimed at bridging the gap between science and technology in the area of materials processing and design, through the use of experimental and computational tools in the modeling of the full thermo-mechanical history of material (elements) during their formation, processing and final design, to quantitatively predict properties of processed objects. Extensive state-of-the-art experimental facilities for the characterization of mechanical properties in the liquid (rheology) as well as solid (polymer testing) state, combined with microstructure characterization are available. Many of these devices are developed or modified in-house and are therefore unique. The numerical simulation code for viscoelastic fluid flow simulations is in-house developed as well. The group employs a full-time technical staff member with ample experience in equipment design and development.
An overview of the research performed in the Polymer Technology group can be found at:
We are looking for recently graduated, talented and enthusiastic candidates with excellent analytical skills and high grades. The project will require a multi-disciplinary approach and collaboration with a large team of specialists. Therefore, creative problem-solvers with quick learning ability and excellent team-working skills are highly encouraged to apply. A MSc degree (or equivalent) in Mechanical Engineering, Materials Science, Physics or a related discipline is required. Prior experience in experimental rheology, equipment construction, image analysis, numerical simulations of viscoelastic fluid flows or parameter identification is a strong plus. Good English communication skills are required, both written and oral.
Do you recognize yourself in this profile and would you like to know more? Please contact Ruth Cardinaels (R.M.Cardinaels@tue.nl).
We invite you to submit a complete application by using the 'solliciteer nu'-button on this page. The application should include a:
We look forward to your application and will screen it as soon as we have received it. Only complete applications will be considered. Screening will continue until the position has been filled. Starting date of the position is as soon as possible and before the end of 2020.