3 dagen geleden - Radboud Universiteit (RU) - Nijmegen
Postdoc Multi-axial Performance of Wrapped Composite Joints
Challenge: Predict interaction of failure modes in composite material and bond under complex load and geometryNovelty: Develop interaction criteria for multi-axial load resistance of wrapped composite jointsBreakthrough: Design and optimisation of bonded wrapped composite joints for steel jackets
- Mekelweg, Delft, Zuid-Holland
- Tijdelijk contract / Tijdelijke opdracht
- Uren per week:
- 36 - 40 uur
- € 2790 - € 4402 per maand
With the increasing size of turbines and the deeper location of wind farms, the monopile foundations of offshore wind turbines increase in size, weight, and costs. Jackets can be an attractive alternative because multi-membered circular hollow section (CHS) support structures are lighter than monopiles. However, the complex welds result in reduced fatigue resistance of structural joints of circular hollow sections, thus higher costs and longer production routes for jackets than for monopiles.
In the project WrapNode-I, TU Delft will lead research with 9 industrial partners that will enable implementation of the innovative, bonded, wrapped composite joint in jackets for offshore wind turbines. We are forming a team of researchers to characterise and understand full-scale and multi-axial behaviour and the influence of the offshore environment on the durability of the joints. The team is led by Dr. Marko Pavlovic, assistant professor of Steel and Composite Structures.
The concept of an innovative bonded joining technology by wrapping composite material (a.k.a. Fibre Reinforced Polymer - FRP) around steel tubes is introduced as an alternative to traditional welded connections. Compared to complex welds, the load is transferred through a dedicated composite wrap and not through the small area of the weld. Fatigue resistance of joints is increased; thus, the tube wall thicknesses of the legs (chords) and brace members can be significantly reduced, resulting in up to 50% lighter jacket structures. In addition, the production time of the jacket is considerably shortened due to the possibility of prefabrication. Compared to monopiles, jackets manufactured with Wrapped Composite Joints offer a potential cost reduction of 25% to 50% for the supporting structures and reduction of CO2 footprint by 30% to 70%.
Your role in the project/team will be to investigate the performance of wrapped composite joints under complex stress state in the root of the composite wrap as a consequence of multi-axial loads (i.e. combination axial and bending) or complex joint geometry such as multi-planar KK-joints.
The research will rely on:
- Component/joint level ultimate failure and cyclic load (fatigue) experiments in Hexapod and custom made load frames
- FEA validation and analysis of failure modes interaction in multi-axial load experiments
- Development of interaction (failure) criterion for multi-axial load behaviour
The project is realised with the support of the Dutch government, GROW consortium and industrial partners: Shell, Tree Composites bv, Siemens Gamesa Renewable Energy bv, HSM bv, Smulders Projects International bv, Enersea bv, AOC Nederland bv, BÜFA composites Benelux bv and Salzgitter Mannesmann Renewables GmbH.
Visit the project's website here.
You will gain scientific experience by working in a dedicated international team of 4-5 PhD and PostDoc researchers at TU Delft. You will develop professional experience by collaborating with a team of engineers from leading industrial partners who will support the project by developing reference full-scale jacket design, design and production of materials and wrapped composite joints specimens.
Background in terms of MSc and PhD in field of (combinations possible):
- Civil/Structural Engineering (e.g. steel structures, connections, composites/FRP structures, tubular CHS or RHS joints)
- Mechanical engineering (e.g. ship building, wind turbine blades, offshore structures, fibreglass pipelines)
- Aerospace Engineering (e.g. composites, fatigue and structural integrity)
- Planning and design of test set-ups and specimen series for component/joint level experiments
- Conducting and control of component/joint level static/cyclic load experiments
- Post-processing and analysis of monotonic and cyclic load experiments
- Non-linear FEA for failure mode and ultimate resistance analysis of structural components/joints
- Writing and publishing scientific papers in top journals
- Fatigue characterisation of composite (FRP) and/or steel structural components/joints
- Fracture analysis of bonded connections/joints
- Failure and fatigue of Circular Hollow Section joints
- Measurement techniques using DIC, LVDTs and strain gauges
- Design and implementation of mechanical fixtures for load application and BC control in component/joint level experiments
- Supervising theses of MSc students
- Teaching in BSc/MSc courses related to steel/composite structures
Duration of contract: 2 years
Salary and benefits are in accordance with the Collective Labour Agreement for Dutch Universities. The TU Delft offers a customisable compensation package, a discount on health insurance and sport memberships, and a monthly work costs contribution. Flexible work schedules can be arranged.
For international applicants we offer the Coming to Delft Service and Partner Career Advice to assist you with your relocation. An International Children's Centre offers childcare and there is an international primary school.
More information about the project can be found here.