Engineers in the spotlight: Get to know Stéphane Graff, who represents the many dedicated specialists in thyssenkrupp’s Steel division. He characterizes materials and conducts feasibility studies for hot forming.
- Name: Stéphane Graff
- Age: 37
- Field: Forming simulation
- Process: Characterizing materials and conducting feasibility studies for hot forming
What does simulation involve?
Simulations such as the ones we conduct for sheet metal hot forming can help us fundamentally predict how a steel will react during a hot forming process. In a simulation we virtually reproduce the individual process steps involved in making a component. Each simulation is based on data that describes the material. For example, you need to know what flow properties it has and how it will react under various load conditions and temperatures.
What is special about simulations?
Simulations allow us to answer many questions in the early phase of development. For example: Can we actually produce a component with the planned geometry? Is there a possibility that tears or wrinkles will form during the manufacturing process? If so, does the forming process need to be changed to prevent this from occurring? Simulations can answer all of these questions, and many more. You simulate until you find a solution. Then, you conduct a specific hardware test as part of prototype construction.
What role do you play in this process?
Simulation is based on data and models. When we want to conduct a feasibility analysis for a component, I need to start by preparing a reliable description of the materials. If I do a poor job of preparing this description, the entire evaluation of the forming process will usually be unreliable as well. We examine a material’s characteristics internally or in cooperation with institutes and universities. When we put together feasibility analyses, we need to virtually construct, evaluate, and optimize the individual process steps. This applies for the analyses we provide for our customers as well as for the ones we conduct on internal development projects.
What was the career path that led you to this position?
I am a mechanic. I got my bachelor’s degree in Mechanical Engineering and went on to earn a doctorate in that field. I have been working for thyssenkrupp’s Steel division since 2007, where I primarily focus on sheet metal hot forming. This technology combines mechanics, thermal technology, materials science, and forming technology – that is what makes it so interesting to me.
Where is this process used?
This technology is primarily used in the automotive industry – for all components that need to be made, including hot-formed components. These include structural components that need to protect passengers in the event of a collision, such as A- and B-pillars and bumpers.
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