Tubing process modeling
In general, tube processing is divided to Forming, Welding, Cooling, Sizing, Normalizing, Pickling, Drawing, Cleaning, and Straightening. However, in these steps, Forming, Sizing, Normalizing and Drawing are major ones to affect mechanical properties. Most steps are processed at room temperature (298 K), excepting Normalizing steps which go through increasing temperature for a few minutes. Therefore, considering temperature dependent mechanical properties is significant to obtain more realistic capturing ability.MSU DMG Internal State Variable (ISV) which is a developed material modeling technique has shown an effective capturing ability for mechanical behaviors. ISV's advantage is enhanced by Integrated Computational Materials Engineering (ICME) method. ICME is a multiscale modeling technique and deals with overall scale that is from an electronic scale to a structural scale. Because of this nature, MSU DMG ISV model is able to capture material's history in specific uncertainty range. Therefore, by using this method, one can predict materials' mechanical behaviors in specific mechanical circumstances.
Forming & Sizing
In the case of forming process, raw sheet steel is processed with approximately 20 rollers to form tube-like shape. After welding process, tube shaped material goes through a couple of rollers more to be an appropriate size for next steps.
This is a heating process. From this step, object material is fully annealed, so that the material becomes softened. This process also affects micro-structures of the material. To capture these changes, multiscale modeling is definitely needed. Figure 1 shows a snapshot of a temperature contour on the middle of normalizing simulation.
In the drawing step, tube material is drawn through a drawing bench which is composed of a die and sometimes a mandrel. The tube material that is pulled through the drawing bench becomes thinner and longer. The tube material also have a different mechanical properties and microstructures because of this process. Numerical simulations with ISV model for drawing process is also expected to be able to trace these mechanical changes.