The advanced characterisation techniques and modelling approaches has been used by Estamp to reduce cracking during forming through a more accurate material inputs parametrisation. It permitted to generate a material library for CAE software during forming simulations performed in the phase of tooling design.
The selection of formability material parameters and optimization of part geometries by CAE simulation, has permitted to decrease the monitored non-Quality indicators related with the presence of cracks and to select the correct supplier/material during purchase.
GENERAL OVERVIEW AND DESIGN IMPROVEMENT DURING DESIGN PHASE
One of the most critical points in sheet metals forming is the cracking during production, after the design phase is closed, which means lost money. Within FormPlanet, Estamp has been able to predict in an early stage those cracks, with a more accurate CAE library. All this knowledge help Estamp to understand which parameters affect more their simulations and correlate them with real material tests.
The main conclusions of Estamp work are:
- Estamp can create FLC curves based on Strain-Stress curves, that allow them to save a lot of money (not needed to perform a Nakajima test for each material) and to be confident because it is already checked the correlation between experimental and theoretical FLC’s curves.
- In Al1050 there is a good correlation in FLC’s curves between experimental data (Nakajima test) and Curves created by Estamp.
Good correlation between real Nakajima test (green) and FLC created by Estamp based on new material parameters (red). Source: Estamp
With new material library, the FLC now is more realistic and some areas with cracks and wrinkles are now more representative. Source: Estamp.
FINAL CONCLUSIONS
The correlation observed between a real test for FLC prediction (Nakajima) and analytical FLC creation based on hardening curves make Estamp feel more confident during the CAE material library creation for new materials.
After using this new library database in Estamp during design phase, we have reduced the cost and timing during fine tuning phase and the quantity of rejected materials during mass production.
Next step will be the study of the microstructure size and distribution, to understand how those parameters affect to the material forming.
It can be concluded that the main problem during production comes from the formability of the material, and it is not related to the material fracture toughness.
Marcos Cervantes
Industrial Engineer, Expert in mechanical analysis with a Master’s in CAE simulation and Project management.
Working at Estamp since 2016, Marcos has large experience working as a CAE Engineer and product development and validation. He is currently Head of Product Development in the R&D Department, responsible for product development, material characterisation, thermal, acoustic & mechanical FEM analysis. Marcos is also responsible to carry out product validation, among other things.
