Simulation of customized properties in automotive components: GEDIA's FEM approach with TemperBox®
In the context of modern vehicle development, the integration of customized hardening processes is a decisive factor in optimizing crash safety while reducing weight. The TemperBox® technology developed by GEDIA enables the production of press-hardened steel components with locally defined mechanical properties – including martensitically hardened zones, ductile areas, and graduated transition zones. This differentiated material structure places high demands on numerical simulation, especially with regard to the precise mapping of structural behavior under crash loads.
The simulation of customized components is an integral part of the GEDIA product development process, which ranges from function definition and CAD design to validation through physical testing. FEM simulation acts as a link between process-related microstructural changes and structural performance evaluation. In particular, local differences in hardness, yield strength, tensile strength, and failure behavior must be correctly transferred to the simulation model.
To map this complexity, GEDIA has developed two different simulation methods, each tailored to different project phases. The High Accuracy Method is used in the validation phase and is based on detailed input data from the forming simulation, such as thickness distribution, plastic strain, and hardness curves. This data is converted into mechanical parameters using mathematical correlations and assigned at the element level in the FE model. This allows even complex transition areas to be simulated with high accuracy – a decisive advantage for crash analysis.
The second method, known as the Concept Phase Method, is designed for early concept development. It allows rapid iterations, even if complete forming simulations are not yet available. In this case, material assignment is zone-specific, with the component being divided into hard, soft, and transition areas. The mechanical properties are assigned based on typical values. This method offers a good balance between modeling depth and development agility.
Both simulation approaches are validated by quasi-static three-point bending tests and dynamic drop tests. The agreement between simulated and experimental force-displacement curves and failure patterns confirms the high predictive quality of both methods. The High Accuracy Method in particular provides an excellent representation of locally occurring failure mechanisms, while the Concept Phase Method offers a solid basis for concept evaluation.
In addition to technical precision, GEDIA's simulation methodology also offers practical advantages: it allows the design of components with multiple ductile zones, flexible adjustment of the transition width (between 30–70 mm), and reproducible geometry without thermal distortion. TemperBox® technology is also cycle time-neutral and can be easily integrated into existing production lines. Another advantage is the possibility of replacing cost-intensive laser-welded plates with monolithic, tailor-made components.
In summary, GEDIA's simulation strategy for TemperBox® components shows how process simulation, material modeling, and structural mechanics can be successfully combined. The integration of process-specific data into the crash simulation achieves a high degree of prediction accuracy, enabling safe and efficient component design. Tailor-made properties are thus no longer a simulation black box – but a controllable and optimizable design feature of modern vehicle technology.
- Prahel Bhandari, FEM Calculation Advanced Engineering