The Materials Mechanics Laboratory (MML) contributes to the development of innovative forming processes and products. MML collaborates with academia, research institutions and industry worldwide to explore innovations in forming technologies. MML focuses its research on advanced high strength steels (AHSS), stainless steels and other materials of interest.

 Compared to traditional drawing quality steels, advanced high strength steels (AHSS) are stronger but more difficult to form into useful shapes for engineered products. The empirical rules that have been used to develop processes and products with traditional steels are no longer valid with AHSS. In sheet forming, critical challenges for AHSS are the wrinkling tendency and springback, which both affect geometrical accuracy, lower achievable stretching strains and reduced drawing depths. Moreover, many products such as fuel cell separators made of stainless steel require tighter dimensional tolerances. Therefore, it is necessary to develop new numerical and experimental tools in order to successfully design innovative forming operations and products.
 
 
 
Yield surface concept representing the plastic behavior of polycrystalline materials (left) and numerical finite element model for simulations of automotive inner hood panel stamping (right)
 
 Although the fine-tuning of a product manufacturing is empirical, modeling is an efficient tool to guide and optimize design. Forming simulations are conducted using commercial finite element codes. One of the main inputs to the simulations is the so-called constitutive description, the mathematical representation of the material behavior. The goal of this numerical approach is to design new process and steel products in a short time by taking advantage of simulation technologies combined with new accurate and efficient constitutive descriptions. The challenge of this research is to develop accurate constitutive models for plastic deformation tailored to new steel generations, yet simple enough to allow time efficient numerical simulations at the scale of real products. Another challenge is to develop advanced mechanical testing, characterization and analysis in order to identify the constitutive parameters.

 The validation of forming simulation results with laboratory scale experiments is necessary. MML is equipped with a direct drive digital servo-press. In this press, each of the two slides is driven by four columns controlled by independent servo-motors. One of the merits of this technology is that, unlike standard equipment, this press is capable of maintaining maximum force during the entire stroke of the slide. Therefore, this press is very effective for deep-drawing processes of high strength steel sheets, which requires higher power compared to traditional steels. In addition, this press can function like a hydraulic press with lower slide velocity and higher accuracy. It is perfectly suitable for research, prototyping and small production trials. The challenge in this technology is to determine the optimum processing paths in a seemingly boundless realm of possibilities. This optimization requires a synergistic interaction with numerical modeling activities.