EduDIC helps validate new materials for lighter and more environmentally friendly cars

Read how the EduDIC is used by Blekinge Institute of Technology to investigate sheet metal forming and polymer material characteristics for the cars of tomorrow.

At the Structural Mechanics Research Lab with the Department of Mechanical Engineering at the Blekinge Tekniska Högskola (Blekinge Institute of Technology) (BTH) in Sweden, a team of researchers is investigating sheet metal forming and polymer material characteristics in collaboration with the automotive industry.

The benefit for industry is an increase in simulation model accuracy. This accuracy increase can be used for several different aspects, such as validating new and more complex materials, allowing for lighter and more environmentally friendly structures.

Measurements are performed using Digital Image Correlation (DIC) for the evaluation of the impact of cutting clearance in open hole tensile tests as well as, the determination of local strain & strain rate at stable necking of polymer plates under tension.

The advantage of using DIC is that it is the only technique that can be used for the measurement of full-field, principal strains for the detection of strain localization and necking, but more importantly for this application, it is used to accurately measure notched tensile test specimens for the determination of the left-hand side of the Forming Limit Curve (FLC) required, to, allow for comparisons with the full FLC, determined according to ISO 12004.

Figure 1 – 2D-Overlay Visualization of the Eng. Principle Strain 1 (Major Striain) in mstrain. Measurement of a aluminium alloy indicating peak strain is 315 mstrain.

A. Barlo from the Structural Mechanics Research Lab says “the EduDIC is ideal for performing forming limit testing. The system is light and portable and the DIC software, Istra4D, has multiple tools and functions that allow easy setup and calibration, such as automatic projection calibration, focusing optimization, and detailed graphical visualization.
We find the focusing optimization feature very handy for small area strain measurements. Also, the adjustable LED illumination system in the EduDIC package helps to tune lighting for better imaging.
Additionally, a complete DIC Basic User Training course is available to anyone at BTH to use the system and attain a better understanding of the powerful technique of DIC, which allows our students to increase their knowledge faster when they use the system for courses or thesis work.”

Figure 2 – EduDIC system recording deformation images of an open hole tension test in an MTS Qtest100

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