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Springback

Summary:

Elastic springback compensation is a long-standing issue for formed sheet automotive components.  The ability to predict the magnitude of springback as a function of material properties and multiaxial multipath plastic strain level would be a key innovation as manufacturers move to advanced, high strength lightweight materials for vehicles.

Description:

Springback, or the elastic change in shape when a part is released from the manufacturing process, has been a problem for decades and accounts for a significant fraction of the expense that the US auto industry spends each year trying out die sets for new body designs.  The inability to predict the magnitude of springback, and thus be able to compensate for it by overdrawing a part, is primarily due to a lack of information about the multiaxial stress-strain properties of metals, particularly when they are deformed along complex, non-linear strain paths.  

(more pending)

Major Accomplishments:

Acceptance of Springback Cup Test by ASTM (ASTM E-2462)

Measurement of through-thickness residual stress profile driving springback in cup test

Lead Organizational Unit:

lightweighting

Staff:

Tim Foecke

Thomas Gnaupel-Herold (NCNR)