Our Research

Sheet Metal Forming: Pure Bending

Pure bending is a case of bending that is performing with one or both ends of the sheet free. During bending outer fibers of sheet are under tension, while inner fibers are under compression. This form of bending is observed in almost every type of metal forming.

 

Weak deformation e: e = h / (2.r), if r>>h.

Common mode of failure: cracks on the top of the surface. Bendability: B=r/h

Bending and Springback

Large shape recovery or spring back during complex bending operations with aluminum alloys often results in significant problems during componenent assembly operations. Consequently, modeling and characterization of springback behaviour to extend the application of aluminum sheet materials to a large number of automotive componenets has been undertaken. Modeling of sheet forming process has been known to be one of the most cost effective means of optimizing material, part and process characteristics. However, accuracy of the springback prediction depends on incorporation of appropriate constitutive relation in the models.

Bending and springback of automotive
aluminum sheet

 

 

The objective of this research was to identify and develop an appropriate constitutive model for bending and unbending (in combination with stretching) for springback prediction during forming of automotive aluminum sheet materials. Also, the model was validated with relevant experiments such as those shown to simulate a range of realistic sheet forming conditions using well controlled mechanical test systems and a recently acquired instrumented forming press. Once validated, the model was implemented in a general-purpose finite element code to simulate problems of industrial relevance.