Hi
im simulating hydroforming process in abaqus. this process has two major limitations: Bursting and Wrinkling. for bursting criterion, it can be used from FLD (Forming Limit Diagrams) or FLSD in abaqus. But for wrinkling criterion, What do we use ?
Many Thanks.
Dear Hamed,
I am trying to give a answer your problem, pl correct me if i am in the wrong direction. For the wrinkling problem, can't we use drapability limit ( the amount of shear required to cause folds in the material) ?
Thanks.
Yeah. I think we can use it. But, What is the drapability limit? How much is that for materials? How to use it in abaqus?
Dear Hamed,
Drapability limit is a term used in textile engineering. It is the angle to which a normal cloth can be sheared without having folds (wrinkles) in it. In your case also I think it is the folds in the sheet metal. The sheet metal can be modeled as a membrane subjected to lateral converging forces (whose action is like pinching the sheet) which cause the wrinkles.
Pl go thru the link
http://www.textechno.com/index.php/en/fabric-testing-products-77/drapetestl-products-165
Dear Hamed,
I am not sure but I think the FLD and FLSD are used for the prediction of necking instability in sheet metal. Hence, you can use these criteria as the damage initiation criterion then, for predicting the wrinkle effect you may use additional damage model.I think you may write a user subroutine for study the wrinkles deeply.
** The Hill yield criterion with the average Lankford-ratio may be useful to predict the wrinkle phenomenon.
Thank you dear Ali,
but how the Hill yield criterion will be useful to predict Wrinkling?
IF any one have the Abaqus example related to this topic kindly send me
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