Learning Forum

[Ha heongyu]

Hi there, I am doing stamping forming simulation using LS-DYNA and LS-PrePost.

In LS-PrePost-FLD Tool, to get the graph, there are some input values.

And I want to know if i can change this values and then the fld graph thus obtained is valid.

Originally, there is preset values if run fld tool first, but i have changed some values and i want to know i can do like this when i write paper.

Specifically, I use material "sts304", and as the input value change, the shape of fld graph change.

Then, various graph occurs to one material. It is supposed to do like this?

And if the graph from changed values(from ls-dyna preset values), that values can be set by my own accord or i have to find reference paper?

I tried to find many fld and stamping paper, but failed to clearly find what i want.

And, the reason i want to change the value is, as i think, the fld from preset value does not reflect wrinkling well.

So i changed the values to show the wrinkling well.

So, i will be very appreciated if you let me know if i can changed the fld values(i set the standard such as margin, allowable thinning..) in my own accord or i have to find the reference paper.

[Quanqing Yan]

Hi, from the picture you uploaded it is a graphics problem. For investigation could you please let us know which LSPP version you used and your operation system? You may need update your graphics driver frist see if it can solve the problem.  

[Li Zhang]

Hi heongyu, only the limit curve in FLD is something that's certain and you can use to assess formability. And the best way to get the FLD limit curve is to use experiments to cover the the whole range of strain ratio for the particular steel grade and thickness in concern to generate the limit curve. The marginal zone is usually ("rule of thumb") set as 10% for steel and 8% for aluminum, and it varies from company to company. All other zones are based on user's experience/practice, and individual stampings (part dependent), and they vary from company to company. Hope this helps.