A flow curve is important for the accuracy of finite element simulation. However, the stress and strain gained by the uniaxial tensile test are insufficient to characterize the flow curve of sheet metal due to the necking phenomenon. Merklein et al. [1] conducted the layer compression test to obtain the flow curve of the Aluminium alloy sheet. However, a Digital Image Correlation system was used in their study. How can we conduct this test without using the Digital Image Correlation system? Or is there any other test that can gain the flow curve of sheet metal at a large strain?
[1] MERKLEIN M, KUPPERT A. A method for the layer compression test considering the anisotropic material behavior [J]. Int J Mater Form, 2009, 2(S1): 483-6.
You could still conduct a multilayered compression test. You need just a press with an accurate force and displacement measurement system. Sadly you can not apply a lubricant and therefore the height to diameter ratio should be 1.5:1. Additionally you should not trust the flow stress after a logarithmic strain of approximately 0.3, 0.4 or 0.5. The achievable amount of deformation depends on the friction between the layer.
[1] Benrath G, Volles R, Kopp R (2006) Multi-Layer Compression Test under Hot Forming Conditions, steel research int. 77 No.4 p 265-270
[2] Kopp R, Wiegels H (1999) Einführung in die Umformtechnik
if you need the flow curve at high strain rates you should also consider
[3] Kopp R, et al (2001) Flow stress measuring by use of cylindrical compression test and special application to metal forming processes, steel research 72 No.10 p394-401
You could follow the following paper on the test. Strain in two transverse directions need be measured. Assessment on the deformation homogeneity is important for the test.
An, Y.G., Vegter, H., Analytical and experimental study of frictional behavior in through-thickness compression test. Journal of Materials Processing Technology, 2005. 160: p.148–155.
- Badges
- Science topic