On yield surfaces with deformation induced anisotropy
Date Issued
2009
Date
2009
Author(s)
Wu, Kuo-Lun
Abstract
This thesis presents a complete experimental procedure to investigate the yield surface. Specimens made of aluminum alloys of Al7075 and Al6061 were tested under three-dimensional stress (strain) condition. A new definition of proof strain was introduced to determine the yield surface. The experiments of yield surface involve the determination of yield surfaces with different loading path, different control, different pre-strain and the comparison of these yield surfaces. Most experimental result found in the literature consider only two-dimensional yield surfaces. It is a challenge to determine the three-dimensional yield surfaces and it is interesting to find that yield surface rotates in three-dimensional stress space when subjected to pre-torsion.xperiments of fixed-end torsion and free-end torsion with different pre- stress were conducted to investigate the mechanical behavior of Al6061 at large deformation level. Under the condition of free-end torsion, the higher the axial pre-stress is the lower is the shear stress-strain curve, while in the case of fixed-end torsion, a higher axial pre-stress leads to a higher shear stress-strain curve. Both tensile and compressive pre-stresses were investigated.
Subjects
yield surface
large deformation
pre-strain
pre-stress
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-98-R96521203-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):23d2479059d106f51eeaadda1cd2c703