Measurement and analysis of the stress distribution during die compaction using neutron diffraction

作者：Wensrich C M^*; Kisi E H; Zhang J F; Kirstein O

来源：Granular Matter, 2012, 14(6): 671-680.

DOI：10.1007/s10035-012-0366-8

• Granular materials
• Die compaction
• Powder metallurgy
• Neutron diffraction
• Powder diffraction

The full axisymmetric stress state of a granular material undergoing compaction in a cylindrical die has been measured using a technique based on neutron powder diffraction. This technique allowed the detailed distribution of stress to be measured in situ, deep within a copper powder inside a solid die. Four components of normal strain were measured over a radial cross section. These components consisted of the axial, radial, hoop and an off-axis strain in the axial-radial direction. This allowed for the reconstruction of the full axisymmetric stress tensor as a distribution over the radial cross section. Many interesting features were observed in this distribution, such as exponential decay of the axial stress (described by Janssen in Zeitschrift des Vereines duetscher Ingenieure 39:1045, 1895), and highly localised regions of high shear stress. The potential of this type of data in the validation of numerical models is discussed.

• 出版日期2012-11