Revealing and simulating the effect of hidden damage on local and full-field deformation behaviour of cast aluminium
Thursday, June 22, 2023, 8:40 AM - 9:00 AM
Max Bell Theatre
Jakob Olofsson

Pores have been the main focus of quality assurance in castings. Latest research has shown that in aluminium castings pores can form only if there is existing entrainment damage, i.e., pores are merely the visible parts of the entrainment damage, and usually invisible damage is much more extensive. Its effect on deformation behaviour has however not been previously established or observed in-situ. This work applies 2D Digital Image Correlation (DIC) to an in-situ full-field stress-strain analysis of tensile samples with a non-conventional heterogeneous stress distribution. The observations reveal that the effect of hidden damage extends far beyond its impact on fracture behaviour and is responsible for initiating local strain concentrations during deformation. By extracting local stress-strain data, FE simulations are performed to mimic the effect of local hidden damage on the heterogeneous stress-strain field. SEM and FIB-SEM analysis is applied to investigate not only the fracture surface but also a not fractured strain concentration. The combined results show that hidden damage is responsible not only for premature fracture, but also affects the deformation behaviour of tensile samples by introducing dispersed strain concentrations.

Moderated by: Brian Thomas / Laurentiue Nastac