Volume 6, Issue 10 (November 2009)
Elastic-Plastic Stress Analysis of Cold-Worked Pin-Loaded Holes
A detailed two-dimensional, elastic-plastic finite element analysis of a pin-loaded hole was conducted. A thin rectangular aluminum alloy sheet (7075-T6) with a circular hole was considered under plane stress conditions. The hole was loaded purely by a rigid pin to different load magnitudes. Appropriate contact elements were used at the pin-hole interface to transfer the traction loads from one surface to another. Material nonlinearities for the sheet and friction were included in the analyses. Radial and hoop stress solutions along the pin-hole interface were compared in elastically and plastically loaded holes. The influence of friction on the stress results was studied. The locations and magnitudes of the peak hoop stresses were determined. Lastly, an initial residual field was introduced around the hole by a cold expansion simulation before a subsequent pin-loading analysis. Because the cold expansion process involves some reverse yielding, both isotropic and kinematic material hardening models were considered.