Track: Design

Abstract

Thin wall parts distort due to redistribution of unbalanced residual stresses after material removal. This distortion is due to generation of bending moment on parts during material removal. Prismatic slender AA2014 models were analyzed by transient thermal analysis and structural analysis with finite element software for geometric distortion against nominal dimensions by incorporating solution treatment properties and then initial stresses and strains into the analysis model for achieving T6 condition. Subsequently, the model was prepared by reducing it to 90% of pre-stresses to simulate stretched model conditions to map with T651 condition. Subsequently, total deformation was analyzed by material removal using birth and death technique for T651 condition models.

Physical experiment was carried out for evaluating residual stresses in a sample by slitting method. With the input of stress from experimental sample, proportional stresses and strains were introduced in the model as correction factor.  Simulation experiments were carried out with corrected model to evaluate total deformation by layer removal.  Deformation results were used for statistical analysis to study the effect of geometrical parameters on distortion trend. It is found that length of the part has significant effect on distortion. This analysis is useful for designing of prismatic slender parts for considering geometry effect on distortion of AA2014 T651, which can be a guide during design for incorporating reinforcements to minimize distortion after material removal.