On the convergence of solid meshes for the prediction of part distortions due to residual stresses

Abstract

Residual stresses in rolled plates, used as raw material for the fabrication of aircraft components, arise from manufacturing processes such as rolling, casting, quenching, stretching, and thermal treatments. After each process, the rolled plate has a geometrically stable condition but with internal stresses. However, during part machining an unbalance in the distribution of residual stresses occurs, in special for aircraft components, due to the large amount of material removal throughout the process. This condition of instability leads to component distortions so that any corrective action affects the manufacturing lead-time and production costs. Part distortions are usually predicted by finite element analyses with linear tetrahedral meshes in which the residual stress profiles are applied as a constant value element-wise. In this work, both linear and quadratic solid meshes are employed to address this problem. For this purpose, a Python-based routine is implemented to apply the residual stress profile at the integration points of the elements. Then, finite element simulations of simple geometric configurations (plates and beams) under theoretical and real residual stress distributions are carried out. Performance and effectiveness of two different meshes—tetrahedral and hexahedral (brick-type)—are checked through comparison with results presented by classical plate and beam theories. A general good correlation for the deflections predicted by them is reached.

A numerical study of the effect of the thickness parameter on machining distortion for aluminum alloy plates

“…In the past, attempts have been made to study the part distortion phenomenon using different techniques [7]. In recent years the trend suggests the use of computational tools, with simulation, provide attractive methods to estimate undesired deformations influenced by residual stresses in components, but also providing complete models that help to understand, from the design stage of mechanical parts and structures, the side effect of part distortion during their machining (recent examples of these can be found in [11][12][13][14][15][16]).…”