Die-face compensation algorithm in stretch forming of aircraft skin over reconfigurable compliant tooling

Two finite element models of a single curvature part, discrete and equivalent models of stretch forming over reconfigurable compliant tooling, were set up. The calculation times, rubber deformations and part shapes in two models were compared. The result shows the equivalent model is reliable and more efficient. To eliminate the influence of springback and the interpolator deformation on the part shape fidelity, a die-face compensation algorithm was proposed based on displacement adjustment method and equivalent model. In the algorithm springback compensation and deformation compensation of interpolator were performed in sequence. This algorithm was applied to compensate the die-faces of a single curvature part and a double curvature part. Finally, the two parts were stretch-formed over compensated die-faces and measured by non-contact three-dimensional measurement techniques. The results show that the shape errors are both within tolerance (±0.5 mm) and meet the requirements. It is proved that the algorithm is effective.