Integration of surface deformations into polytope-based tolerance analysis: Application to an over-constrained mechanism

Polytope-based tolerance analysis has shown a great potential in the Computer Aided Tolerancing (CAT) field. Previous works have considered form defects into this model, which overcomes the drawback of considering toleranced features as surfaces of perfect form. To enrich the capability and applicability of conventional polytope model, this paper further integrates the combined effects of form defects and surface deformations into polytope-based tolerance analysis. Specifically, form defects are considered based on the concept of Skin Model Shapes and surface deformations are calculated based on a Conjugate Gradient Fast Fourier Transform (CG-FFT) method. Thereafter, the polytope-based tolerance analysis is applied to an over-constrained mechanism. With the consideration of non-ideal surface contact status, this new polytope model provides more realistic and accurate analysis results.