Dimensional and Geometrical Tolerance Analysis of Two Flexible Curved Sheet Metal Parts Assembly

Sheet metal assemblies are widely used in the automobile, aerospace, and shipbuilding industries. Sheet metals deform during the manufacturing and assembly process due to their high flexibility. Traditional tolerance analysis approaches were developed for rigid assemblies; however, new approaches of tolerance analysis and variation simulations have been proposed for flexible (compliant) assemblies using FEM. In this paper, a new method called Interactive Worst Case (IWC) is introduced for tolerance analysis of flexible assemblies, which demands a few FEM simulations and is based on traditional Worst Case (WC) method. IWC method guarantees that all the parts will assemble accurately and have proper function. The case study of this paper is two flexible sheets in the form of quarter cylinders, joined together by six spot welding to form a half-cylinder assembly. The accuracy of IWC is verified by comparing the results to uniform MIC. The results of MIC are also compared to the results of the Monte-Carlo simulation (MCS). 

Keywords:

Assembly Spring-back , Compliant Assembly , Interactive Worst Case Method , Method of Influence Coefficients , Sheet Metal Assembly , Tolerance Analysis