Tolerance Analysis - Key Characteristics Identification by Sensitivity Methods

During the design of manufactured products, functional requirements that need to be fulfilled are defined; they are expressed in terms of the dimensions. Functional requirements are considered as critical if they have a major impact on the performance of the system. In the current industrial practice, the dimensions involved in a critical functional requirement are identified as Key Characteristics. This study aims to rank the influence of the dimensions involved in a critical functional requirement with respect to their impacts on the non-conformity of a mechanical system. This paper presents a methodology for the identification of Key Characteristics by combining the Sobol' global sensitivity method (based on the variance decomposition) with the Advanced Probability-based Tolerance Analysis approach (APTA). The method is applied on an electrical plug having a functional requirement with a linear formulation. The results showed a possibility to prioritize some dimensions and neglect the effect of the others.