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Unformatted text preview: forts to propose a coherent information stream and model linking design, production and operation uncertainties and variations. This paper will attempt to do just so in a PLM and multi-disciplinary perspective. This would be the main originality of the proposed work. 1.2. The Jacobian-torsor model The Jacobian-torsor model is basically a matrix equation, relating Functional Requirements (FR) or clearances at the assembly level to Functional Elements (FE) or tolerances at the part level. This is done using a simple matrix product with a Jacobian (J) expressing the geometrical relation of the FE with respect to the FR (equation (1)). [FR] = [J][FEs] (1) In mathematical terms, FE and FR are represented as torsors, with their respective components being bounded by intervals, according to the size of the corresponding uncertainty zone (tolerance or clearance). This is shown in equation (2), where the terms of equation (1) are expressed with the interval formulation. Additionally, Functional Elements can relate surfaces belonging either to the same part or to two distinct parts establishing a contact or a play (fit or gap). In the first case, the FE is said to represent an internal pair, whereas in the second instance, it expresses a kinematic pair. In both cases, however, the mathem...
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- Spring '10
- The Land