Improved human-computer interaction for mechanical systems design through augmented strain/stress visualisation

Abstract

Strain/stress evaluation is a crucial operation performed during several stages in the typical mechanical product development/life cycle. However it is often difficult to obtain an appropriate estimation of the strain and stress distribution due to the difficult to model operational conditions, unknown input forces and/or parameters. This makes it particularly difficult for a designer to evaluate whether the final product under testing meets all the operational design specifications. This work presents an extended Kalman filtering approach to obtain accurate strain and stress estimates of a structure under operational loading. This information is exploited in an augmented reality application to visualize strains and corresponding stresses on a real component. This provides a very efficient human-computer interface to evaluate strains and stresses on a physical prototype. This approach is therefore very suitable to improve the design of components due to the good overview of the performance. In order to obtain an efficient formulation, the developed approach is based on the exploitation of reduced order mechanical models based on high fidelity finiteelement design models. By including a parameterization in the reduced model, the approach can be made robust with respect to unknown operational parameters, like boundary conditions. The obtained paradigm is validated on a flexible beam with unknown input forces and length. The proposed approach permits a more natural visualization and interpretation of operational conditions. Our results encourage the adoption of the proposed approach not only for design validation but also on-line monitoring of structural components, opening new possibility in the field of Augmented Reality for Maintenance.