Importance of uncertainties in non-linear simulation and testing for engineering design

Nowadays, mechanical industries operate in a highly competitive environment, therefore the process of developing a component from concept through detailed CAE and performance validation is optimized for reduced development time and increased product performance. In order to continuously improve the product design and performance, and reduce the costs and time to market, the design and performance engineering is shifted more and more towards virtual modelling and simulation processes from the expensive test-based design evaluations. A second evolution is the booming introduction of active and adaptive systems in mechanical structures, leading to a 'mechatronics systems' revolution to further push the product performance to higher levels, however at the expense of increased system complexity. Here, it is noted that the potential of structural dynamics test and analysis methods for addressing a structural dynamics design assessment or design optimization, depends largely on the confidence that one can have in the results. In this context, a key aspect is to be aware of the key sources of uncertainty in the designed product, and the impact thereof on the product performance. The product nowadays can often no longer be seen as a linear mechanical system, but rather as mechatronics systems and/or as a mechanical system with distinct nonlinear behaviour for certain performance criteria of interest. This paper reviews the main elements of test data and modal modelling uncertainty and assesses the impact of the uncertainty on some typical modelling problems. Some recent methods for uncertainty analysis in modelling are addressed. Examples include a vehicle bumper system analyzed for crashworthiness, the mechatronics system design challenge and structural analysis of vehicle and aeronautics structures.