2. Benchmark solution

2.1. Calculation method

The aim here is to estimate the deformation field over the entire structure, based on the deformations measured at a few points on the tube.

To do this, an expansion of the measurement is carried out using the modal expansion technique.

The experimental modes were « simulated » by projecting the numerical modes onto the gauges, in the form of a deformation field at the node.

2.2. Reference quantities and results

It is considered that the technique used is robust if, after expansion of the measurement, it is possible to find the deformation field on all the nodes of the initial numerical model.

The reference quantity is the dot product between the extended field and the field calculated on the initial numerical model. This dot product is obtained by calculating MAC.

2.3. Uncertainties about the solution

The solution obtained is considered correct if the dot product between the extended field and the field calculated directly with the numerical model is close to 1.