1. Introduction

Numerical developments have been carried out in Code_Aster to allow the transitory calculation of structures presenting shock vibrations at certain points. In some cases, frictional forces may also occur and lead to localized wear.

Whether it is damage by pure impact or by impact-friction, the engineer wants to access the quantities associated with this damage, which requires specific post-processing behind the non-linear transient calculation.

This post-processing information is also valuable when one wishes to validate the non-linear calculation module by comparing its results to what can be measured on a specific test bench. Test programs (MASSIF and MULTICHOC) were implemented for this purpose and were the first users of these post-processing functionalities.

The objective of this note is to specify the quantities to be analyzed in shock vibrations and their specificity. It is then a question of determining the appropriate statistical treatments to be applied to these signals in order to identify the most characteristic instantaneous or average quantities.

First, we will see the treatments applied in the case of a problem with shock and friction (option “USURE” of the POST_DYNA_MODA_T command).

The next chapter will be devoted to treatments applied in the case of a pure vibration-impact phenomenon, where the magnitudes of each impact are analyzed more finely (option “IMPACT” of the POST_DYNA_MODA_T command).