The Evaluation of the Spectral Dynamic Stress Intensity Factor by the X-FEM Method Coupled with the Spectral Modal Analysis

In this paper the principal goal is to model cracked structures under dynamic loads by using a new method called the extended finite element method (X-FEM). Then arriving to the evaluation of dynamic stress intensity factor DSIF, which is calculated using two dynamic methods; the first is the modal analysis and the second that is the spectral modal. This latter represents our originality in this study where we want to present its simplicity in the calculation of DSIFs compared to the modal analysis. J integral and Displacement Jump techniques are used to evaluate the modal DSIF and the spectral DSIF.The present study is validated by an example taken from the literature. Next, a case study of a civil engineering structure is carried out in the aim to study the order of crack effect, its size, and its position on the DSIFs and on the dynamic behavior of a concrete structure subjected to seismic excitation. In addition, in order to see the effect of the seismic excitation intensity and the soil support structure, comparison between the spectral stresses intensity factors are tested.