Structural health monitoring in lightweight structures: Fid-Bau Portal

Structural health monitoring in lightweight structures

Hosseini, Seyed M.H. / Duczek, Sascha / Gabbert, Ulrich

In recent years guided ultrasonic waves have become increasingly popular in the non-destructive testing community. Excited and received using piezoelectric transducers they offer the advantage of a possible on-line monitoring during service life. It is a fast developing technology due to its sensitivity to small structural damages, its long range inspection capabilities and the low costs of the required equipment. Therefore, guided wave based structural health monitoring is an interesting methodology for several industries including civil engineering, aerospace engineering and wind energy. In the present study we focus on lightweight materials such as sandwich panels with a cellular core layer. In order to successfully apply guided waves for damage detection purposes the interaction of the wave field with the micro- and macrostructure has to be fully understood. Therefore, parametric studies are conducted deploying the finite element method. Another important aspect why numerical simulations are used is to reduce the experimental measurements that are both time-consuming and costly. In engineering the finite element method is the numerical tool of choice for wave propagation analysis in the time domain. Since a fine spatial as well as temporal discretization is needed an important research area is both seen in developing efficient numerical models (higher order finite elements) and in reducing the model size. One possibility would be to use higher order finite element approaches, such as the spectral element method, the p-version of the finite element method or isogeometric analysis, to increase the accuracy of the simulation. However, the present investigation is focused on a different approach. In the work at hand novel non-reflecting boundary conditions are used to reduce the computational domain. Thus, the number of degrees of freedom is significantly reduced. The proposed non-reflecting boundary conditions - based on dashpot elements - can be easily included in commercial software tools. Therefore, it is possible to simulate the wave propagation without writing your own special needs finite element software. Hence, data to study different damage detection and localization methodologies can be created in no time.