CIVA SHM for guided wave simulation: new developments of damping models and absorbing boundary layers

Abstract

Abstract

Simulation plays an increasing role in industrial applications as it allows to reduce times and costs associated to several tasks, among which design and certification. It is the case in particular for guided wave SHM, for which many parameters may affect the system performances and may be costly to explore. Typical examples are: uncertainties on material parameters and sensors, varying defect positions and geometries, environmental and operational conditions like temperature, static load or sensor aging. Simulation solutions hence need to be fast enough to enable large simulation campaigns, representative of all expected conditions, while showing a good accuracy with respect to the modeled effects. The SHM module of CIVA has been designed for this purpose. It uses a transient high-order spectral element method coupled with a parametric description of the geometry and its features, such as sensors, stiffeners and defects. Relying on the so-called mass lumping method while performing unassembled stiffness operations in parallel, fast computations with low memory consumptions are obtained. Two new features have been added to increase the accuracy of simulation and its computational performances, namely damping models and absorbing boundary layers. Damping models play an important role in accurately predicting the propagated field, in particular for composite materials in guided wave SHM applications. However, they come at an increasing cost. We will show in this presentation three available models, namely Maxwell, Zener and Kelvin-Voigt [1], which may be used based on a trade-off between needed accuracy, knowledge of the damping laws, and computational cost. Validation results will also be presented. In parallel, absorbing boundary layers enable to restrict the size of the simulated domain, thus limiting the computational cost. Indeed, these layers damp waves going outward with a small reflection at the interface between the physical domain and the absorbing one. They hence enable to perform the computations in a limited physical domain without introducing boundary reflections. The length of these layers is chosen automatically based on the wavelengths of the propagating modes. These layers, their associated cost as well as comparisons between simulations with and without them, will be presented. [1] Imperiale, A., Leymarie, N., & Demaldent, E. (2020). Numerical modeling of wave propagation in anisotropic viscoelastic laminated materials in transient regime: Application to modeling ultrasonic testing of composite structures. International Journal for Numerical Methods in Engineering, 121(15), 3300-3338.