Guided waves (GW) are of great interest for non-destructive testing (NDT) and structural health monitoring (SHM) of engineering structures such as for oil and gas pipelines, rails, aircraft components, adhesive bonds and possibly much more. Development of a technique based on GWs requires careful understanding obtained through modelling and analysis of wave propagation and mode-damage interaction due to the dispersion and multimodal character of GWs. The Scaled Boundary Finite Element Method (SBFEM) is a suitable numerical approach for this purpose allowing calculation of dispersion curves, mode shapes and GW propagation analysis. In this article, the SBFEM is used to analyse wave propagation in a plate consisting of an isotropic aluminium layer bonded as a hybrid to an anisotropic carbon fibre reinforced plastics layer. This hybrid composite corresponds to one of those considered in a Type III composite pressure vessel used for storing gases, e.g., hydrogen in automotive and aerospace applications. The results show that most of the wave energy can be concentrated in a certain layer depending on the mode used, and by that damage present in this layer can be detected. The results obtained help to understand the wave propagation in multi-layered structures and are important for further development of NDT and SHM for engineering structures consisting of multiple layers.

Simulation has become a prerequisite in engineering and science today for visualization of ideas and concepts. In non-destructive evaluation, simulation is increasingly used to show how an inspection method functions with regard to the component to be inspected and is even used for determining the probability of detection of a respective flaw with regard to the inspection method applied. Probability of detection in non-destructive evaluation is optimized in a way that the best sensor positions, as well as sensor tracking paths, can be found through simulation. In classical non-destructive evaluation, a transducer or transducer array can be virtually moved over the surface of a component to be inspected until a full capture of the component’s surface and hopefully volume is achieved in terms of the inspection process. However, with structural health monitoring, no movement of the transducers is possible in case those become an integral and hence fixed part of the component considered. Determining the optimum position of a respective structural health monitoring transducer network can therefore only be achieved through optimization procedures, where numerical simulation is possibly the only viable solution to get this done. Establishing a numerical simulation platform for structural health monitoring purposes has been the major objective of the recently completed INDEUS (Integration of Non-Destructive Evaluation-based Ultrasonic Simulation) project, which is described in this article. The open simulation platform includes different simulation tools, where the requirements and options for further extension of those tools and different test cases applied for validation so far are described. The target is to even simulate real complex structures such as applied in civil, aeronautical, and other engineering disciplines made of metallic and polymer-based monolithic and composite materials where the digital models are inherited from traditional computer-aided design and finite element–based designs. This lays the ground for determining the probability of damage for a given loading condition and structure, and the propagation of guided waves in the structure considered for an undamaged and a damage tolerant condition. From those simulation results, the determination of an optimum configuration of sensing transducers for a given set of actuating transducers is then shown for a guided wave–based structural health monitoring system solution to be designed allowing the tolerable damage to be detected reliably.

The assessment of metallic materials used in power plants’ piping represents a big challenge due to the thermal transients and the environmental conditions to which they are exposed. At present, a lack of information related to degradation mechanisms in structures and materials is covered by safety factors in its design, and in some cases, the replacement of components is prescribed after a determined period of time without knowledge of the true degree of degradation. In the collaborative project “Microstructure-based assessment of maximum service life of nuclear materials and components exposed to corrosion and fatigue (MibaLeb)”, a methodology for the assessment of materials’ degradation is being developed, which combines the use of NDT techniques for materials characterization, an optimized fatigue lifetime analysis using short time evaluation procedures (STEPs) and numerical simulations. In this investigation, the AISI 347 (X6CrNiNb18-10) is being analyzed at different conditions in order to validate the methodology. Besides microstructural analysis, tensile and fatigue tests, all to characterize the material, a pressurized hot water pipe exposed to a series of flow conditions will be evaluated in terms of full-scale testing as well as prognostic evaluation, where the latter will be based on the materials’ data generated, which should prognose changes in the material’s condition, specifically in a pre-cracked stage. This paper provides an overview of the program, while the more material’s related aspects are presented in the subsequent paper.