Structural Health Monitoring in the Light of Climate Impact and Data Science - Editorial
Authors:   Saarland University, Boller Christian ,   INSA Rouen Normandie, Bareille Olivier 
Published: December 2024

Structural Health Monitoring (SHM) has been now around for several decades. During this period a lot of progress has been achieved, of which a review is worth to be done at this stage of time. SHM sometimes considered to be a sub-set of NDT only, with NDT becoming an integral part of a structure and automating the NDT process in view of maintenance support, is possibly more. It encompasses a variety of other metrological aspects and related evaluation techniques, would those measure the geometry, loads, stresses, strains and possibly further important characteristics of an engineering structure. The information related to all of this can be retrieved through SHM, would this be by numerical simulation or sensing devices applied to the respective structure. What it results into is a description of a structure’s health that allows structural lifecycle management to be performed. The role of NDT in SHM can be seen as the same NDT has within medicine. The role of SHM in engineering looks similar to the role medicine has in life science.

Current SHM solutions become an increasing source of data generation. What this results into is a huge database, which first needs to get organized and the data to be processed and reduced to a representative and manageable size. This might then result into a digital twin allowing a structure’s lifecycle management to become possible. In addition, with today’s monitoring technology and data analysis techniques more information is retrievable than this has been originally possible in the past. Hence, design rules for existing infrastructure could be altered and a structure’s operational capabilities could be enhanced and optimized, would it be in terms of operational life extension, loading or both, all without compromising the structure’s safety, a hidden potential that might be worth taking advantage of.

In this context the 11th European Workshop on SHM (EWSHM) was run in Potsdam/Germany in June 2024 with the ambition to promote the demonstration of SHM applications, to address specific topics relevant in SHM and to make the event also attractive for the younger generation. These targets have been met and an extract of this is presented in this special issue of the Research and Review Journal of NDT (ReJNDT). EWSHM 2024 started with a plenary keynote lecture by Peter Lemke from the Helmholtz Centre for Polar and Marine Research, in which the global warming has been addressed as the greatest challenge in our today’s world in various regards. The motivation of having brought the topic of global warming into the world of SHM has been driven by the fact that an increasing number of our infrastructure is and will further be exposed to the impact of global warming without this infrastructure having been designed for this originally. To avoid compromising structural integrity under conditions like global warming, monitoring in the sense of SHM is a very strong option. The lessons learned from this do become part of an alteration of design rules as mentioned above. This does provide SHM to take over an increasing role and results in the extensive data management mentioned before.

A surprising outcome of EWSHM 2024 has been the high participation of 130 student attendees who mainly presented their research work along the overall 370 presentations made. This encouraged to set up a Best Student Paper Award, where from the student manuscripts provided ten manuscripts were selected by a jury to be the best. The students selected were then invited to further extend their manuscripts before peer review, which allowed them to improve their manuscript at their best including also reviewers’ comments.

The ten student papers finally selected and being presented as a series here do nicely elaborate on these challenges. Following a featured article based on the global warming keynote lecture by Peter Lemke, the series starts with a paper that addresses the effects of a snowmelt-induced landslide on a viaduct by using AI-driven pattern recognition. AI, which principally has a very long tradition in SHM, even when not having been named as such, is also applied in the two papers to follow, which do apply this for damage localization using ultrasonic guided waves as well as an acoustic source in general. Environmental impacts and SHM are also addressed in the fourth paper with respect to vibration monitoring. Hydrogen being one of the most promising energy sources for the future to reduce global warming is a further big challenge with respect to its storage and transport. This is addressed from an SHM point of view in the fifth paper including a way on how to get this linked to a digital twin. The relevance of digital twins and the provision of SHM related thermal data is further elaborated on in the sixth paper, which gives rise to a real application as well. The remaining four papers do address the crucial aspect of data processing and handling, would it be in the context of knowledge transfer between oscillators, the handling of uncertainties in determining eigenfrequencies due to environmental impacts, the enhancement of condition monitoring through operational mode classification or the enhancement of a backscattered guided wave through a meta-lens in the sense of a meta-material.

This broad spectrum of timely SHM related research is provided here to a community being active in NDT and beyond, to see how the interface between NDT and structural engineering can be further enhanced. This is an important aspect, to improve the understanding and to take over the responsibility of the complexity engineering structures are in, would it be with respect to their design, their operation, their economies of scale and even their need for adequate standardization. It is encouraging to see that the younger generation becomes aware of this situation and is taking over this responsibility at its best. The readers of this special issue of ReJNDT are invited to make their own opinion and to possibly even decide, what they would consider as the best of the ten student papers being presented here. Independently a selected jury will do the same to decide which of the papers will finally receive the Best Student Paper Award for EWSHM 2024 and will be able to attend EWSHM 2026 for free to be held in Toulouse/France. Let us hope the initiative having been started here will not break away but rather last for a bright future of SHM.

Christian Boller, Saarland University, Saarbrücken/Germany

Olivier Bareille, INSA Rouen Normandie/France