Advanced Structural Health Monitoring Solutions for Civil, Geotechnical and Oil & Gas assets
A private company is offering an integrated and innovative monitoring system, based on optical fibre sensors for static and dynamic monitoring of infrastructures. The expertise was originally developed for the VEGA launcher monitoring, during lift-off and pre-launch assembly phases, to enable a detailed analysis on the state of health of the structures, which are subject to significant environmental, vibration, thermal and acoustic stresses.
Structural Health Monitoring (SHM) is an emerging technology that is proving to be very effective in the integrity management of civil and industrial assets because it allows the development of optimized lifecycle approaches. In particular, the use of permanently installed instrumental monitoring systems is growing in many different industries. Asset owners see the benefits of systems able to continuously monitor the state of complex structures, and to provide their characterization, during construction, operation, repair or upgrading phases. The technology donor aims at offering SHM services in civil and industrial engineering fields by exploiting the know-how developed in the Space sector, providing:
- structural integrity monitoring systems for the assessment of loading conditions and safety levels
- on-line management of early warning and alarm signals
- identification of behavioural anomalies and evaluation of their consequences on system reliability, availability and durability
- estimation of the residual life of main/critical structural components
- assessment of the response of a structure under real operational conditions
- Optimisation of Inspection, Maintenance and Repair (IMR) plans. i
In particular, the donor company proposes the implementation of an innovative solution, which meets the need of safety & maintenance aspects of different assets, consisting in the installation of a permanent monitoring system to continuously monitor the asset structural integrity by means of fibre-optic technology which has reached a very high level of technological maturity and provides an effective solution in all market sectors.
According to the application area and the purpose of the SHM, the following services can be developed and offered in the different markets:
- analysis of the structural condition of the Asset
- investigation of the structural behaviour of the system through numerical multi-physics analysis to provide threshold settings
- monitoring system design, through selection and integration of the most appropriate technologies (open approach)
- inspections, surveys, Factory Acceptance Test (FAT), SHM installation, Site Acceptance Test (SAT) and training, system commissioning & maintenance
- data collection, storage, handling and mining
- data validation, visualization and generation of warnings and alarms
- data analysis and processing to provide "operationally relevant information", including anomalies and damage detection
- advanced data analysis and the development and calibration of updated numerical models
Innovations & Advantages
Main benefits of SHM systems:
- enhanced safety level due to early damage detection and warning systems
- better understanding of structure response under operational conditions
- enhancement of the confidence levels when introducing new design solutions, materials or construction processes
- optimization of inspection programs and adoption of a Condition-Based Maintenance (CBM) approach
- validation of structural strengthening phases
- life extension assessment based on monitoring data analysis
In providing personalized and highly specialized monitoring services, the donor company employs both traditional sensors and fibre optic sensors, multi-point (FBG: Fibre Bragg Grating) or distributed ones.
In recent years, fibre-optics technology has reached a very high level of technological maturity and provides an effective solution for applications in the field of diagnostics and structural dynamics, and in particular in the control of components and facilities during construction and operating phases. Indeed fibre optic sensors offer many advantages with respect to the traditional electrical strain and temperature sensors: compact size, high precision and sensitivity, intrinsic long term stability (>30 years), low cost, no electrical conductivity, intrinsic immunity to electric sparks and EMI/RFI, multiplexing and intrinsic chemical stability of glass.
FBG sensors can be applied on a structure with the most suitable technique for reinforcement applications / structural adjustment, or embedding the fibre within the structure during the process of production of the same. The fibre optic sensors, once connectedare able to "read" every deformation and / or vibration of the structure and transmitting this information to the data acquisition systems for a subsequent analysis in order to identify the amount of the deformation and / or the structure vibration characteristics.
Additional benefits of fibre optic sensors technology are reported below:
- Very low signal attenuation over long distances: possibility of remote monitoring;
- Easy installation and cabling: one line to interconnect many sensors placed at various points of the structure;
- Total immunity to electromagnetic interference thanks to the fully dielectric nature;
- Safe even in potentially explosive environments (e.g. mines);
- Stability for long-term measures (years): not required periodic recalibration;
- Wide dynamic range: elongation from 0 up to 1% of the fibre length;
- High resolution: detects small movements of the order of microns and temperature variations with a resolution of 0.1 °C;
- Extremely small dimensions: the fibre core has a diameter of the order of tenth of a millimetre; the complete sheathed sensor has a diameter of few millimetres;
- Chemically inert, therefore can be laid inside of pourable materials (e.g. cement) or laminated (e.g. glass/carbon fibre);
- High robustness (MTBF> 10 million tensile cycles to limit);
- Tens of sensors on a single fibre which also act as a transmission line;
- No junction losses;
- Absence of protruding parts;
- Ease of installation, both in opera and as retrofit.
The donor company proposes to exploit the know-how developed in the frame of VEGA Ground Segment monitoring system and the benefits/added value of fibre optics sensors technology to spread such kind of monitoring solutions in different sectors.
Current and Potential Domains of Application
The donor reached a high level of expertise in this field thanks to the implementation of this work for the VEGA launcher GS (under ESA ESRIN contract n° 21015/07/I/NB). Thanks to this experience, challenging requirements (in terms thermal, vibrational and mechanical requirements) were tested and such expertise may be transferred into different sectors, mainly related to transport and infrastructures, civil engineering, geotechnical and oil & gas.