Condition monitoring is used to create maintenance strategies and predictive maintenance approaches for industrial machinery and equipment. This typically involves the use of installed sensors to collect data that is then analysed to check for changes in the performance or condition of components. Deviations from the standard parameters can indicate early-stage wear and deterioration, showing not just the current condition of parts but also providing objective data against which to predict their remaining lifespan. This information is used to create maintenance schedules and ascertain when a component needs to be repaired in order to prevent failure.
Condition monitoring plays an important role in preventing unplanned downtimes and unexpected failure as well as for determining the life expectancy of everything from machine components to entire plants.
TWI has been actively involved in the development of condition monitoring solutions for industry for decades, creating new techniques for a range of industries as well as providing support with the implementation of condition monitoring systems for a variety of assets.
One early example of our work to develop new condition monitoring solutions was the creation of acoustic pulsing…
- Acoustic Pulsing - A Condition Monitoring Technique
This large-scale condition monitoring technique that uses acoustic signals that are passed through a structure to a receiver. If the received signal waveform has changed it is indicative of a defect in the structure. This technique was investigated at TWI in the early 1980s to see if it could be used to detect defect growth in large structures such as oil rigs. These tests showed that the system was capable of working with intertransducer distances of tens of metres, and was able to detect defects of a few millimetres in dimension.
However, this was just one example of new techniques tested and developed at TWI…
- Development of a Long Term Creep Monitoring Image Based Technique
The ‘CreepImage’ project involved the development of a new digital image technique for the long-term measurement and monitoring of creep deformation in an engineering structure/component under harsh conditions (high temperature, irradiation etc.). This project sought to find a condition monitoring solution for where direct sensor attachment and human access are difficult or dangerous.
Condition monitoring techniques were also used as part of a project to inspect soil at contaminated sites (‘SOIMON’)…
- New Fast and Reliable Technology for Soil Inspection in Contaminated Sites with Machinery Condition Monitoring
The overall aim of the SOIMON project was to develop an advanced in-situ investigation method for identifying and characterising pollution in contaminated soil. This involved the integration of sophisticated sensors into a solid probe intended to drive down through the soil matrix to perform continuous or semi-continuous measurements. The project developed an in-situ soil sensing system that is deployed in a sonic drill machine. The complete system/ bore pipes were equipped with condition monitoring sensors in order to enhance the time, cost and reliability of the soil monitoring process.
However, much of the condition monitoring work undertaken at TWI involves assisting with solutions for specific industries and applications, each with their own set of challenges. Much of this work was conducted for the wind power industry, where condition monitoring is vital but had been traditionally difficult, costly, and sometimes dangerous.
WIND POWER
The European Commission-funded ‘CMSWind’ project underlined the failure of the then-existing vibration-based condition monitoring systems to detect wind turbine defects before they become critical, instead showing the applicability of condition monitoring systems to enable the prompt detection of defects.
The BladeSave project focused on the problem of fatigue failure and adverse environmental effects on wind turbine blades. Being able to continuously monitor the blades means that defects can be detected and fixed at an early stage, reducing costs and unexpected downtimes. This collaborative project saw our engineers working as part of a wider consortium to use multiple sensing capabilities alongside blade management software to deliver a comprehensive solution for wind turbine blade monitoring, repair and management.
Blade monitoring solutions were combined with systems to assess wind turbine towers and rotating machinery for the CM Project, while the TowerPower project investigated the effective monitoring of the towers and supporting structures of both floating and static offshore wind turbines.
The CM Drive and CMDrive2 projects investigated condition monitoring for wind turbine drive trains using non-contact acoustic sensors in order to address several challenges including sensor installation issues, calibration with manufacturer machinery, and the existing standards at the time.
TWI was also involved in the BIOClean-CMS project to investigate the financial and technical requirements for inspecting offshore wind turbine foundations using guided wave technology, while the NIMO project developed and successfully implemented an integrated condition monitoring system for the continuous evaluation of wind turbines.
TIDAL POWER
Another renewable energy source that was supported by TWI’s expertise was tidal stream power which, despite being environmentally friendly, had been set back by operation and maintenance issues that had left asset availability as low as 25%. The REMO project aimed to address this through the remote, permanent monitoring of the entire frequency spectrum of structural vibrations generated by rotating tidal stream turbine components. The aim was to reduce maintenance costs and downtimes, increasing availability times to around 96%. The TidalSense and TidalSense Demo projects was a European Commission-sponsored project to develop a condition monitoring system for tidal stream generator structures before industrialising the developed sensors and monitoring elements manufactured using modern composite materials, such as fibre metal laminates, honeycombs, glass or carbon fibre reinforced plastics, as well as studying their feasibility as condition monitoring equipment in several tidal energy converters (TEC), including different ones to those used as reference for their design. The projects also included sea trials of the system.
MOORING CHAINS
Also working in a marine environment, our experts have conducted projects related to mooring systems for offshore structures. Primarily used by the oil and gas industry, the failure of these chains can represent a threat to the assets themselves, human life, and the wider environment. As such, considerable effort is made to ensure the integrity of the chains, including through reliable inspection. TWI joined the RIMCAW project to develop robotic inspection of these critical chains in both air and water. This work extended previous project work that saw the development of a tool used by divers to detect critical in-service fatigue cracking, delivering an autonomous robotic system that could travel from the top side of a vessel to subsea and maintain traceability on the condition of a mooring system for the emergence of critical fatigue cracking.
RAILWAY
TWI also has extensive experience of condition monitoring for the rail industry. This ranges from the MONITORAIL project, which developed a wireless, long range condition monitoring solution for rails using guided waves, to the ‘Wirailcom’ project, which investigated solutions for monitoring critical railway vehicle parts such as axles, wheels and bearings. Train doors are also of vital importance for the rail industry as their failure can have serious consequences. The VA-RCM project proposed a vibration analysis-based remote condition monitoring solution for train door control systems, which was designed to automatically detect wear in door rollers, the linear shaft assembly, and ball bearings as well as misalignments in the shaft and door panels before breakdown of the door mechanisms occur.
STORAGE TANKS
Condition monitoring is also important for storage tanks, where corrosion and cracking can have catastrophic effects on the environment. The TIM and Safeast projects involved the investigation of in-situ, long range ultrasonic testing and continuous monitoring of above ground storage tanks respectively. TWI also created a joint industry programme project to assess the performance of non-invasive monitoring of above ground storage tank floors using guided wave monitoring, allowing interested parties the opportunity to provide input into the direction of the research and gain exclusive access to the outcomes.
BRIDGES
The collaborative CROSS-IT project developed new technology, based upon ultrasonic guided waves, for the condition monitoring of concrete structures and steel reinforcements on bridges. The aim was to be able to non-destructively monitor for signs of dangerous age-related degradation caused by water ingress into surface cracks, resulting in corrosion of internal steel re-bars and reinforcement. SmartBridge built upon our earlier research to create smart monitoring and inspection solutions for bridge infrastructures. This involved the creation of an innovative, knowledge-based digital platform to visualise a bridges' condition using virtual models (digital twins), combined with sensor data collected and processed from real bridge infrastructure, incorporating operating environmental conditions and inspection history. The aim was to allow bridge operators to predict failure and plan maintenance before incidents occur, reducing maintenance costs by 20% and downtimes by 60%.
CRANE INSPECTION
Also related to the construction industry was the CRANEInspect project. Funded by the European Commission, this collaborative project aimed to develop an advanced and integrated continuous structural health monitoring system for cranes at industrial, logistics, construction, and shipbuilding sites. The main objectives were to deliver novel non-destructive testing techniques and sensors to inspect for structural damage or cracks in the main frame caused by factors like fatigue, distortion, or corrosion, and to provide real time monitoring information about the condition of the structure.
NUCLEAR
Condition monitoring is perhaps at its most vital when it comes to potentially hazardous environments and those industries where failure could have serious implications. One such example is the nuclear industry, where TWI’s experts assisted a project to develop a radiation-resilient ultrasonic sensor (RRUS). The RRUS project was created to address the issue of inspecting limited access and high thickness components, that are reliant on ultrasonic testing techniques. The radiation endurance of commercially available sensors was limited, leading to severe operational difficulties due to unexpected sensor failure and the time consuming and costly sensor replacement that was required. The RRUS project explored the construction and testing of novel, radiation resilient probes manufactured from exotic materials using a variety of assembly techniques to provide a reliable solution for prolonged inspection and monitoring.
These are just a few examples of condition monitoring research and support provided over the decades at TWI. We continue to provide assistance to our Industrial Members with their condition monitoring needs, delivering independent and impartial support for a wide range of assets and industries.