Turbine Blades
ZF Wind Power; Improving the gear load carrying capacity and noise performance
In wind turbine drivetrains, using Romax Enduro in a simulation-led design process verified by physical correlation, the company gained high ratio of benefit
“Romax Enduro is helping us to tackle the current challenges faced by the wind market. We are able to create a virtual representation of the gear system and the test environment. This means, firstly, that we can fine tune our micro geometry to achieve an optimized load distribution on the gear flank and in the gear root over a wide torque range, and, secondly, that we can detect noise risks early in the design process and identify design measures to mitigate those risks.” Nico De Bie, Gears Excitation Engineer at ZF Wind Power ZF Group have production, development, sales andservice sites worldwide, with 271 locations and 153,000 employees in over 42 countries. They have divisions focusing on Mobility (eMobility, commercial vehicles, car chassis and powertrain, safety systems) and on Industrial Technology (aviation, marine, off-highway, mining, and wind power).
The Wind Power business unit is founded on some of the richest wind turbine driveline experience of the 20th century, combining ZF (founded in 1915), Hansen transmissions (active since 1923, acquired by ZF in 2011), and the large gearbox department from Bosch Rexroth Wind (started in 1920, acquired by ZF in 2015). Based on this strong background, ZF Wind’s portfolio covers the total wind market, with products ranging from 2.xMW to 10.xMW, developed for both onshore and offshore applications. Much of the production process is inhouse, from gear manufacturing to heat treatment, high precision machining of the castings, quality assurance, and test rig facilities (with a maximum testing capability of 13.2MW).
ZF Wind Power started using Romax software over 10 years ago, initially to simulate roller bearings within a flexible model to determine the optimum clearance settings for contact stress and life. Nico De Bie, Gears Excitation Engineer at ZF Wind Power, explains, “Although bearing calculations were our initial reason for using Romax software, we have more recently expanded our use of Romax Enduro to further explore gear modelling and design options at the drivetrain level, for example multiple planet systems, drivetrain dynamic behaviour, gear micro-geometry design, root stress analysis and estimating gear excitation.”
Reducing the cost of energy and minimising noise As the wind turbine market grows to meet the demands of global sustainability initiatives, manufacturers are constantly pushing for higher power generation capacity at lower unit cost. To achieve this, significant steps have been made over the last decade regarding weight reduction and torque density increase, although there is still a great deal of work to be done. De Bie comments “The wind market is facing critical challenges. We are looking to reduce the cost of energy, in part by decreasing the amount of materials used and reducing the overall size of the turbine parts. Wind turbine OEMs are also looking to extend the potential wind areas, both by expanding their range in ‘high wind’ zones and by exploring new ‘low wind’ zones.”
As zones increase and turbines shift closer to residential areas, low noise is critical in order to minimise disturbance.
Since the largest portion of wind turbine noise is generated by the rotating blades, decreasing the sound is generally achieved by blade redesign and noise-reduced operating modes e.g. reducing rotor speed at night. However, it is not only the blades which emit noise. Vibrations from the gear unit or generator are transferred towards the turbine structure and can be emitted as noise via the blades, tower or nacelle. This mechanical noise is typically tonal in behaviour, meaning it stands out from that of the blades. As a result, manufacturers are under pressure to minimise gear excitations, aiming to achieve ‘tonal free’ wind turbines.
Top: Planetary gear stage design modelled in Romax Enduro; Bottom: Correlation of root strain values against mesh width of the sun (left) andring (right) gears, showing measurement vs simulation at varying load levels
De Bie comments: “To face these challenges, we need to reduce the sound power level, and, critically, develop power dense, perhaps non-conventional designs, at smaller weight and delivering higher torque. Romax Enduro is a key part of helping us meet these demands.” In the following sections, ZF share several examples of how they use Romax Enduro to meet the demands of the wind industry.
Increasing gear load carrying capacity The first example is a conventional planetary gear stage design. ZF built a simple Romax model, with a grounded ring gear and no finite element (FE) housings, and compared the load patterns and root strain results from Romax Enduro with their measurements (see below). De Bie comments: “The Romax gear contact model results in realistic flank stress distributions considering system deflections, local component deformations and gear topologies under varying load conditions. There is very good correlation between our gear load measurement and simulation in Romax Enduro. Since Romax considers system load dependency, the mesh misalignment also matches the test rig value well. These results gave us confidence in the simulation model. Having this kind of simulation of the gear stage allows us to further optimise the gear topology definition.”
Using the Romax simulation, ZF were able to decrease the load distribution factors for this design significantly over the entire load range. This leads to improved load carrying capacity of the gear stage, which, as De Bie suggests, can have multiple benefits: “We have two options here. Either, we can decrease the total component width, i.e. reducing materials and cost, or we can expect the gear unit will be able to cope with higher load demands throughout the lifetime of the product.” However, despite this improvement for durability, ZF still had challenges with the tonality, so used Romax Enduro’s Gearbox Transmission Error (TE) functionality to explore and mitigate the noise risk. The graph below shows correlation of measured TE with the Romax simulation. “The TE correlation shows a good match in both shape and amplitude,” De Bie comments. “This is especially impressive considering the model is hugely simplified. To save time, we do not account for gravity in the simulation – this means we only need to calculate a single tooth pass, rather than an entire planetary rotation. Additionally, we were using an ideal topology, not accounting for production deviations, and only modelled a single gear stage. Our test rig set-up also has imperfections – we are doing back-to-back testing, there are vibrations in the environment, we have limitations regarding the sensor positioning, stiffness of the sensor brackets, the accuracy of the sensor, and the speed and torque conditions. In light of these simplifications in our modelling and imperfections in our test rig, the TE correlation is remarkable. The results are so close that we can use them to inform our design process.”
TE results: simulation vs test rig (1st and 2nd order plots)
Finding the right level of model complexity The second example is a parallel gear stage design. ZF started off by building a very simple Romax model, where simulation results showed a centralised contact pattern on the gears. However, on the test rig, the results were different, with the prototypes showing uneven loading – higher on the left-hand side of the gear. It was unclear at the time whether this was caused by incorrect misalignment, deviations between simulation and measurement, or insufficient time on the test rig, resulting in the paint not indicating the wear correctly.
Although the very simple Romax model (left) showed a central contact pattern (top right), the test rig showed more loading on the left side of the gear than the right (bottom right)
Some additional root strain measurements confirmed the uneven loading, so ZF returned to the Romax model and added more complexity: an FE housing, connections from the outer bearing rings to the FE housing, and set the correct bearing clearances used during testing. This refined simulation model then showed the same uneven loading pattern. Once satisfied with the correlation, ZF could then adjust the simulation model to test out potential design improvements to centralise the contact pattern.
The more complex Romax model with FE housing (left), contact pattern after refinement matching the test rig results (top right), contact pattern after further optimisation (bottom right)
De Bie explains: “Our aim is to have the simplest model to achieve correlation. In this example, we defined the topology based on a very simple model with no housing. However, this did not match what we were seeing on our test rig. So we refined the model until we saw correlation. Once that was achieved, we could use this model to make changes to the micro geometry to centralise the load pattern in simulation, with confidence we would see the same results on the test rig. With this more detailed simulation model, we were also able to obtain more accurate TE results, and subsequently we reduced the risk of noise issues in this design.”
The original simple simulation model (blue) showed decreasing TE above 50-60% torque but the test rig actually showed an increase.After refinement, the simulation model (orange) matched this observation, and some further optimisation of the more complex model improved the TE (grey). Left – first order harmonic, right – second order harmonic
Achieving a simulation-led design process Although ZF Wind have been using Romax software for many years, it has taken time for the capability to be widely accepted as a core part of the drivetrain development process, as De Bie explains, “Initially, we had some work to do to persuade our technical teams about the capabilities. Thanks to the support from the Romax team, we achieved a better understanding of the right modelling approach. We have improved the way in which we use Romax software and the processes which we have in place. We now see Romax as a state-of-the-art tool for advanced gear mesh analysis.”
Stephen Smith, Head of Business Development for System Dynamics at Hexagon, comments on the relationship with ZF Wind: “There was always a common goal between ZF and Romax. Together, we have worked hard to create the right environment for ZF to meet wind turbine challenges, subsequently furthering our joint agenda in sustainability.” De Bie concludes: “Romax Enduro is helping us to tackle the current challenges faced by the wind market. We are able to create a virtual representation of the gear system and the test environment. This means, firstly, that we can fine tune our micro geometry to achieve an optimized load distribution on the gear flank and in the gear root over a wide torque range, and, secondly, that we can detect noise risks early in the design process and identify design measures to mitigate those risks.”
As renewable energy solutions replace traditional power systems, wind turbine installations have expanded worldwide. The falling cost of turbine equipment coupled with design advancements is driving many organizations to utilize renewable energy. A recent report by the Global Wind Energy Council forecasts 235 gigawatts of new offshore wind capacity will be installed over the next decade.
The Challenges of Inspecting Turbine Blades
While wind turbines are a cost-effective and sustainable energy solution, monitoring and diagnosing blade damage is often a challenge. Harsh environmental conditions can accelerate blade wear and tear, which is often difficult to detect. Some wind farms may inspect blades every year, while others inspect only 33% or 25% of their fleet annually, leaving large intervals gaps for defects to grow. By then, the damaged blades may need extensive repairs that involve costly materials and the possibility of bringing the blade to the ground, which translates to extended downtimes.
Offshore turbines are particularly susceptible to inspection and repair delays. This is due to their positioning in areas that are not easily accessible. Such areas also experience unpredictable weather conditions which further delay inspections, repairs, and maintenance.
Detecting Defects Through Acoustic Emission
Since many small-scale defects are invisible to the naked eye, turbine blades require an efficient, real-time monitoring system to detect issues before they turn into costly malfunctions. One innovative method to detect damage uses acoustic emission (AE) by tracking the blades’ acoustic signals during operation.
AE technology uses a combination of sensors and a central monitoring system to detect blade damage. These sensors listen for the energy released by the blades in the form of acoustic sound waves and transmit this data back to the monitoring portal. The sensors capture blade condition data in formats such as hit-based, average signal level (ASL), and waveform streaming (WFS).
Depending on the type of signal received, the presence and type of blade damage can be determined. ASL signals, for example, can report impact damage to the blade. Deteriorating conditions are detected by comparing the acoustic signals over time to identify the defect.
How Sensoria™ Technology Detects Blade Damage
The Sensoria wind turbine blade monitoring system utilizes AE technology to measure defect growth over time. In the installation of the system, an acoustic data collection system is installed in the hub, while a sensor is installed inside each turbine blade.
This data received to the acoustic data collection system from the blade sensors is transmitted to the Sensoria Insights web-based portal which is accessible from any location through desktop and mobile devices. The portal is used for real-time notifications for impacts and defects, to track the presence and evolution of damage, analyze trends across sites and specific blades and track AE data to determine if the defects are active or stable. This assists in prioritizing which blades need more immediate attention, and which can be scheduled for service at a later time.
Operators use the information to track defects and prioritize repair without impacting operations. The Sensoria Insights portal enhances data visibility, allowing operators to efficiently identify assets with recent events or active defects. Upon identification of a new or active defect, Sensoria Dispatch enables a rapid, hands-on inspection or repair to the affected blade.
Blade Issues Detectable Through Monitoring
The MISTRAS Sensoria blade monitoring system functions 24/7/365 to remotely detect defects on blade components. The system detects the following top issues:
- Cracking: Cracks can occur over long periods of time or in extreme conditions. If left undetected, they may lead to catastrophic blade failure.
- Lightning strikes: Wind turbines are easy targets for lightning strikes. With Sensoria monitoring, detection of a lightning strike is captured by a large amplitude and energy signal and displayed on the Sensoria web application for quick identification.
- Blade skin ruptures and perforations: Lightning strikes, fatigue defects, and severe leading edge erosion are the primary causes ruptures or perforations. Acoustic monitoring can identify these issues allowing them to be addressed before they increase in size and adversely affect performance.
- High energy impacts: When natural elements or foreign objects collide with rotor blades, Sensoria can detect these occurences. The location and severity of damage can be determined and help lead to appropriate decision-making.
- Delamination: Wind turbine blades can experience delamination due to numerous causes. Delaminations can be identified early and before any visual indication through acoustic monitoring, hands on tap testing or ultrasonic inspection. If identified early delamination’s can be quickly and efficiently repaired or monitored for growth.
- Bond line failure: Deterioration of the bond lines may occur overtime between the blade’s structural elements. Sensoria can identify active disbanding allowing for targeted inspection before defect growth.
- Other serial manufacturing defects: A leading cause of blade damage is undetected manufacturing defects. If left unattended, this damage worsens during the stresses of turbine operation. Sensoria is able to flag these defects early so that they can be addressed during the manufacturer’s warranty period.
Maximizing Value & Efficiency with 24/7 Blade Condition Monitoring
Sensoria wind turbine blade technology helps wind turbine owners and operators improve efficiency in the following ways:
Site managers and technicians are able to make more informed maintenance decisions with real-time data obtained from the Sensoria Insights portal. Early identification of damage detection assists with maintenance and repair scheduling before problems worsen.
Tracking historical blade conditions and defects through the Sensoria portal gives engineers greater insights into the overall fleet operation.
Reduces transportation and manpower costs due to fewer trips to remote, harder-to-access turbine locations.
Key Takeaways
Condition monitoring of wind turbine blades is a necessity for their continuous operation. However, periodic physical inspections alone are not enough to prevent catastrophic blade damage. MISTRAS Group’s Sensoria provides an innovative solution to this problem through continuous monitoring for greater insights into blade conditions. By detecting changes in the blades’ acoustic signatures, the solution enables operators to locate and correct issues before they worsen, preventing prolonged, costly downtime.
Mağdenli Transport
With an experience longing to a past of a half century, Mağdenli offers transportation, customs clearance and consultancy services on a global scale and offers complete solutions in almost every sphere of international transportation. The wide range of services of Mağdenli, which has registered its quality with a high number of certificates it has received and many awards it has won; In addition to road, airway, railway, marine, combined, project, transit, fair transports and heavy transport; It also includes agency, consultancy, customs clearance, handling, storage and insurance services.
Mağdenli equipments consist of:
- Total 62 Axles Line Hydraulic Axle Platform Trailers
- Goldhofer Pst/Sl-E Type Spmt Trailers
- 200 Tons And 300 Tons Capacity Bolster Systems Installed On Hydraulic Axle Platform Trailers
- Various Drop-Deck Systems For Hydraulic Trailers
- Axles Lines
- Side By Side Hydraulic Platform Trailer
- 650 Mt Capacity Blade Lifter On 12-Axle Spmt
- Extendible Lowbed/Flatbed/Tarpaulin Trailers
- 100 Ton Capacity Extendible Vessel Deck Hydraulic Platform Combination Trailers
- 650 Ton Crawler
- Demag/Grove/Truck Mounted Mobile Cranes
TORKCHECK Service and Consulting
TorkCheck which is a sister company of Mağdenli is established to be technical and commercial solution partner to the customers with the principles such as reliability & honesty, experience and knowledge.
The Company, possessing experienced and qualified teams, operates with the principle that all services are performed according to HSE, quality & environment management rules, to be on the site and complete the work as planned.
Services
- Logistics & Crane Service
- Installation
- Major Operation
- Maintenance & Service
- Composite Services
- Check and Report
Installation
- Mechanical Assembly
- Electrical Assembly
- Finishing Works
TorkCheck always performs each work step in accordance with installation, occupational Health Safety and Environment (HSE) and Quality Management Procedures.
The projects are started on planned date, resume as per schedule and complete before the deadline latest on time.
The challenges which are caused by external factors are resolved in our technical knowledge and experience with the shortest time.
Maintenance & Service
- Periodic Maintenance
- Service Support
- Retrofit
- Rope Access
Our qualified teams minimize the operation costs during maintenance services while carrying out all necessary work steps in compliance with occupational health and safety rules and maintenance instructions.
The range of our operations also cover service support & retrofit services to our customers.
Major Operation
- Blade Bearing Exchange
- Generator Exchange
- Gearbox Exchange
Necessary crane & transportation services are rendered under our service in line with customer demandsThe main turbine components; such as blade bearing, gearbox, generator, pitch motor, transformer etc. are replaced by our experienced teams with full occupational health and safety and high work quality in the shortest time.
All operations are performed with our own tools except for specific ones.
CompositeService
- Blade Check & Repair
- Blade Painting
- Composite Material Repair
- Technical Reporting
The cosmetic or structural repair of the blade or another composite component is repaired & painted by our competent professional team.
Experienced technicians accomplish blade caps’ painting and fix all damages in quick and reliable manner caused by a thunderbolt or during installation & transportation.
We also provide a technical report and inspection. Perform option of manlift or rope access subject to requirement of repair.
Control & Reporting
Our trained technicians check all fastener & bolts by suitable torque equipment, generator alignment, view cable connections by a thermal camera.
The locations which require rope access are observed and controlled by our technicians who possess an IRATA certificate.
High precision electronic steering using spmt
Different make and type blades can be fitted by root internface adapter plate
Computer controlled with accelerometers, inclinators, wind sensors, pressure sensors and gps
Maximum lifting angle more than 80 degrees
Highest stability & maximum safety
6500 lnm blade torque / 650 Mton capacity
Turbine Blades
Gastops reports strong demand for their latest MetalSCAN condition monitoring sensor series for wind turbines
With the MetalSCAN MS3500 series, Gastops sets the standard for oil debris monitoring technology for the wind energy industry.
Gastops, a world leader in critical component condition intelligence, today announced the first volume shipments of the MetalSCAN MS3500 online condition monitoring sensors to a major wind turbine manufacturer for their next generation platform, the fourth manufacturer to adopt MetalSCAN technology as standard equipment.
MS3500 series provides the wind energy industry with online access to real-time condition monitoring data which enables the earliest reliable detection of component damage available on the market today.
“MetalSCAN MS3500 replaces the MS3000 series to further enhance the value proposition for the world’s leading wind turbine manufacturers by helping wind energy operators reduce costs and risk. With the MS3500 series, we have introduced key new functionality and connectivity capabilities to support Industrial Internet of Things (IIOT) implementations at a lower price point, all while maintaining the performance and reliability for which Gastops is recognized.” said Cedric Ouellet, Director of Energy & Industrial at Gastops.
The MetalSCAN MS3500 series delivers real-time detection of 100% of ferrous and non-ferrous metal particles generated during component damage. The sensors generate continuous component condition data to provide advance warning of abnormal component wear or debris accumulation exceeding defined limits. This intelligence gives wind energy operators the power to plan maintenance in advance, predict the remaining useful life of critical equipment, and avoid secondary damage that leads to costly component replacements.
“Our MetalSCAN technology was developed to meet the demanding standards of the aviation and defence markets. As with our previous generation of sensors, the MS3500 series packages that advanced technology into a market leading solution that is now more valuable than ever to both wind turbine manufacturers and operators,” said Shaun Horning, President and CEO of Gastops. “We are very excited to be bringing our latest innovations to the renewable energy industry.”
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