Does the wind industry have a blade problem?

Since primary structural elements in wind turbine blades are designed with carbon fibre spar caps we face increasing damage scenarios by lightning impact.

Lightning can also have a big impact on the blade if there is carbon fibre built in primary load carrying structures like spar caps. Sometimes, lightning only leaves pinholes in the shell; sometimes, some lightning damage propagate to full blade failure if left unrepaired. Insurance companies in US report one-quarter to two-thirds of all wind farm-related claims involve lightning.*

* M.Malkin, A.Byrne, D.Griffin, DNVGL.com: Does the wind industry have a blade problem?, in: North American Wind Power

Semi-automatic linear motor driven sensor delivers focused signal

A phased array ultrasonic spar cap scanning device for uptower rope access is a cutting-edge technology that enables the inspection of spar caps (the primary load-carrying members) in wind turbines. This device allows technicians to conduct thorough and efficient inspections while suspended from ropes on the wind turbine tower. By using phased array ultrasonic technology, it can provide high-resolution imaging and accurate data on the condition of the spar caps, ensuring the structural integrity of the turbine.

This significantly enhances the safety and effectiveness of wind turbine maintenance and inspection and repair operations since uptower repair decision is obviously not only technological motivated but also a powerful business model and commercial cash cow.

Our focus is to invest in this non destructive technologies and gather experience for investigating the feasibility and reliability of a potential repair of the damaged areas in order to increase transparency of residual service life of retrofited blades. 

Let‘s go Odenwald

Again lightning stroke has been observed

Let’s go Odenwald! With a good friend on the set.

(im Bild: Uwe Scherbaum, wind-check.de)

Ohhh, I never saw anyone crawling deeper!

Martin Grabert our expert down under

Dr. Martin Grabert, Brisbane, Australia, now supports HMS Experts & Classification Society (HMS Sachverständige Berlin e.V.) down under. As a student of astronautics and aeronautics he was one of the first coworkers in the first Aircraft Design Company of West-Berlin, the innovative enterprise carrying the letters HMS in its corporate name, dedicated to develop a High Performance Powered Glider Airplane. I proudly present his cumulated professional experience in research support and collaboration activities.

Production related weakness - how do you rate it?

HMS Experts in composite production technology Dr. Mertins and Dr. Holstein evaluating alignment of spar caps congruency to web suspension. What if waves and wrinkles weakens carbon girders? Can asymmetric load case trigger buckling? What if bonding lines of substructure between web and shell and of course at leading and trailing edge is of suboptimal adhesive performance? Can we trust flatback smooth curvature of LE UD reinforcement. Are international varying work behavior and cultural work related disciplin have influence on average blade production quality?

Non-OEM Major Blade Repairs

D-Check of two V44 blades

Wind turbine blade damages spread in terms of its severeness from a cosmetic minor to a major structural relevant level. Not often such fatal damages are beyond profitable reconstruction cost estimates. Original Equipment Manufacturer (OEM) usually play that game with joy selling supposed total losses to insurance companies who are regularly unable to cope. 

HMS "the expert's voice" networks intends to escort blade owners in order to perform major overhaul (heavy maintenance visit) such blade patients without OEM support but nevertheless show long-lasting service life. Independance is our credo enabling potential blade service companies in order to provide e.g. high level carbon fiber repair technology and/or LPS reconstruction. Customers position such turns out to be the winner of unproductive stand-off situation at the end of the day.

It is our focus to handle catastrophic damages, make classification of damage level and design repair measures. We make safe that repair concept, workmanship and performance of repair execution is provided within requested ambitious level. Such we approve the repair trough the power of 20 years independent experts experience and keep an eye on conformity and formal approval referring to certification standards.

Julian Fynn Holstein, youngest Blade Expert in our team

It is rare, but never the less it is true

Just one year old - not having seen extreme conditions when it happend. Some claim, it is a joke of April 1st, I doubt it.

It looks more likely someone has pushed the over speed button too long...

Wellcome on board, Harald Schwarze, Varnish Expert first grade!

Harald Schwarze

HMS Sachverständige Berlin has strengthened its polymer wing of experienced old stagers. Harry has made his carreer all the way through from handicraftsman to member of the board of one of the leading Switzerland based paint manufacturers. He has accumulated profund experience in surface treatment in railways industries and gear box internal painting technology. The actual challenge in production supervision for off-shore rotorblades does entice Harry to break in on his hobbys like wave surfing and jazz drumming.

Living blade experience

"Old fox meeting"

Wolfgang, Ove and Stefan (from left) have in sum more than 50 years of rotor blade experience! I am very grateful for such face-to-face encounter and is one of curiosity of life.

Personal Safety Training (Epoxy and Isocyanates)

Esbjerg, Dk, March 14 and 15, 2013
Most of the guys joining the classroom at AMU-Vest are pretty much familiar with the subject. In order to fulfill the regulations on the education program laid down by Danish law they all surrendered and so they were patient and hold out 2 full days. The "UDDANNELSESBEVIS CERTIFIKAT" was given for remuneration.
W.H.

Siemens blade production accessible via Internet

Siemens Wind Turbines are presented in a high level show case here

It was my pleasure

Twentyeight years after this photo was taken, when the first wind turbine made by Ecotècnia was erected, where you can see (from left to right upright)

Josep Congost, Quim Corominas, Pep Prats, Pere Escorsa, Antoni Martínez, Ermen Llovet,

(and on their knees) Josep Puig, Miquel Cabré, Pere Viladomiu i Xavier Traver

Pep Prats and Miquel Cabré invited me to talk about blade strategy together with Richard A. Schmidt, Patricia Canalis, Alexis de Beaumont and Luca Feigl at Alstom Wind in Barcelona, Spain.
This is very honorfull for me, thank you.

Reliability and Failure Analysis of Wind Power Plants

The international conference "Failure and Damage Analysis" is addressed to manufacturer of wind turbines, suppliers, service provider of operation and maintenance, energy provider, wind farm operator, consulting engineers, technical experts, financial institutions and insurances from all over the world.

Two days in March '13, on 20th and 21st, read more about the program here

Next Generation Unmanned Airborne Vehicles

Cassidian is the defence and security division of the EADS group and a major provider of global security solutions, lead system integration and aerial, land, naval and joint systems. Next generation of airborne military UAV or drones made me fall into evil mood. Visiting the ILA Berlin Air Show 2012 I had first time a feeling like being an engineer in astronautics and aeronautics is an embarrassment.

Never the less, civil use is measurable and we offer our expertise for damage analysis and root cause accessment for claim regulation purposes.

After Sales Service Conference Frankfurt am Main

December 4th and 5th 2012 the 3rd German After Sales Service Conference supported amongst others by Bombardier Transportation, Lufthansa Technik, Bosch and MAN is held to learn from experience of others. Dr. Holstein's contribution is to give an insight in wind branch business processes and lessons learned with respect to off-shore restrictions.

Larger Rotors for low wind sites

Rune Schytt-Nielsen and Flemming Sörensen, Cofounders of SSP

"There is a strong trend towards larger rotors development in order to increase energy production and therefore decrease cost of energy production", Steen Broust Nielsen said when introducing today's challenges in blade design at the SSP site event on EWEA 2012 in Copenhagen. In the same time blade industrie will face an enormous price pressure due to very competetive environment in Asia Pacific.
Reliability concerns with longer blades will put an emphasis on suppliers and after sales service providers with clean records.
We at HMS feel very closed up to the SSP philosophy and have a similar approach to support the provision of blade quality through communication of approved service procedures, staff qualification and independant supervising services.
Feel free to get in touch with HMS Expert's Office, Berlin, mail@rotorcare.eu

Damage class four incident (see also rotor blade damage classes)

Rotor blade maintenance and repair standards are to be correlated to structual blade condition and for repair decisions on basis of damage classes. This posting shows without any doubt a damage class four finding (total loss).

In this case there is hypothesis for fatal blade failure mode by carbon UD-girder  fiber damage due to transverse force stress induced by glass fiber helix winding technique in order to fix the UD-stack in semi-automated beam production process. This issue is discussed in preparation of next Technical Advisory Board Meeting of the AK R (a committee of the German Wind Association, see also www.akrotor.blogspot.com)

Less severe damages like cracks or delaminations have virtually two dimensions. The first dimension visible at a first glance is what we call inspection findings. The second and comprehensive dimension of a damage can be assessed after removing layer by layer of affected material. It is the difference about damage amount and it's range.

Interactive Knowledge Base on NDE of composites

In our every day analysis of failure modes and naming the root causes we recommend to standardize also well defined descriptions and in that sense definitions. Using the right classification for damage classes is one thing we often mention but also choosing the proper expression or definition for irregularities or findings is the other. We recommend the interactive knowledge base at netcomposites website. Http://www.netcomposites.com/ikb/
You will find 19 different failure modes of FRP material like "delamination" or "debonding" or "crack" and I find it very helpful.

Rotor Blade Quality Surveillance requested

Blade quality surveillance (BQS) is one of strongly requested support issues. BQS concept of an Offshore wind farm comprises a complete third party assessment of each key procedure to obtain Type and Project Certificate. It covers design assessment (second phase), blade testing and surveillance of important steps in project (IPE). In order to obtain and retain blade airworthiness periodic monitoring of blade production, witnessing of quality assurance inspections, testing and supervision of whole life cycle operation is mandatory as well as supervision of maintenance and repair acceptance procedures.

HMS Technical Advisers strengthened

We proudly present MATTHIAS VYSHNEVSKYY joining the team. Welcome on board! Matthias has years of experience in flight physics as well as design approval and he is reinforcing the AVIATION wing of the HMS consultancy portfolio.

Lightning strike event scale

We talk about MINOR COSMETIC findings due to LS when only receptors and blade surface in some way swept over by lightning current. In those cases even receptors do not have to be substituted.
A bit more impact is performing the category WEAR OF COMPONENT, where receptors, connections and sparc gap are affected.
If you might find DAMAGE TO COMPONENTS, you have to admit that not only wear of structural integrity had happend, but also overload in critical sectors. You can have reasonable suspicion that lightning protection system is somehow a wrong design.
Incident with BREAK DOWN OF SYSTEM: in this category the component, i.e. blade is desintegrated and has to be replaced or repaired comprehensively.
And if there had been DAMAGE TO OTHER SYSTEMS you might talk about an accident with wider consequences.
(Event scale stated by Thomas H. Krogh, Electricon, Herning, DK)

It is not all about blades

when Blade Experts talk ...
I learned a lot about fly-fishing: Fly fishing is an angling method in which an artificial 'fly' is used to catch fish, Torben Schmidt says. He is one of this great sport enthusiasts

Hijacking a single engined aircraft

I could not believe it's true when I first heard of this incredible story my client presented the other day. But after his explanations on the phone I felt he is apparently in big trouble to verify an insured loss and I promised to try my best to help. Here is the original report of an enthusiast and member of PlanePictures.net André Garcez:

(LPCS Cascais, Portugal) 12-February-2010: Private Pacific Aerospace PAC-750XL André Garcez D-FGOJ c/n 139. ex ZK-JDQ. Straight from a Hollywood movie. A ex-military hijacked the aircraft, after pretending to be a photographer shooting parachute jumps from inside the airplane. The aircraft took off from LPEV (Évora) to LPCS (Tires) with 2 parachuters, and right after, the hijacker diverted the aircraft using a pistol. When the aircraft was landing at Tires, the pilot managed to take the weapon from the terrorist, but he went for the controls and tried to crash the airplane. The parachuters jumped at very low altitude and the aircraft landed with the engine shut down, with a strugle between the pilot and the hijacker, skidded into a ditch breaking the left wing and left again to the grass breaking the landing gear. The pilot jumped from the aircraft as soon as it hit the ground and the hijacker committed suicide (you can see him underneath the left wing). It also seems that the hijacker's car exploded in Évora. Handheld, raining a lot, and almost dark.

Incredible story, isn't it? What brave reaction this pilot had shown! I would have been scared to death...

Ironic Australian decision

Australian government decided to cancel photovoltaic funding in order to take care about flooding wrap-ups.
Australian thinking not always comprehensible for me.

My comment on Vestas blade incident announcement

Blade incident on V112-3.0 MW prototype in Lem, Denmark
(Ref: Vestas announcement No. 35/2010)

Randers, 10 September 2010: On Wednesday 8 September 2010, a blade piece detached from Vestas’ V112-3.0 MW prototype wind turbine located in Lem, Denmark.

Rotor blade damage classes

1. Preliminary Note

The aim of this posting is to describe classes of findings within damage assessment and its requirements and responsibilities of servicing.

Blade production evaluation through damage assessment experience

Request for partnership with Benchmarking Center (ICB) at Fraunhofer IPK Berlin was wrapped up in order to define strategies for best practices on a management level of this sector. Dr. Holstein explained the core structural blade characteristics of turbine market leaders, common production technologies and its history and name the most frequently identified production related blade failures. His contribution was peppered with numerous updated inspection findings. Main difficulty in walking through the 5 step benchmarking model is the acquisition of the right industrial partners to join an open minded process to learn. I hear you say: This is impossible in wind business! But what the hell, I like this basic approach option.

Non destructive testing of blades before installation

Again questions arise if there is a way to test blades before installation or even after mounting with ultrasonics and/or infrared technology in order to quantify quality level or invisible or masked failures.

NDT techniques like the mentioned (US and IR) today (and I think for a long time in future) are not made to be used as a method for inspection of blades before installation in farms under construction. Both techniques have to be selected and adapted for the case of inspection one intends to do. IR has good features if you search for defects close to the surface. US have better potential if you want to look into the deep layers of structure. But non of these techniques can be used from root section to tip without dramatic change of parameters and system devices and measuring methods like frequencies, coupling heads, calibration and software setup. In other words: if you already know what kind of local fixed defect you are searching for and you already have tested and evaluated all these parameters for this case of testing, you have a slightly chance to be successful to find what you search for.

NDT like US and IR is not an all-purpose inspection feature and are to be chosen for very special assessment of blade defects. A day to day holistic blade quality inspection (inside and outside) like we do in many cases before installation is based on knowledge of the specific production process of the series production, the experience of noticed problems with this type of blade and the intuition of an old fox in the field of polymer chemistry, structural principles of blade design, aerodynamics, mass-dynamics of lightweight structures and last but not least independent standing of experts reference.

If you believe NDT blade testing is ready and in place for an universal monitoring of blade quality you may have been trapped by pseudo-scientific stories about fantastic new imaging techniques which is fiction for sure.

You ask for more information about the book project: tell the story of a case

First of all I would like to thank you all for your openness to contribute in one or the other way. I would very much appreciate if you could manage to describe a case where your technique or the concept you promoted was successful. This might be, for example, NDT in detecting rotor blade defects. There is some fascinating experience I know of, where ultrasound specialists have scanned sandwich sections with balsa core material where glass fibre layers were partially cut in some inexpressible stupid production process steps. If you don’t mind and if you are able to tell this story without embarrassing the involved parties, this way of illumination of the manuscript has my preference. That long winding canticle your competitors offer talking of putative ingenious equipment is boring to me. My intention is to act on fact boiling down the stories of this book.

I have some other "stories", or let us say "cases" in mind:
-> the peril of what we call greased lightning or
-> the putative efficiency of the 24 hours production cycle or
-> total blade quality through cascading qualified subsystem elements like embedded inserts, pultruded or prelaminated and consolidated structural sections and others.

What about your "story"? No wrinkles, collapsed flanges, tumbling webs ...
How do you feel about active load controlled single pitched blades?
What is the first thing you blade-brained guys have in mind if you go for 10 Megawatt machines?

Anyway - deadline of this call for contribution is coming up soon and I will get back to you offering a conference call for authors of the short list.

Take care - we do.

airborne inspections available

Encounter of my debut flight apparatus and its derelict

My personal flight career started on the rear seat of a C 172 with tail index D ELSE. This aircraft was owned by the Technical University of Berlin, astronautics and aeronautics branch, institute guidance and control and me at that time in the main study period to graduate for my engineer degree.
Its last mission was to deliver sky divers at my club at EDVH, the place out of which I operate my Airborne Blade Inspections.
Ashes to ashes and dust to dust.

I had a dream last night

And it does not seem that everything is all right. Long and winding roads were leading to this land of change where the wind was driving huge blades onshore and even more gigantic ones way out on sea providing turbines at its best. One can believe it is well done for our children and we always knew we should do it in the right way and this means to invest as much as we can to get off this oil and gas consuming way of life. Our personal capacity to invest is restricted. We invested our heart and brain and the wisdom grown was swallowed by affiliated groups of global players. So my dream ended with an apparent suicidal drop off the nacelle of a wind turbine. What I found this morning is that b.a.s.e. jumping is more naive and narcissistic than suicidal. Watch them jump, click here

What is essential to improve blade lifetime?

What is your opinion? How can we have best influence to improve blade lifetime?

:1: improve design?

:2: improve production technologies/quality management?

:3: improve maintenance and overhaul?

:4: improve terms of storage and transportation?

:5: improve inspection and blade accessment/on-site NDT method?

:6: improve meteorological prognosis?

:7: improve or develop realtime load measuring/managing and condition monitoring systems?

How do you feel we can improve - what is your experience? Do not hesitate to comment.

Frequently asked question about automatic blade inspections

These days I receive numerous mails and phone calls pointing out there is a new automatic blade inspection device available.

“Do you know this robotic system?” they ask. Yes, but …

From time to time you may find breaking news about putative brilliant inventions to solve the necessary blade inspections without the needs of a human inspector. Fantastic ideas are presented and spread out full-bodied across mainstream media. I don’t mind if this information is precise and do not keep quiet about the fact that this is based on academic style pipe dreams, chimeras to win project sponoring and not worth to deal with it. I even don’t mind the fact originators have to suffer in their upcoming insomnia which may develop to a full-grown nightmare when the truth was made public. It is for sure that top-ranking scientific institutes may suffer the loss of their reputation playing around like this.

Sorry, I don’t care.