TWD increases confidence and efficiency of transport by friction measurements

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TKI Wind op Zee

Pioneering SME: TWD

It can be dangerous when monopiles start moving during sea transport. To prevent this from happening, contractors have to work with strict safety requirements in their design of sea fastening structures. However, what if a company would know exactly how much the friction between the monopile and the sea fastening is in different weather conditions? Then, a lot of transport costs can be saved, says Jelmer Jacobs of engineering consulting company TWD. For TWD innovation is core business.

"We design auxiliary structures and equipment for offshore transport and installation, especially in the offshore wind industry. However, it is not enough to help our customers by just being an engineering consulting company. That is why we have expanded our R&D-team since last year to four engineers who are constantly looking for trends and new ideas in the market to solve common problems. We want to make our customers work more efficiently in this dynamic offshore wind market. An example is the Motion Compensated Pile Gripper, a piling frame to install monopiles from a floating ship. Another example is the mini-jacket, a three-legged foundation as a lightweight alternative to current foundations. We have demonstrated the technical and commercial feasibility of these innovations. "

For what problem have you found a solution now?

"To prevent monopiles from moving during sea transport, some companies choose to physically secure the piles. For many years, TWD has been using a steel saddle with a layer of rubber. For rubber interfaces, a friction coefficient of 0.3 is prescribed. However, a single fixed number does not represent the reality. It does not say anything about the influence of wet, salty or ice cold environmental conditions. In addition, the friction of new materials in the offshore wind market, like  coated steel or polyurethane material combinations  are not (yet) included in the regulations. Companies only design to comply with the statutory codes. This may mean that they use too low or even too high friction coefficients."

What is your solution?

"Together with TU Delft, we have developed a measuring system, which accurately measures the friction coefficients for different material combinations and various conditions. The test setup includes a tensile testing machine and a clamping mechanism for wood, rubber or steel samples. With this set up it’s possible to simulate the actual transport conditions"


What's so pioneering about your application?

"There are several companies that measure the friction coefficient of a material, such as material suppliers themselves. However, we can quickly and efficiently determine the friction coefficient for combinations of different materials. In addition, it is unique that we, as an engineering firm, perform friction measurements for the specific circumstances in which the materials are used. We are specialized in delivering customized work. The combination of engineering and practical measurements ensures efficient and correct designs. "

What are the benefits?

"Measuring gives  the contractor certainty about the friction and avoids using too much material. The measurements enable the company to optimize sea fastening design and to apply innovative materials, or not. If the material has a high friction coefficient of 0.5, you need less steel to achieve sufficient clamping force. And vice versa."


Where are you now?

"The results of the measurements are consistent. A surveyor will review the new test setup and will assess the measurements, so we can provide customers with certified test results. This gives them a lot of certainty in an early stage, especially because friction is always a topic of discussion. "

What are the challenges?

"The challenge is to convince our customers of the added value of the measurements. Regarding the sea fastening methods, they are used to designs according to the code: so why make changes when they have a method that is working? Although a small investment in measurements is quickly recovered, that's still a threshold we need to cross.”


What is the added value of InnovationLink?

"Martin Weissmann from Offshore Wind Innovators has a lot of experience with business development in a technical company. We are a young company, so he  was very valuable as a sparring partner. We have also expanded our R&D team recently, which enables us to roll out many new developments. Martin Weissmann helped us to determine our focus and the most appropriate steps to take. A good example is the Funnel method. This method gives us a firm grip on the faster assessment of viability of new ideas and ensures that we involve the market on time."

What are your next steps?

"The friction setup is the first measurement service that we have rolled out. Now, we would like to use other measurement principles to further improve and optimize our designs. In addition, we make full use of the knowledge we have in TWD about measuring systems and micromechanics."


This article has been prepared in cooperation with the Offshore Wind Innovators.

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