Periodic Reporting for period 1 - ASSO (Adhesive Connection for Secondary Structures in Offshore Wind Installations)
Période du rapport: 2019-09-01 au 2021-08-31
The production of renewable energy represents a relevant topic that day after day affects the life of every citizen more and more. Over the years, scientists and industries have been interested in the study of new renewable energy sources in order to give a concrete answer to the world's energy needs.
Among them the development of floating (offshore) wind turbines on a commercial scale grows considerably each year after that different countries have recognized them as the best solution for the production of sustainable energy. In order to satisfy the required needs of safety, serviceability, durability and affordability, new technologies are required: the actual connections and the secondary structures have to be replaced by a new one based on the bonding technique.
The vast majority of connections will be done using welding and perhaps some other mechanical joining process such as bolting or riveting. However, there are many situations where these joining processes are not the optimal solution also for safety reasons. In addition, avoidance of high welding temperatures leads to safer construction in hazardous environments and besides it will make positive contributions to the preservation and improvement of the quality of the environment by reducing the amount of welding slag created.
Adhesive bonding in the marine environment for offshore applications is still very much in its infancy in spite of some successes. However, much is still needed to establish this joining process as a standard process in offshore considering the design, fabrication and modification of offshore structures. In order to propose reliable solutions it is essential to be able to guarantee long-term properties and sufficient mechanical strength.
In fact, the long-term durability of joints in critical environments has been recognized as one of the factors which have limited more widespread application of adhesives for marine and offshore structures.
Among them the development of floating (offshore) wind turbines on a commercial scale grows considerably each year after that different countries have recognized them as the best solution for the production of sustainable energy. In order to satisfy the required needs of safety, serviceability, durability and affordability, new technologies are required: the actual connections and the secondary structures have to be replaced by a new one based on the bonding technique.
The vast majority of connections will be done using welding and perhaps some other mechanical joining process such as bolting or riveting. However, there are many situations where these joining processes are not the optimal solution also for safety reasons. In addition, avoidance of high welding temperatures leads to safer construction in hazardous environments and besides it will make positive contributions to the preservation and improvement of the quality of the environment by reducing the amount of welding slag created.
Adhesive bonding in the marine environment for offshore applications is still very much in its infancy in spite of some successes. However, much is still needed to establish this joining process as a standard process in offshore considering the design, fabrication and modification of offshore structures. In order to propose reliable solutions it is essential to be able to guarantee long-term properties and sufficient mechanical strength.
In fact, the long-term durability of joints in critical environments has been recognized as one of the factors which have limited more widespread application of adhesives for marine and offshore structures.
The main objective of the ASSO project has been to enhance the knowledge on the performance of adhesive connections in the marine industry through a significant research program comprehensive of both experimental and numerical approaches.
In particular, a wide experimental program has been undertaken at Laboratory of Mechanics and Acoustic of CNRS in Marseille (France) in order to create a large experimental database able to provide the mechanical properties and capacity of adhesive connections subject to different load conditions and aggressive environments.
The experimental tests have been performed on specimens made by different materials and connected each other’s by means of different type of glues available on the market.
Static, cyclic and fatigue regimes have been applied by means of universal testing machine and seawater conditions were created in laboratory.
Furthermore, a methodology for studying the mechanical behaviour of metal adhesive connections and complex structures made of GFRP members joined together by means of adhesive joints has been formulated.
The methodology is based on an imperfect interface approaches and material chosen follow the Kachanov assumption. The mathematical equations are able to analyze the performance of adhesive connections under different load regimes.
In particular, a wide experimental program has been undertaken at Laboratory of Mechanics and Acoustic of CNRS in Marseille (France) in order to create a large experimental database able to provide the mechanical properties and capacity of adhesive connections subject to different load conditions and aggressive environments.
The experimental tests have been performed on specimens made by different materials and connected each other’s by means of different type of glues available on the market.
Static, cyclic and fatigue regimes have been applied by means of universal testing machine and seawater conditions were created in laboratory.
Furthermore, a methodology for studying the mechanical behaviour of metal adhesive connections and complex structures made of GFRP members joined together by means of adhesive joints has been formulated.
The methodology is based on an imperfect interface approaches and material chosen follow the Kachanov assumption. The mathematical equations are able to analyze the performance of adhesive connections under different load regimes.
The results obtained were very positive and exceeded expectations by fully introducing adhesive connections suitable for applications in the marine environment.
The results of the project will significantly impactful for the research community and marine industry providing essential knowledge in the field of adhesive connections that will allow to substitute existing secondary structures or create new ones decreasing time and costs. This could allow a rapid deployment of offshore wind installations for sustainable energy production, an ambitious target set by the EU.
Furthermore, the ASSO project has received a large interest and appreciation by the French industry IDEOL considered as leader in the sector of wind offshore installation. IDEOL found the results of experimental tests of adhesive connections very interesting, promising and innovative and expressing great interest for possible future applications.
The results of the project will significantly impactful for the research community and marine industry providing essential knowledge in the field of adhesive connections that will allow to substitute existing secondary structures or create new ones decreasing time and costs. This could allow a rapid deployment of offshore wind installations for sustainable energy production, an ambitious target set by the EU.
Furthermore, the ASSO project has received a large interest and appreciation by the French industry IDEOL considered as leader in the sector of wind offshore installation. IDEOL found the results of experimental tests of adhesive connections very interesting, promising and innovative and expressing great interest for possible future applications.