Norway: Sesam Brings Together DNV and Fedem Technology

Norway Sesam Brings Together DNV and Fedem Technology

Two forces in the software industry, Fedem Technology and DNV Software, have joined forces to produce a new module for coupled analysis in Sesam Wind. The module for coupled analysis is an integration of FEDEM Windpower and Sesam.

Fedem Technology, which has been developing software for more than 20 years, produces the leading software for fully integrated analyses of mechanical systems and structures in motion.

The soon-to-be-released software module will be the newest addition to DNV Software’s product portfolio in Sesam Wind. It incorporates state-of-the-art algorithms geared toward structural analysis, completing DNV Software’s solutions for wind turbine design, strength and fatigue analysis. Many different users – from substructure designers and turbine manufacturers to wind park operators and verification bodies – will benefit from the new package.

Features ranging from the purely mechanical aspects of a wind turbine to customisable control systems and detailed wind and wave loads make it a versatile tool for complete dynamic modelling and analysis of any wind turbine project.


“It saves costs by optimisation of wind turbine design and work processes,” says Gunnar Paulsen, Fedem Technology’s Operations Manager, about the fully integrated analysis system. The module will reduce uncertainties and improve work efficiency in design and verification of offshore wind turbines. A consistent model can be used throughout the wind turbine and substructure analysis. Engineers no longer have to deal with challenging interfaces and iterative work for tuning the wind turbine model and the substructure model.


The module is built over the FEDEM simulation engine and contains several features that facilitate the modelling and simulation of wind turbines. Fedem Technology has already served several offshore wind farm projects in Norway, the UK and Germany with their engineering capabilities and software solutions.

FEDEM is an abbreviation for Finite Element Dynamics in Elastic Mechanisms, and is a comprehensive simulation engine that has been under development for more than two decades. FEDEM has been extensively used in many industrial applications, ranging from car suspensions to offshore drilling systems and marine operations. Common for the applications are nonlinear dynamics with long time series, for assessment of product life and strength.

Each mechanical component in the module can be represented with a finite element mesh. Components can be connected using any kind of joints, with arbitrary non-linear coupling properties. A key feature is the automatic model reduction that makes it possible to represent any structural element with desired fineness of the mesh, without any additional cost of solving time. Hence complex structures, that need to be represented with shells or solids to obtain adequate models, can be used.

The interaction with wind is based on the BEM (Blade Element Momentum) model, where the aerodynamic properties for the blade segments are given by a set of airfoil coefficients. In addition, the blade elements can be assigned structural properties to the desired level of detail. Large non-linear deformations for the blades are then covered, and also the effect such deformations will have with respect to wind-structure interaction.

The interaction between the structural elements and the sea is based on the Morison approach, which is an industry standard in the offshore sector. This makes the module suitable for monopiles, jackets and other framework substructures, as well as most types of floating structures. Waves can be regular or irregular, applying wave frequency spectrum for the latter. Non-linear waves can also be tested, checking for ringing effects.


Control systems are crucial for wind turbines, and several options for control modelling are available. A versatile graphical control system designer is integrated in the tool and lets you define any kind of control system with input and output coupled to the model. In addition there is a standard Variable pitch-Variable speed controller. It is also possible to have a custom DLL control system on demand.

A common requirement for the testing and verification of offshore wind turbines is long time series with many combinations of wind and wave input, giving a large number of simulation events. The multi-event handler lets the user set up all kinds of parameter combinations that are subsequently executed in batch, running processes in parallel on each CPU core.

The integration with other modules in Sesam Wind makes it possible to import components from GeniE Wind, carry out the simulations and automatically export results that can be subjected for code checking. The user-friendly combination gives a complete tool for modelling, testing and code checking for offshore wind turbines.


Press release, January 29, 2013; Image: dnv