Feature Comparison
Feature  Mechanical  Offshore  Windpower  More 

Nonlinear structural dynamics 


In multibody applications such as wind turbines, dynamic offshore systems, suspension systems, axle systems, car bodies, satellite appendages, industrial manipulators, medical equipment, highspeed mechatronic systems and so on, some of the mechanism components can be flexible and can experience large elastic deflections and coupling effects. To ensure sufficient accuracy, the simulation solver must account for the mutual dependencies between dynamic properties at the system level and structural flexibility at the component level. These requirements can be efficiently satisfied through a nonlinear structural dynamics approach.


Dynamic solver 


The FEDEM Dynamics Solver module performs a nonlinear dynamics simulation. This means a simulation of the motion and deformations of the superelements and the joints, as they respond to load and displacement time histories and Control System output.


Mode solver 


The Mode Shape Recovery module recovers the mode shapes of each part from the Eigenvalue results of the Dynamic Solver. 

Stress recovery solver 


The FEDEM Stress Recovery module recovers the internal DOFs from the deformations of the external DOFs simulated by the Dynamics Solver. The element stresses, strains and beam forces are then calculated. 

FEmodel reducer 


The FEDEM Reducer performs a superelement reduction of the FE model representing the mass and stiffness of a part. A superelement reduction reduces the required DOF to a minimum. The retained DOFs, also called external DOFs, are the results of a dynamic superelement reduction technique called Component Mode Synthesis reduction, also known as CMS reduction. More information on this topics can be found in FEM textbooks. 

Multievent analysis 


In many analysis projects using FEDEM, the task is to investigate the response on a given structural model, or a set of almost identical models, for a large set of load cases, or events. To facilitate such projects, FEDEM has introduced the concept of Simulation events.


Curve plotter 


FEDEM includes a powerful curve plotter that can be used to plot any of the results data in the detailed results database from object positions to forces and moments. The curve plotter includes important tools, such as curve statistics, fourier analysis and differentiation, rainflow and fatigue, and more. 

Nonlinear joints 


FEDEM has a powerful nonlinear joint modelling capabilities, supporting everything from pointtopoint joints (e.g. revolute, ball, rigid and free) to more complex joints like prismatic, cylindric, cam, gear and rackandpinion joints. Springs and dampers can be used, force and torque can be applied, sensors can be used to measure, and flexible/rigid surfaces can be used to attach triads to nodes on FEmeshes. You can also define your own functions and plugins to extend the capabilities. 

Beam cross sections 


Beam cross sections are used to describe the cross section properties of a beam element. 

Material properties 


Materials are used to describe material properties of beam elements (linear isotropic materials only). They are referred to via the Beam cross section objects (described above). 

Control system editor 


Real mechanisms are often connected to or acted upon by control elements such as sensors, controllers, and actuators. A control system is therefore necessary to simulate these effects for FEDEM mechanisms. FEDEM’s blockdiagram presentation of control systems closely resembles that given in most textbooks about basic control theory. The graphical representation consists of a series of connected control blocks, which you can model to simulate your control requirements. 

Generic parts 


Generic parts are useful for fast modeling of simple structure parts where a full mesh will not be necessary. Generic parts are modelled as a "point cloud" of triads that are rigidly joined together. 

Beams, shells and solids import 


Detail finite element model possible for all components.At no cost of calculation speed!


Userdefined functions 


Functions can be used to control the magnitude of loads, the length of springs, prescribed motion in joints, etc.


Time history input data 


A special type of function definitions are the Time history input file object. This object behaves essentially as a function of time, but is optimized to be used for input of time history data from any external files. 

Virtual strain gauges 


FEDEM provides tools to gauge strain anywhere in the model. 

Stress contours 


FEDEM provides complete and animated visualization of stress contours. 

Fatigue contours 


FEDEM provides complete and animated visualization of fatigue contours. 

Curve fatigue 


FEDEM provides tools to easily calculate fatigue on any result curve. 

Time history export 


FEDEM provides support for detailed export of time histories. 

Fatigue summary interface 


Fatigue summary is another useful tool. You can do a fatigue summary analysis on any graph or set of curves in FEDEM. Just select a graph or set of curves, right click them, and choose "Fatigue Summary..". If you have multiple events in your model, then fatigue summary will be calucated for each event. You can adjust the probability values ("Prob"). 

Beam results diagram 


FEDEM provides easy generation of force and moment diagrams along the beam. 

Wavestructure interaction 


FEDEM provides advanced support for wavestructure interaction. 

Irregular sea states 


FEDEM provides support for simulating irregular sea states, such as e.g. JONSWAP, and also supports userdefined wave spectrums. 

Current profile 


FEDEM provides support for a large range of current functions. 

Response amplitude operators 


The goal of a vessel Response Amplitude Operator (RAO) is to express the motion of a point on a rigid vessel floating in the sea as a function of the wave height at the same reference point. The concept of a RAOs is associated with the stationary sinusoidal response (or motion) of a linear system due to a stationary sinusoidal load (wave). 

Internal fluid in beam elements 


FEDEM supports internal fluid calculations on all beam elements. 

Marine growth definition 


Fixed marine structures in shallow waters are often burdened by extra weight due to marine growth over the years of operation. This added mass contribution may have a significant impact of the dynamic behavior of the structure, when subjected to loads due to wave and/or current. 

Soil piles and py curves (SSI) 


FEDEM provides advanced support for soilstructure interaction.


Spaceframe import 


A spaceframe in FEDEM is an assembly of several Beams which are connected to each other in Triads. An arbitrary number of beams may be connected at each Triad. Thus, it becomes a full FE representation of the structure on the system level. A spaceframe is represented by a Subassembly element of the subclass Jacket in the FEDEM model. A Jacket is a model of a bottomfixed offshore structure, which are typically used as foundation for wind turbines and oil exploration platforms. The beam members of a Jacket structure may therefore be assigned properties for hydrodynamic load calculation (added mass and drag coefficients). 

Beamstring pair definition 


The Beamstring Pair Definition tool is used to generate Free Joints between the triads of a beamstring pair. The primary purpose of this approach is to simulate that the inner pipe hits the outer pipe, and then the inner pipe will bounce back. The Contact stiffness function provides the magnitude of the contact spring that is applied on all joints. The Use radial springs check box indicates whether radial springs are to be used. 

Turbine definition 


The Turbine definition dialog box is used to enable easy configuration and creation of wind turbine models. All the fields have predefined default values, so the only thing you need to do in order to generate a valid wind turbine model is to click the "Generate turbine" button.FEDEM Windpower uses the AeroDyn software module of the National Renewable Energy Laboratory (NREL) in the USA (http://wind.nrel.gov), for all calculations related to the aerodynamic loads on the wind turbine blades. These loads are then applied onto the structural model of the wind turbine in the FEDEM solvers, to provide response data that can be further analysed. 

Blade definition 


FEDEM Windpower includes some sample blade designs (e.g., the file "Sample5MW") within the installation. You can just specify one of these sample blades in the Turbine definition dialog box, if the blades of the turbine are not the main focus area for your simulation. However, most projects will require that the blades are defined in detail for that project. This is performed in the Blade Definition dialog box, shown below. 

Airfoil definition 


The purpose of the Airfoil Definitions dialog box is to facilitate the creation of a set of airfoils to use in the turbine blade definition. An airfoil is basically a cross section of the blade where different aerodynamic properties (drag and lift coefficients, etc.) are specified around the blade.


3D turbulent wind 


The FEDEM TurbWind tool is used to generate turbulent wind files for the Air environment dialog box in FEDEM Windpower.


SESAM integration 


FEDEM provides integration features for DNV SESAM. 
For a more detailed study of the FEDEM features and capabilities, please have a look at the application examples.