| Can Manatee be used in 3DEXPERIENCE platform? | Manatee 2025x is currently on premise. Long term roadmap includes the availability of Manatee in 3DEXPERIENCE platform to leverage MODSIM capabilities |
| What is e-NVH? | e-NVH means electrical or electromagnetic Noise, Vibration, Harshness, so NVH problems cause by electromagnetic forces. E-NVH includes noise of passive components (inductor, transformers, capacitors…) and rotating machines (electric motors, generators…). SIMULIA Manatee only deals with noise and vibration due to rotating electric machines. Other SIMULIA software (CST x Abaqus x Wave6) can be used to analyze and reduce audible magnetic noise of passive components. |
| What is the difference between Manatee and CST x Abaqus x Simpack x Wave6 workflows? | Manatee is an all-in-one interface that includes e-NVH troubleshooting and mitigation techniques, as well as parameter sweep & optimization. Its specialized algorithm based on linearity of structural dynamics and weak electromagnetic to electric circuit allow to perform fast & accurate calculations in concept and preliminary design stages. CST x Abaqus x Simpack x Wave6 involve four different interfaces to perform e-NVH calculations. It can be used in detailed design phase to perform high fidelity calculations including non-inearities and strong coupling effects. |
| Can Manatee run on my laptop or should I use a remote high performance computer? | Manatee can be run on a standard laptop. Recommended RAM is 16 Go and 10 Go of disk space. Having several cores allows to speed up calculations using the parallelization option of Manatee (by default up to 20 cores). |
| What is the typical runtime of Manatee? | A variable speed e-NVH simulation under sinusoidal supply over 200 speeds should take around 2min, including nonlinear magnetostatic calculations. This calculation is independently from the complexity of the mechanical model (stator Beam Element Model or 3D FEA mechanical model of the full electric drive train) once the modal basis is imported in Manatee format. |
| Can I run several simulations in parallel with Manatee? | Manatee uses the available local cores of a computer to parallelize and speed up computations (up to 20 cores in Manatee 2025x standard license). However, this does not allow the user to run several variable speed e-NVH simulations at same time inside the GUI. When an e-NVH job is running, the user can set-up a new simulation or post process the results of another simulation. "Batch mode" option allows in scripting mode to run several simulations in parallel (up to 20 jobs in Manatee 2025x standard license). |
| Does Manatee require an internet connection? | Even if Manatee 2025x is on premise, its licensing system is a web-based service (Cryptlex) which requires an internet connection (includes a grace period). Only license usage is shared with Cryptlex, there is no transfer of electrical machine data or simulation data. |
| Does Manatee work under Linux? | Manatee 2025x works under Windows only. |
| What electrical machines can be simulated with Manatee? | Manatee 2025x can simulate the following radial flux machines: SPMSM (internal or external rotor), IPMSM, EESM and SCIM. |
| How can I import an electrical machine inside Manatee? | Manatee 2025x does not have import features for electrical machines, which means they must be redefined in Manatee GUI. This allows to define a fully parametric model, making it easier to explore alternative designs with parameter sweeps or optimization. It is planned to include an import feature from CST and Opera. For other electric machine software, you can contact SIMULIA Manatee support team. |
| Can Manatee simulate axial flux machines? | Manatee 2025x does not support AFM. |
| Can Manatee include gear whine noise calculation? | Manatee does not include gear whine analysis due to friction forces in gears. This analysis can be carried combining Simpack with Wave. Manatee can import gear whine to perform an overall analysis of combined magnetic and mechanical noise. |
| Can Manatee excite the rotor with magnetic forces? | Manatee excites both stator and rotor structure with magnetic forces. The contribution of stator and rotor load cases can be separated at the end of the calculation. Important load cases for the rotor are torque ripple (wavenumber 0) and Unbalanced Magnetic Pulle (wavenumber 1). |
| Does Manatee strongly couple electromagnetic & structural dynamics models? | Manatee 2025x does not include strongly coupled physics. It is assumed that all deformations due to magnetic forces are much smaller than the airgap width, so the electromagnetic fields are not changed by stator and rotor vibrations. Other SIMULIA products may be used to study strongly coupled physics, such as the combined effect of UMP and centrifugal forces on an eccentric shaft. |
| How are materials handled in Manatee? | Manatee comes with a multiphysic material library which is used for magnetics & structural dynamics models. B(H) curves and magnet properties are important for magnetic calculations. Young Modulus is used in analytical and semi-analytical stator vibration models. |
| Can Manatee account for Unbalanced Magnetic Pull? | Manatee can include the effect of UMP on noise and vibrations. UMP can appear due to eccentricities or magnetically unbalanced machine. |
| Can Manatee import an electrical machine defined in another electromagnetic software? | Manatee 2025x does not allow importing electrical machine geometry and magnetic materials from other software. The user has to redefine his electric machine inside Manatee, but it always to make it in a parametric way to allow parameter sweeps & optimizations. |
| Can Manatee import flux from third party electromagnetic software? | Manatee can import the airgap flux as .csv files from any electromagnetic software. In that case, the user cannot optimize the magnetic circuit design inside Manatee GUI. Alternatively, calling a Manatee in batch mode with flux import feature allows to run electromagnetic and e-NVH optimization based on a third party electromagnetic solver. |
| Can Manatee account for Pulse Width Modulation? | Manatee 2025x does not include voltage driven simulation with PWM harmonics, it is planned for later release. However, it is possible to import non sinusoidal currents at fixed and variable speed. |
| How can I validate the results of Manatee? | It is recommended to compare Sound Power level measurements (done according to acoustic standards) with Manatee sound power level. The modal basis should be also compared with experiments using Experimental Modal Analysis. It is also recommended to fit the default modal damping of Manatee with experiments. |
| Does Manatee include a mechanical FEA solver? | Manatee 2025x comes with three types of mechanical models: a 2D analytic mechanical model based on equivalent cylindrical shell of the stator stack, a 2D semi analytical model as a Beam Element Model of stator stack, and the possibility to import a modal basis coming from a third party 3D FEA mechanical software. Manatee does not include any mechanical FEA solver, but realizes modal expansion calculations using the imported modal basis. This modal basis can include several components such as rotor and stator, shaft, gears and gearbox, housing, bearings etc. |
| Can Manatee import a mechanical model from third party mechanical software? | Manatee 2025x makes it possible to import a modal basis coming from common 3D FEA mechanical software, including Abaqus. Modal analysis must be run in the third party FEA software. |
| Can Manatee perform rotor mechanical stress calculations? | Manatee 2025x does not carry any mechanical stress calculations under centrifugal forces or magnetic forces. This calculation can be done in third party software like Abaqus. Note that most of the NVH mitigation techniques proposed in Manatee do not change the mechanical stress level in rotor laminates (e.g. notching along D axis, changing slot opening or skew angle). |
| Can Manatee perform mechanical fatigue calculations? | Manatee does not perform fatigue calculations. |
| Can I edit my 3D FEA mechanical model from Manatee GUI? | Manatee does not provide an editor for mechanical FEA models. A realistic 3D FEA mechanical model of the electric drive should be prepared in a third party software by mechanical engineers, and linearized to generate a modal basis to be imported inside Manatee. |
| Can Manatee import an experimental modal basis? | This feature is not yet available in Manatee 2025x. Note that to make this possible, the experimental modal bais must contain at least one slice of stator tooth tips nodes (with acceleration data both in radial and cricumferential directions), and the outer enveloppe of the casing should contain enough nodes for good evaluation of vibration power and ERP. |
| Can Manatee account for lamination anisotropy / non linearities? | Manatee relies on the fidelity of the 3D FEA mechanical model set-up by the user in a separate software (e.g. in Abaqus). If orthotropic properties are defined in this mechanical model, then the effect will be correctly included in e-NVH results of Manatee. Manatee software comes with optional service called "e-NVH coaching hours", so if you need some advices about how to build a realistic structural dynamic model of your structure you can ask SIMULIA Manatee for some support, based on their consulting experience. |
| Does Manatee include an acoustic FEA solver? | Manatee 2025x does not embed an acoustic FEA solver. Export of vibration data as .unv file for use in an acoustic FEA solver such as Wave6 will be available in 2025xR1.
Manatee 2025x acoustic models include analytical radiation efficiency models (when combined with analytical or semi analytical vibration models) and Equivalent Radiated Power (when combined with modal basis import from 3D FEA mechanical model). |
| How can I reduce Manatee computing time? | When running a standard e-NVH calculation, most of the computing time comes from the evaluation of electromagnetic loads. Check if the operating points automatically chosen by Manatee can be further reduced by setting them up manually. Reduce the number of timesteps of the electromagnetic model to focus on the first orders responsible for noise & vibrations. Reduce the mesh size of the electromagnetic model without degrading the accuracy of torque calculation. Running a parameter sweep or optimization at a single speed (e.g. at resonance operating point) and not at variable speed might also help.
If computing time comes from the import of the modal basis, check that the mesh of the 3D FEA mechanical model is adapted to NVH. Decimate the number of envelope nodes and closely follow the modal basis import guidelines of Manatee. |
| Can I change the size of the magnetic mesh? | Manatee automatically sets the mesh size of the magnetic solver. It can be changed in the Advanced options when clicking on the Electromagnetic module in the Workflow tab view. A parameter sweep on the mesh fineness factor can also be performed. Magnetic mesh can be visualized using the Check>Magnetics menu in the icon tab or Check Magnetic FEA button in the electrical machine interface. |
| How can I export Manatee results for further analysis in Matlab/Python/Excel? | An export button is available in most of the visualization graphs to export data as a .csv file. Special export functionalities are available using the Export button of the icon banner (e.g. export of vibration velocity field in .unv). Manatee script can also be called in "batch mode". |
| Does Manatee include an optimization algorithm or should I use my own optimization script? | Although Manatee can be called from an optimization script in "batch mode", Manatee GUI includes a parameter sweep and optimization modules. NVH and electromagnetic metrics are automatically set-up in these environments, and additional outputs can be easily defined accessing to electrical, magnetic, structural and acoustic quantities. For instance, the user can optimize H48 vibration level at a particular sensor node and operating point. |
| When do I have to rerun MLUT (magnetic calculations) ? | MLUT calculations should be rerun when the electromagnetic solution is changed, for instance when the geometry of the magnetic circuit is changed affecting airgap flux distribution. If design changes are only performed on the mechanical integration of the stator, MLUT can be reused. This is how mechanical engineers can easily run what if scenarios at a minimal computing cost (for instance changing the number of ribs of the housing and see the impact on e-NVH metrics).
For more information see |
| When do I have to import again a modal basis? | MLUT calculations should be rerun when the electromagnetic solution is changed, for instance when the geometry of the magnetic circuit is changed affecting airgap flux distribution. If design changes are only performed on the mechanical integration of the stator, MLUT can be reused. This is how mechanical engineers can easily run what if scenarios at a minimal computing cost (for instance changing the number of ribs of the housing and see the impact on e-NVH metrics).
For more information see
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| Where are Manatee results stored? | All Manatee results are stored in the workspace folder chosen by the user when starting Manatee. Magnetic Look Up Tables are stored in "...\WorkspaceName\ProjectName\Data\MachineName\LUT" folder. Modal basis are stored in "...\WorkspaceName\ProjectName\Data\MachineName\ModalBases" folder. |
| Can Manatee be used to simulate magnetic noise of transformers or inductors? | Manatee only focuses on the assessment and control of magnetic noise & vibrations produced by rotating electric machines. E-NVH of passive components can be analyzed using CST x Abaqus x Wave6 worflow. |
| What does r=8 mean? | r=8 means that the force wave has 8 maximum and 8 minimum around the circumference of the electrical machine, it corresponds to the spatial frequency of the force wave, also called wavenumber. An AC machine with 4 pole pairs has a main magnetic force with r=8 wavenumber, which simply means that the force is maximum in front of each pole. |
| What does H8 mean? | H8 means 8 times H1, which is the rotor shaft rotating frequency. It corresponds to the mechanical order 8. Force, vibration and noise have the same frequencies in e-NVH. As most of the excitations are proportional to speed, it is convenient to label them by their frequency divided by the mechanical frequency (their "order") rather than their operational frequency in Hz. |
| What is an electrical order? | An electrical order is the frequency divided by the fundamental electrical frequency (frequency of the alternative current in AC machines). An electrical order of 2 means that the force / vibration / noise occurs at twice the electrical frequency. In synchronous machines, an electrical order is given by the mechanical order divided by the number of pole pairs. In a 4 pole pair machine, the electrical order 2 corresponds to the mechanical order 8. |
| What is a mechanical order? | A mechanical order is the frequency divided by the shaft rotation frequency. A mechanical order of 8 means that the force / vibration / noise occurs at eight times the rotation frequency. In synchronous machines, a mechanical order is given by the electrical order times the number of pole pair. In a 4 pole pair machine, the mechanical order 8 corresponds to the electrical order 4. |
| What is the meaning of a negative wavenumber? | Magnetic force waves may not all travel in the same direction as the rotor. The largest force wave with 2p wavenumber does, but some other harmonics induced by stator winding may travel in opposite directions. In Manatee, all frequencies are positive but opposite traveling directions are accounted for with the wavenumber sign. The sign of force wavenumbers does not change their ability to generate resonances. |
| What is the difference between a wavenumber and a mode order? | The wavenumber of an electromagnetic excitation force relates to its distrubution along the circumference of the machine, it is a "spatial frequency". For example, wavenumber 8 means there are 8 minima and 8 maxima along the circunference of the machine. The spatial order of a mode shape corresponds to the circumferential index of the number of lobes when you vizualize the mode shape along the length of the stator machine. For instance, 0 for a breathing mode of the stator, 2 for an ovalization mode of the stator. This mode order can only be defined when using a cylindrical shell as a simplified modal basis of the stator or rotor. |
| What are the faults / non idealities which can be modelled in Manatee? | Manatee can model static and dynamic, parallel or inclined eccentricities, as well as uneven airgap (with a perturbation model of the electromagnetic field). Uneven magnetization and non sinusoidal currents can also be modeled. Unbalanced currents can also be imported to check their impact on e-NVH. |
| How are magnetic forces applied on the structural model? | Manatee 2025x version excites the electric drive modal basis using lumped force at middle of stator tooth tips, in radial and circumferential directions. Rotor structure is also excited applying radial and circumferential forces at rotor surface. |
| When should I apply magnetic forces on the rotor side? | It is always recommended to include the rotor in the mechanical model (as it can shift some stator/housing modes, besides adding rotor modes), and define the rotor surface sets where magnetic forces are applied. Indeed, torque ripple applied to the rotor may generate structure-borne magnetic noise. In case of eccentricity, Unbalanced Magnetic Pull applied to the rotor shaft can also induce significant magnetic vibration and noise. |
| How do I run parameter studies and sensitivity analyses? | Manatee Parameter Sweep interface in the icon banner allows running parameter studies of all input parameters (geometry, control), even on eccentricity level. |
| Can I perform uncertainty quantification with Manatee? | Manatee 2025x does not include the possibility to introduce uncertainties in mechanical or magnetic properties of the electrical machines. It is recommended to use a Monte Carlo simulation approach in batch mode to obtain NVH level distribution. |
| Why don't my simulation results match test results ? | e-NVH test Vs simulation comparison is a long process that must be carried step by step (electromagnetics, structural dynamics, acoustics). A first difficulty is to run accurate NVH measurements in a semi anechoic chamber without being disturbed by the noise coming from load machine. Even under this ideal conditions, gaps may be observed due to different operational B(H) curves, temperatures, modal damping, eccentricities, uneven magnetization and uneven airgap, etc. SIMULIA Manatee e-NVH experts can analyze those gaps during e-NVH coaching hours. |
