Samcef ROTORS versus MSC NASTRAN V**

Samcef ROTORS versus MSC NASTRAN V**Patrick Morelle – 8/8/2012

http:WWW.//ablemax.co.kr5nd floor, Hanho Building, 90-14 SamSung-1 Dong,

KangNam-Gu, Seoul, Korea Republic of TEL: 02) 539-5212FAX: 02) 539-5213

E-mail: [email protected]

LMS Samtech Division Copyright LMS International - 2012

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Comparison S4R - MSC NASTRAN

S4R MSC NASTRAN Dedicated GUI and integrated

solution for rotor dynamics

Improved conical beam element (degenerated shell, better taking into account conical shafts)

2D Fourier models without limitations in the number of harmonics (0, 1 and higher orders). Possibility to use them for composite materials.

2D Fourier Lagrangian and Eulerian approach

No specific GUI. Rotor dynamics capabilities as part of global FE solution

Classical beam element

NO 2D capabilities

NO 2D capabilities


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S4R MSC NASTRAN 1D, 2D, 3D, cyclic symmetry, multi

stage cyclic symmetry, all exhibiting gyroscopic effect, and possibility to combine all of them

Superelement technique for rotating parts AND non rotating parts. The rotating superelement include reduced stiffness, mass, damping, gyroscopic and circulatory forces matrices

General gear element allowing to take into account coupling between axial, bending and torsion modes

Only 1D and 3D, no combinations between different types of models. 3D models are using static condensation method : the nodes are condensed along the axis of rotation (rough “rigid” gyroscopic effect versus our “flexibel” exact one)

Superelement technique ONLY for non rotating parts in inertial frame (except the requested static condensation of 3D model along axis of rotation …)

No gear


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S4R MSC NASTRAN Large library of specialized bearings

(hydrodynamic bearing, rolling element bearing, squeeze-film damper, added mass effect fluid elements), prototype BEARING module for hydrodynamic bearings (normal and thrust)

Bearing element with 6X6 matrices (stiffness, damping (viscous or hysteretical), mass) The coefficients are either constant or variables with rotational speed, frequency or time

Bi-variable (rotational speed and frequency) bearing element with 6X6 matrices (stiffness, damping, mass)

No specific bearings (modelled with generic “spring”/CELAS + constraints/RBE elements), squeeze film damper available

General stiffness/Damping matrix (MATRIX27) CONSTANT (no dependency of the speed of rotation)

Only constant matrices


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S4R MSC NASTRAN Local non linearities are taken into

account in the frequency domain ( non linear harmonic balance method). Available : bushing (clearances), rolling element bearing, squeeze-film damper, friction element

Improved integration schemes in time domain, and on non linear elements available : bushing (clearances), rolling element bearing, squeeze-film damper, friction element, hydrodynamic bearing element

Only classical harmonic analysis

No specific integration scheme and no specific non linear elements


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S4R MSC NASTRAN Specialized and advanced post-

processing included in the GUI

Automatic 3D recombination of 2D and cyclic symmetry models including multi stage cyclic symmetry

Campbell diagram available for problems in inertial AND rotating frame. Very efficient mode tracking process.

No specific GUI, use command language to post-process rotor model

No 2D …

Classical mode tracking process (users complain about it).

Samcef ROTORS versus MSC NASTRAN V**

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