Visual SDM™ helps you quickly evaluate alternative solutions to resonance problems by adding additional tools to the modal analysis features of a Visual Modal™ package. The Structural Dynamics Modification (SDM) method allows you to examine the effects of a variety of potential structural modifications on the resonances of a structure without actually having to make the physical modifications.
Visual SDMTM
VT-540
VT-540 Visual SDM™ calculates the effects of making physical modifications to a structure on its modes of vibration. With SDM, FEA elements can be added to (or subtracted from) a structure model, and the new modes of the structure are calculated. The SDM commands use industry-standard finite elements. Finite elements are called FEA Objects in MEscope.
Visual SDMTM Key Points:
- Count the number of modes using a Mode Indicator function
- New Modes are quickly calculated that show the effects of multiple modifications
- Estimate a modal residue (a mode shape component) for each mode & each measurement.Industry-standard FEA elements Physical modifications are modeled using industry-standard FEA elements
- Many “What If” cases Fast calculation allows many potential modifications to be explored
Visual SDMTM Features
Modifications Modeled with SDM
- Masses Point Masses that model translational or rotational inertia
- Springs & Dampers Linear translational or rotational springs & dampers that model axial, 3 DOF, or 6 DOF forces
- Rods the model cross sectional properties
- Beams the model cross sectional properties and inertias
- Triangular & Quadrilateral Plates that model translational & rotational properties
- Tetrahedron, Prism, & Brick solid elements
- Tuned Absorber (model a mass-spring-damper to reduce vibration levels)
- Sub-structuring Couple together multiple structures
- Modal Sensitivity Find the best solution among 1000’s of potential modifications
Modal Sensitivity Analysis
- Answers the Question “How much stiffness is needed to shift a mode to a higher frequency?”
- Answers the Question “How much mass can be added without shifting a mode too low in frequency?”
- Answers the Question “How much joint stiffness is needed to match several target EMA frequencies?”
- Solution Ranks 1000’s of modifications based on the difference between modified & target modal frequencies & damping
- Modified & target modes Modified & target mode pairs can be selected for ranking solutions
Finite Element Analysis (FEA) in ME’scope
- Element Library Uses a library of industry-standard FEA elements
- FEA Assistant Populates the 3D model with FEA elements
- Element Library Uses a library of industry-standard FEA elements
- Material & Element Properties User-defined material & element properties saved with each Project
- FEA Modes Normal modes (with no damping) or Complex modes (with damping) are calculated
- Shape Expansion FEA mode shapes can be used to expanded the DOFS of ODS’s and EMA mode shapes
- Import & Export FEA models and FEA modes imported from & exported to NASTRAN, Ansys and other popular formats
FEA Model Updating
- FEA Model Physical properties on an FEA model are updated so that its FEA modes more closely match EMA modes
- Updated FEA properties: (Point mass, spring stiffness, viscous damping/Rod & beam cross sectional area & inertias/Rod & beam cross sectional area & inertias/Material elasticity, density, Poissons ratio)
- Exhaustive Search Evaluates 1000’s of SDM solutions for the
closest match of mode shapes - Local regions of a structure can be selected for FEA property updating
- FEA & EMA mode Pairs are selected for ranking the closest matches
- Export of updated FEA model in popular FEA formats