# Visual SDMTM

### VT-540

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.

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:

1. Count the number of modes using a Mode Indicator function
2. New Modes are quickly calculated that show the effects of multiple modifications
3. 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
4. Many “What If” cases Fast calculation allows many potential modifications to be explored

## Visual SDMTM Features

• 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
• 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
• 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 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

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