Modal Analysis

The fundamental behavior of a structure is revealed by its vibration modes. The Modal Analysis add-on brings your structural model to life and calculates its unique vibrational behavior.

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Modal analysis results of a container structure in RFEM showing color-coded vibration modes of walls and supporting steel frame.

Discover Modal Analysis for RFEM 6

The vibration behavior of a structure can dominate its response to dynamic excitations, such as machine-induced vibrations or tectonic events. The Modal Analysis add-on determines the fundamental properties of your structural model, including its natural frequencies, its periods, and the associated mode shapes.

Using the calculated vibration periods and shapes, you can estimate the structure's dynamic behavior and determine if resonance becomes critical. These results also feed directly into the Response Spectrum and Time History Analysis add-ons for further seismic and time-dependent investigations.

Calculation of eigenvalue, angular frequency, natural frequency, and period
Visualization and animation of mode shapes
Selection of several mass matrix options, including user-defined degrees of freedom
Documentation of numerical and graphical results in a printout report

One Analysis, All Subsequent Results

With modal analysis, you only need to calculate the eigenvalues and mode shapes of your model once. Then, they are fed directly into the response spectrum and time-history analysis without requiring you to re-enter the data.

Automation for Standard Compliance

Methods that automatically determine the number of modes aim to efficiently calculate the modal mass factor required by seismic codes, eliminating the need for manual trial and error.

Masses as Defined in Your Project

You can derive masses directly from load cases and load combinations or add node, surface, and line masses manually. In either case, the masses are incorporated directly into the eigenvalue solution.

See Behavior, Not Just Numbers

The animated graphical modes and comprehensive result tables make it easier to identify the truly relevant modes early on, before proceeding with the design.

The Modal Analysis add-on provides access to a structure's dynamic properties and lays the groundwork for dynamic analyses, including seismic design, resonance checks, and structural modifications. Some relevant use cases include:

RFEM model of a steel staircase truss structure displaying mode shapes and natural frequencies from the Modal Analysis add-on.

Vibration Analysis of Multistory Reinforced Concrete Buildings

Analyze natural frequencies and mode shapes of high-rise concrete structures under self-weight and seismic mass combinations in order to identify the critical vibration modes for seismic design.

Natural Frequency Analysis of Steel Frame Industrial Structures

Determine natural frequencies and modal shapes of complex steel frames with varying boundary conditions to avoid resonance with operational loads.

Mode Shape Evaluation for Container and Modular Structures

Compute mode shapes and participation factors of container-type structures, including added equipment masses, in order to assess their dynamic behavior and guide design modifications for vibration mitigation.

Dynamic Validation of Structural Modifications After Stiffness Changes

Simulate structural stiffness alterations and perform a modal analysis to compare mode shapes and natural frequencies before and after design changes to trace the effects on vibrational performance.

Calculation of Modal Analysis

Defines mass sources from load cases or load combinations and calculates eigenvalues, natural frequencies, and mode shapes for dynamic evaluation.

Visualization of Mode Shapes

Shows animated and static mode shapes in RFEM/RSTAB. Clear, visual results make it easier to identify critical dynamic behavior.

Integration into Further Analyses

Automatically transfers the calculated modal properties to the response spectrum or time-history analysis, ensuring consistent dynamic analyses.

Response Spectrum Analysis — Reaching Effective Modal Mass

See how automatic mode-count settings in Modal Analysis help you achieve the effective modal mass factor required by your seismic code — without manually adding modes.

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Color-coded modal analysis results of a multi-story building model showing vibration modes of slabs, walls, and columns in RFEM.

Related Technical Articles

Modal Analysis in RFEM 6 Using Practical Example

Modal analysis is the starting point for dynamic analysis in RFEM 6. Determine natural frequencies, mode shapes, and modal masses to support vibration design and further dynamic analyses.

RFEM 6 workbench showing 3D wireframe model, modal analysis results, effective modal masses and natural frequencies in printout report.

Methods for Determining Number of Mode Shapes in Modal Analysis Add-on

This article explains various methods in the Modal Analysis add-on for determining the number of mode shapes, helping you balance accuracy with computation time.

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Unlock the full potential of Dlubal software with powerful programs like RFEM, RSTAB, RWIND, and RSECTION. Try them for free and see how easy it is to model, analyze, and document even complex structures. Our experts are ready to guide you through a short online demo tailored to your industry.

Yes. The add-on integrates directly into RFEM 6 and RSTAB 9 with guided mass and load case definition, so you can compute modal properties even if you are not a dynamics specialist.

Yes, the computed natural frequencies and mode shapes can be used as input for response spectrum and time history analyses, which support code-compliant dynamic design checks.

Yes, you can assign additional nodal or surface masses to account for non-structural elements, which will yield more realistic dynamic properties.

Yes, it animates and displays modal shapes in the RFEM/RSTAB graphical view. This helps you easily interpret how the structure deforms at each frequency.

The add-on generates participation factors and effective modal masses, which allow you to identify the modes that contribute the most to the structural response within your frequency range.

Yes, you can use predefined load cases to automatically derive mass contributions, which saves time and ensures consistency with your structural model definitions.

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Calculate Your Price

Product

Purchase Type

Quantity

1,510.00 USD

Service Contract

+110.00 USD

Total Amount 1,620.00 USD

Online Manual

Browse the online manual chapter on Modal Analysis to find detailed background on every setting and result.

Videos

Watch short videos showing Modal Analysis features and workflows in action.

Webinars

Access recorded webinars on Modal Analysis whenever it suits you, and keep learning at your own pace.

Modal Analysis

Discover Modal Analysis for RFEM 6