FEMtools Dynamics

Advanced Finite Element Solutions for Simulating Dynamic Response and Structural Modifications

FEMtools Dynamics contains tools for:

Complex modes analysis.
Frequency response function (FRF) analysis.
Harmonic response analysis.
Residual vectors.
Superelement analysis.
Structural dynamics modification (modal solver).
FRF-based assembly (FBA).
Time domain simulation.

Complex Modes Analysis

Key Features

Use integrated FEMtools sparse solvers or pilot external FEA solvers.
Lanczos complex and Hessenberg modal solvers.
Support for various types of damping (modal, proportional viscous and structural damping, viscous damper elements, material damping).

Frequency Response Functions (FRF)

To obtain FRFs, the response function is divided by the excitation force. Because these functions do not contain force information, they only depend on mass, stiffness and damping properties of the structure, just like the modal properties. Therefore they are also suitable as responses for correlation analysis, sensitivity analysis and model updating.

Key Features

Compute FRFs that are directly comparable to experimentally obtained FRFs.
Use integrated FEMtools sparse solvers or pilot external FEA solvers.
Modal and direct solvers.
Padé approximant method for fast solution.
Residual vectors (inertia relief, viscous damping and applied loads).
Modal FRF synthesis using from FEA or test modes.
Support for various types of damping (modal, proportional viscous and structural damping viscous damper elements, material damping).
Support for local coordinate systems.

Harmonic Response Analysis

In harmonic response analysis, the excitation is defined in the frequency domain. All of the applied forces are known at each forcing frequency.

Key Features

Operational shapes analysis using modal and direct solvers.
Displacement, velocity or acceleration responses functions at selected DOFs.
Enforced motion excitation.

Residual Vectors

Residual Vectors (RESVEC) are used to extend the modal base that is used for modal frequency response methods. They can compensate the effects of modal truncation and often improve the dynamic response without the need to increase the number of mode shapes or use a direct method.

Superelement Analysis

A superelement is defined by grouping a number of elements and solve for this substructure separately. Superelements offer great time-savings in application that require significant re-analysis like time-domain and frequency domain responses analysis, design
optimization, probabilistic analysis, robust design and multi-body simulations. Superelements are also used to overcome situations where a full solution is not even possible because of limited computer resources (internal memory, disk space).

Key Features

Integrated Craig-Bampton matrix reduction.
Easy definition of superelements using sets of elements or sets of nodes.
Support for assemblies without residual model.
Automatic generation of master DOFs and processing of DOF relations.
Support of slave DOFs in DOF relations as master DOFs of a Superelement.

Structural Dynamics Modification (SDM)

Structural Dynamics Modification (SDM) is a modal domain method to rapidly assess the influence of many structural changes on the modal parameters and derived results like FRFs or operational shapes. This technique can be used to investigate the effect of different modeling assumptions on the level of correlation with test data. Other applications are in vibration troubleshooting or are design-oriented, for example to find the most efficient structural modification that will shift resonant frequencies away from excitation frequencies.

Key Features

Modification using finite elements that are added to a test model or a finite element model. An unlimited number of modification elements and types can be combine.
Point-and-click interactive definition of modification elements.
Solution of modified mode shapes and resonance frequencies using modal parameters coming from modal test or finite element analysis.
Slider control for all physical properties of the modification elements with real-time re-analysis and display of mode shapes, mode shape pairs, FRFs and operational shapes.
Correlation analysis between unmodified and modified models.
Variational analysis of all physical properties of the modification elements using the fast modal solver.

FRF-Based Assembly (FBA)

FRF-based assembly (FBA) is a frequency domain method wherein each subsystem is described in terms of Frequency Response Functions (FRFs) of the free-interface uncoupled systems and the FBA process computes the FRFs of an assembly from FRFs of individual components connected by joints and constrained by boundings. FBA is a computationally efficient method that focuses on the coupling between components and is therefore suitable for larger assemblies with many components and for studying the transmission of forces by the connections.

Time Domain Simulation

Time Domain Simulation (TDS) provides a set of tools to compute the transient response of structures in a computational efficient way. In combination with the modal parameter extractor, TDS can be used in a pretest analysis phase to set-up an operational modal analysis test.

Prerequisites

FEMtools Framework with basic FEA Solvers (included)

Options

Upgrade to FEMtools Correlation
Upgrade to FEMtools Model Updating
NASTRAN interface and driver
ANSYS interface and driver
ABAQUS interface and driver
UNIVERSAL FILE interface and driver
FEMtools Modal Parameter Extractor
FEMtools Rigid Body Properties Extractor