# Amplitude based frequency response simulation in Abaqus

• Automotive
• Sam George
In summary, you can use Abaqus to analyze a part with a displacement applied to a node, but you have to use a base motion boundary condition or apply a force.
Sam George
TL;DR Summary
Enforce displacement in Frequency Response Simulation
Hi,

I have inputs like displacement of a driving mechanism and then the frequency of concern .

Displacement: 0.2 mm
Concerned Frequency: 100 Hz

I would like to evaluate a part with the input displacement applied to a node and not as base excitation.
It can be sweep over the frequency range 0-200Hz

How do we set it up in Abaqus, can we give amplitude in steps over the frequency range?

Please guide me with a link or syntax on how to proceed with the analysis setup.

Regards,
Sam George

Here’s a quote from Abaqus documentation (chapter about SSD analyses):

It is not possible to prescribe nonzero displacements and rotations directly as boundary conditions in mode-based dynamic response procedures. Therefore, in a mode-based steady-state dynamic analysis, the motion of nodes can be specified only as base motion; nonzero displacement or acceleration history definitions given as boundary conditions are ignored, and any changes in the support conditions from the eigenfrequency extraction step are flagged as errors.

So you have to either use a base motion BC or apply a force instead.

Sam George and berkeman
FEAnalyst said:
Here’s a quote from Abaqus documentation (chapter about SSD analyses):

It is not possible to prescribe nonzero displacements and rotations directly as boundary conditions in mode-based dynamic response procedures. Therefore, in a mode-based steady-state dynamic analysis, the motion of nodes can be specified only as base motion; nonzero displacement or acceleration history definitions given as boundary conditions are ignored, and any changes in the support conditions from the eigenfrequency extraction step are flagged as errors.

So you have to either use a base motion BC or apply a force instead.
Thanks for the reply, I think I will have go with using Force.

## 1. What is amplitude based frequency response simulation in Abaqus?

Amplitude based frequency response simulation in Abaqus is a technique used to predict the dynamic response of a structure or system to a given input frequency. It involves analyzing the amplitude of the response at different frequencies to understand how the structure will behave under different loading conditions.

## 2. How does amplitude based frequency response simulation work in Abaqus?

The simulation works by applying a sinusoidal load at different frequencies to the structure and measuring the amplitude of the response. This data is then used to create a frequency response curve, which shows the relationship between the input frequency and the amplitude of the response. Abaqus uses finite element analysis to accurately predict the dynamic behavior of the structure.

## 3. What are the benefits of using amplitude based frequency response simulation in Abaqus?

Using this simulation technique allows engineers to understand how a structure will behave under different loading conditions, helping them make informed design decisions. It also helps identify potential resonance or vibration issues and can be used to optimize the design for better performance and durability.

## 4. What types of structures can be analyzed using amplitude based frequency response simulation in Abaqus?

This simulation technique can be applied to a wide range of structures, including mechanical components, bridges, buildings, and aerospace structures. It is particularly useful for structures that are subjected to dynamic loads, such as wind, waves, or vibrations.

## 5. Are there any limitations to amplitude based frequency response simulation in Abaqus?

While this simulation technique is a powerful tool for predicting dynamic behavior, it does have some limitations. It assumes that the structure is linear and that the material properties remain constant throughout the analysis. It also requires accurate boundary conditions and loading inputs to produce reliable results.

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