December 1, 2019 at 9:52 pmAmin1372Subscriber
I am doing a project that I want to see the reaction force of a part of my model after applying sinusoidal force with different frequencies and constant magnitude. I was wondering if you could help me out and tell me which method ( harmonic response or transient structural) I should use.
December 2, 2019 at 12:12 ampeteroznewmanSubscriber
Sinusoidal loads over a range of frequencies is called Harmonic Response.
There are two ways of solving it. Direct (stand alone), where all the nodes are computed, or Modal Superposition (MSUP), where a Modal Analysis solution feeds into the Setup cell of Harmonic Response and the modes are used to compute the response. Modal Superposition usually takes less time to solve, but you have to make sure to include a sufficient number of modes to have an accurate solution.
Harmonic Response is a linear analysis, so you are limited to linear materials, linear contact, small displacement assumption. If you need anything to be nonlinear, then you have to go with Transient Structural, but that is a Time-History simulation not a Frequency-based analysis, so you have to input the periodic load as time-history and post-process the results to extract frequencies.
December 5, 2019 at 12:06 amAmin1372Subscriber
Thanks for your help. So it seems I need to use Transient Structural because of friction between some parts which makes the model nonlinear. I would appreciate if could help me out with my question:
December 5, 2019 at 12:06 amAmin1372Subscriber
I wanted to find the reaction force of some parts when I apply a 0.3N force with two frequencies of 30 and 120 Hz.
December 5, 2019 at 2:19 ampeteroznewmanSubscriber
I recommend you build two (or three) linear Harmonic Response models that will bound the range of potential outputs before you go with a nonlinear Transient Structural model.
You say you have frictional sliding motion between some parts. Build a first model where the parts are bonded and there is no sliding. Build a second model where there is No Separation Contact so the sliding is frictionless. The results from each model will be slightly different, and the frictional sliding solution will be somewhere in-between. If the difference between the two results is small enough to be unimportant, you don't need to go to the trouble of building, solving and post-processing the Transient Structural model.
A third optional model, if it makes sense in your particular case, is to have no contact where the friction occurs.
December 6, 2019 at 7:05 pmAmin1372Subscriber
Yes that's a good idea. Is it true to define 0.3 N as real , zero as imaginary force and 0 to 30 Hz (or 0 to 120 Hz) for frequency range ? and do I need to feed the Harmonic Response with Modal Analysis? if so, How many modes should I choose to be calculated?
December 6, 2019 at 7:37 pmpeteroznewmanSubscriber
Where did you get 0.3 N of force from?
What gives the force a periodic frequency and what determines the frequency?
If you use a Modal Analysis to precede the Harmonic Analysis, this post has information on how many modes to include.
December 6, 2019 at 7:47 pm
December 6, 2019 at 7:49 pmAmin1372Subscriber
This is my model which includes human teeth and a device which vibrates and applies force with magnitude of 0.3N and two different frequencies of 30 and 120 Hz.
December 7, 2019 at 1:00 ampeteroznewmanSubscriber
- You must be logged in to reply to this topic.
Boost Ansys Fluent Simulations with AWS
Computational Fluid Dynamics (CFD) helps engineers design products in which the flow of fluid components is a significant challenge. These different use cases often require large complex models to solve on a traditional workstation. Click here to join this event to learn how to leverage Ansys Fluids on the cloud, thanks to Ansys Gateway powered by AWS.
Earth Rescue – An Ansys Online Series
The climate crisis is here. But so is the human ingenuity to fight it. Earth Rescue reveals what visionary companies are doing today to engineer radical new ideas in the fight against climate change. Click here to watch the first episode.
Subscribe to the Ansys Blog to get great new content about the power of simulation delivered right to your email on a weekly basis. With content from Ansys experts, partners and customers you will learn about product development advances, thought leadership and trends and tips to better use Ansys tools. Sign up here.
- Solver Pivot Warning in Beam Element Model
- Saving & sharing of Working project files in .wbpz format
- Understanding Force Convergence Solution Output
- An Unknown error occurred during solution. Check the Solver Output…..
- What is the difference between bonded contact region and fixed joint
- User manual
- The solver engine was unable to converge on a solution for the nonlinear problem as constrained.
- whether have the difference between using contact and target bodies
- material damping and modal analysis
- Colors and Mesh Display
© 2023 Copyright ANSYS, Inc. All rights reserved.