Learning Forum

[Pranshu Kharbanda]

Hi all,

I am tring to study the effect of damping properties of epoxy adhesive on the output motion of the moving component from low to high frequencies (up to 800 Hz). This adhesive (~1 to 2 mm thick) sticks the energy supplying element to the moving component as shown below.

I have modelled in transient module of ansys currently as shown below, where the input load is supplied as a displacement controlled boundary condition (hence haven't modeled the energy supplying element). 

My question is what would be the correct approach to study the damping effect of epoxy on the moving component's output motion ?

Thanks.

[peteroznewman]

What material properties do you have for the epoxy? 

What material models are you considering to use for the epoxy?

[Pranshu Kharbanda]

 

 

Hi,

I am currently using the resin epoxy material from database and added damping factors to see the effect first. I am planning to read about the various material models available and how to experimentally obtain those parameters too.

But firstly, I want to form the methodology of doing this study. Also one key question being if transient module is suitable for the same?

 

 

[Pranshu Kharbanda]

hi all, any insights on the below? 

thanks

[peteroznewman]

While Transient Structural "can" compute the response to the input, it is very inefficient way to study damping effects. Firstly because the solution takes a long time to solve for just one frequency and secondly because it will take a lot of effort to convert the time history of the response to that one frequency into information about the damping effect and thirdly because you have to repeat that process for each frequency you want to know about.

A more efficient method is to use a Harmonic Response analysis where the analysis will sweep over all the frequencies of interest and the damping is more easily estimated.

I suggest you start by taking the free course on Harmonic Response.

[Pranshu Kharbanda]

 

Hi Peter,

Ok thanks, i am trying harmonic response analysis as suggested.

now i am trying to figure out as to why there is mismatch between the mode shape 1 frequency (3648 Hz) and the first natural frequency of the frequency response (~40,000 Hz). will go through some references regarding this.

 

[peteroznewman]

You have not provided enough information to help you figure it out. 

Maybe you should take the Modal analysis course?

[Pranshu Kharbanda]

 

 

Hi Peter,

I have attached the workbench file here (for forum), with version 2023R. have applied displacement loading to see frequency response of the moving component. overall trying to form baseline to study damping behavior as i had detailed in my first post in the discussion. Thanks