Jump to content
Sign in to follow this  
Guest

viscoelastic material simulation in radioss

Recommended Posts

Guest

Hi everyone, I need an urgent help from all of you. I am doing a viscoelastic material simulation in radioss using kelvin maxwell law. i have the material data in storage modulus vs frequency so i changed my data into g(t) vs t. now when i go for curve fitting the value of prony term gi is coming greater than one.. As i have read in abaqus manual that value of gi should be less than 1 ,, so my question is this theory applied with radioss also or I can use my prony term coefficient which are coming greater than one.Please clear my concepts regarding this or also as per radios can i take the no of prny term more than 5 during curve fitting,, clear my concpts regarding this


Share this post


Link to post
Share on other sites
Guest

i mannu,

There is no mention of this condition for the Kelvin Maxwell Law in RADIOSS

Is there a reason specified why this has to be less than 1 elsewhere?

See in help - Altair RADIOSS > Reference Guide > Starter Input > Starter Keywords > /MAT:
/MAT/LAW40 (KELVINMAX)

Share this post


Link to post
Share on other sites
Guest

The linear viscoelastic model in Abaqus is defined in the shear relaxation modulus as:

G(t) = Go{ 1 - Sum series (i=1, I=n) gi exp(-t/Taui)}

As you know Go is the instantaneous shear modulus which is the highest modulus value of the prony series at time = 0.0. After that all moduli should be reduced less numbers than G0 till they go to G-Infiniti and this occurs at t goes to infiniti. Therefore,
G-infiniti is called the long term modulus at t = inifinit defined by

G_infinit = Go { 1 - Sum series (gi)}

There is no way in above equation that gi will exceed 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
You are posting as a guest. If you have an account, please sign in.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...