×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

What does (dW/dt) =0 ( where W is the external work) indicate.?

What does (dW/dt) =0 ( where W is the external work) indicate.?

What does (dW/dt) =0 ( where W is the external work) indicate.?

(OP)
I am running ElastoPlastic analysis. With application of the load, the external work of the whole model at a specific time reaches a peack and starts to become a decreasing function of time, although the load is increasing. After that the external work becomes a decreasing function of time.
I do not understand the underlying physical cause for this outcome.
My energy equation
E(external force)= E(elastic)+ E (plastic dissipation)+E(artifical damping)
thanks for help

RE: What does (dW/dt) =0 ( where W is the external work) indicate.?

Is the dominant load tensile?  Are the members thinning as they elongate?

RE: What does (dW/dt) =0 ( where W is the external work) indicate.?

(OP)
No my material (soil) only takes compression

RE: What does (dW/dt) =0 ( where W is the external work) indicate.?

Soil??
I wouldn't have said that it actually falls into a "material type" which exhibits elastic/inelastic properties.
I would almost certainly think your analysis concept is flawed. Describe your load/reaction system (i.e explain whats going on and how) and we might be able to give better guidance.

RE: What does (dW/dt) =0 ( where W is the external work) indicate.?

(OP)

Please read my explaination and give me your physical opinion
I have total load applied on a mixture porous medium (Soil solid matrix and water), which is partially drained. Initially, when the dW/dt>0, the total load is being carried by both the solid matrix and water. However, most of that load is carried by solid matrix as the pore water pressure is being dissipated at this stage (water is leaving the sample).Later on when the sample porosity becomes small due to consolidation and with increasing the load, the water will be confined within the sample (undrained case will prodominate) and the total load will be mainly carried by water : the external work will be transfered to pore water pressure without generating any stress in the solid matrix
  

RE: What does (dW/dt) =0 ( where W is the external work) indicate.?

Ok, so what is your analysis trying to show? Or what are you wanting out of it?

RE: What does (dW/dt) =0 ( where W is the external work) indicate.?

I think the integrated energy balance is Etotal=constant.
 
If the external work reaches a plateau (dW/dt=0) it means the supports of the external loads have zero displacements.

Maybe after a while, the structure becomes incompressible.

RE: What does (dW/dt) =0 ( where W is the external work) indicate.?

(OP)
Thank you xerf

RE: What does (dW/dt) =0 ( where W is the external work) indicate.?

xerf ..why the structure becomes incompressible when dW/dt=0.

RE: What does (dW/dt) =0 ( where W is the external work) indicate.?

It was just a guess based on....

"...and with increasing the load, the water will be confined within the sample (undrained case will prodominate) and the total load will be mainly carried by water."

 

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources