Energy Store and return

[kukogoba]

I am making a research in the field of prosthetic foots and i want to study how the prosthesis stores and returns the energy due to the strain energy.
Which kind of analysis should i run? Dynamic? Static?
Which outputs should i active?
It´s supposed that when the prosthesis touches the ground the energy begins to store, this energy stored should be maximun when the deformation is maximun too. Then the energy is returned to inpulse the foot forwards.
I think that i have to analyze what percent of this energy is lost, and make it minimun.

 

[IceBreakerSours]

Take these comments with a bag of salt:

You will have to think about what the purpose of the prosthetic is, what the expected use is, who the average person might be, .. .. .. to decide a number of things for this project (including which type of analysis to use). In general, I would think a dynamic analysis (implicit or explicit) would be the way to go. Unless I am mistaken, you sound like a beginner given the way you have framed your questions, I will suggest implicit dynamic solver. If you have never used implicit dynamic solver, you should be *very* careful about what you are stepping into and spend a LOT of time preparing for dynamics.

Another note: You will have to pay attention to any dissipatory mechanisms (viscoelasticity, damping, hysteresis, etc.) of the materials more than anything else because friction between the prosthetic and the ground may be out of your control (unless it is!) but friction between joints in the prosthetic may also be under your control (as part of design iterations).



*********************************************************
Are you new to this forum? If so, please read these FAQs:

http://www.eng-tips.com/faqs.cfm?fid=376

http://www.eng-tips.com/faqs.cfm?fid=1083

 

[kukogoba]

Yes, you are right in everything. I´ve started working with Abaqus recently. Even more with dynamic analysis. I´ve read a lot of theory, but i know that ít´s not enough.
Up to now i´ve done lots of static analysis to get the stresses and displacements. Once i´ve defined the geometry of the prosthesis i want to start with dynamic analysis (if they are necessary). I´ve defined 3 phases. Heel strike, mid-stance, and toe-off. In the static analysis i´ve studied each phase separately. Do you think that could be possible to make an case that involves the 3 phases?
The prosthesis is made of carbon fiber - epoxy. Where could i find the data you told me (visco, hysteresis,...).
Any information is very valuable for me. Thanks al lot!!!

 

[IceBreakerSours]

Your questions are making me nervous for you and the project. These sorts of questions should be answered by people around you or your own literature review or course-work.

*********************************************************
Are you new to this forum? If so, please read these FAQs:

http://www.eng-tips.com/faqs.cfm?fid=376

http://www.eng-tips.com/faqs.cfm?fid=1083