What's the best open source FE code for nonlinear transient analysis of truss structures (preferably with Python interface)?

I would like to share with fellow mechanicians an educational iPad app I recently developed. The name of the app is Truss Me! and the main goal is to help students, all the way from high school to college, to build intuition on how truss structures behave. The video below highlights some features of the app:

The app utilizes state of the art simulation techniques to provide the most realistic behavior for the structures.

I really think it is a revolutionary app as it has the most realistic simulation engine you could possibly have (including geometric and material nonlinearities, plasticity, buckling, etc) while keeping the interface intuitive enough so even kids or less technical people can play and learn.

You can find more details about the app in the following link:

http://www.scientificmonkey.com/software.html

I hope you like it!

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Hi to all

I am analyzing a simple 2D truss with Abaqus/CAE as you see
it in the below picture. But I have trouble
in evaluating forces in each element ( each link of truss is an element). I use
several way to get this forces , first of all use free body cut , as you know
for this solution I must spent a lot of time to evaluate this forces for all
link and can't get tabular report for
each element.

Another way is using Nforc (Nodal forces of each element ) but
when I use it in the report file I were confused from the difference in the
resultant forces in the beginning and the end of an element , as you see in the
below picture that I highlight for element 1 in the Node 1 and Node 2.

Another way is create a new field to multiply Stress (S11) in each element to its
cross section area to compute the normal forces, but since the cross sections
of my truss has defferent value I don't know how can define a function for that
to know this.

Finally I completely confused and want you to help me, I ask
this question from everybody but they can't guide me. I hope I can find my question in a good forum
such as IMechanica.

Thank you...

Hi
I have a quite (i think) easy problem to solve. Its a truss bar problem that is connected with pins where I just need to investigate the displacment(u).
(its a triangle with a bar in the middle, upper chord is planar and the middle bar is vertical.)

My problem is just that i have never used any pin function in abaqus.

Since I am an alum of the University of Minnesota, when I was a PhD student I lived only a few blocks from the site of yesterday's catastrophic bridge collapse in Minneapolis. The statics analysis of a truss is almost the first thing learned by every undergraduate engineering student, and appears to be relevant here. It is interesting to see words like "fatigue crack" and "vibrations" in the news . In light of such events, never has there been a better time to step forward and emphasize the importance of mechanics in daily life! Each time we drive across a bridge we are relying on the engineers of years past to have done their job correctly. We can argue on this forum about the meaning of elastic modulus for a carbon nanotube , or what happens to dislocations in micropillar compression , but all around us macroscopic human-scale mechanics is in our lives, and unfortunately now also in the news. Perhaps in this case the engineers of the 1960s were a bit lax: the interest and faith in steel as a wonder material may have caused a lack of design redundancy that has now apparently taken many lives. I recommend the book "Why Buildings Fall Down " as a fascinating read and study of engineering/mechanics principles suitable for a lay audience... and I truly hope that in tragedy we are reminded of the fundamental importance of our great field of mechanics. There is an important educational lesson in this as well. Getting the basics "right" is not an option--human lives are on the line if we don't put significant efforts into training the next generation of bridge designers and inspectors. Mechanics is at the core of our modern existence.