To me it looks like an iterative process with fixed number of iterations, where on each iteration each point is moved along the net force vector.
yes that's it at the moment. i calculate for each vertex the sum of all its edge vectors as force.DeepSOIC wrote: ↑Sat Nov 11, 2017 9:35 pmTo me it looks like an iterative process with fixed number of iterations, where on each iteration each point is moved along the net force vector.
in the simplest case the force is the hooke force if a line is longer than mk = 2,bernd wrote: ↑Sun Nov 12, 2017 12:42 pmStill I do not really understand what data do you input, and what you would like to analyse. Since it is sketch based I assume all members are in a plane. Furthermore rubber usually behaves highly nonlinear when leaving linear stress, strain range. In which range are you? Your edges are staight, but rubber usually has no bending stiffness. What do you assume?
Code: Select all
f=0.01 for n in g2.nodes(): nbs=g2.neighbors(n) v0=g2.node[n]['vector'] r=FreeCAD.Vector() for nb in nbs: mk=2 tf=g2.node[nb]['vector'] -v0 if tf.Length > mk: fac= 1.0*(tf.Length-mk)/mk tf=tf * fac else: tf= FreeCAD.Vector() r += tf (a,b)=list(conix[n]) rc=sk.movePoint(a,b,v0+ r*f,0) g2.node[n]['vector2']=v0+ r*f rc=sk.solve()
cool stuff,microelly2 wrote: ↑Sat Nov 11, 2017 1:32 pmI'm looking for a ready to run method to simulate the tension forces in a rubber band network
the force is proportional to the lenght of a segment (hooke)
I pin some points (in the vide I use arcs to mark them)
the network is a sketch object with coincidence constraints only and the fixed positions of the pinned points.
is there a fem module and a tutorial how to get this running?
thanks for a tipp.