I need to model a "fishing rod" in 2 dimensions by joining several "rigid sticks" by flexible/elastic joints. The joints act as plate/torsion springs with different spring constants. The "fishing rod" will bend at these joints. The segments of the rod become lighter and the springs softer, towards the tip.
The only input data are the length and weight of each piece of rod and the respective spring constant by which it is attached to the previous one.
I wish to see how this object bends and moves when one end (the handle) is exposed to torque (i.e. how the fishing rod bends when you throw the bait. - There is no need to include torque around the object's own axis.)
(This is not a problem involving stress analysis by FEM. It is about movement in a time frame of seconds. I will later try to extend this model into biomechanics.)
I can follow (and have simulated) the Lagrange transform for the double pendulum, but for more than two segments, the Lagrange transform becomes "virtually impossible" to compute.
If I could just get a grip on how the "physics engine" for multiple, elastic/flexible joints work, in this kind of software, I could maybe use this to model the fishing rod.