@haruspex Good question about the angle being constant. The angle of intersection should be constant for a given simulation, however the springs themselves may bend.
Using vectors sounds promising. I am not sure if the vectors (alone) would contain the necessary information given Young's...
Writing the Lagrangian for 3 masses and 2 springs in a line is easy.
KE=1/2(m*v^2)
L=KE(m1)+k/2(l1-(x2-x1))^2+KE(m2)+k2/2[L2-(x3-x2)]^2+KE(m3)
However, I wish to model non-linear linkages of the above 3 masses and 2 springs.
Suppose that the second spring (m2-m3) is angle θ away from the...