Hello Everybody

I need help setting up a torsional spring. Heres the deal, I have 2 disks and im applying torques in opposite directions on each disk with a torsional spring in between. So the sum of the torques 3 torques (bottom disk, spring, and top disk) should be zero. However everytime I run the simulation all three have the same values. To understand it a little better I used the linear spring example with two blocks, summed up the forces, and they equaled zero. This led me to believe that I have set up the torsional spring incorrectly. How exactly do you set up a torsional spring between two disks? Both linear and torsional examples are attached

Any help would be GREATLY Appreciated,

Thanks!!

You got the answer you should have gotten. The sum is not zero because the disks rotate in opposite directions so if the sping is relaxed at start, it loads up as the disks rotate opposite each other and then returns to zero when the disks return to their start positions. If you expect the sping torque to be zero, then the disks have to keep the same relative position to each other and rotate together in the same direction. what should be equal is the spring force and reaction force whenever the parts are static.

In your linear example, the sum of the three forces is not zero. Take for instance the values at 1.5 seconds, the three forces ar -4, -3.5 and +3.5 which do not add up to zero.