Hello Peter,

According to you I have given revolute joint between the shaft and bearing, replace spring in place of chain and real spring and assign gravity, added fixed joint to the bolt hole of the base plate, gave pretension to all the bolts and give two equal and opposite force to both side face of muscle and also force(i.e load of weight) at the weight hung below. but its showing error(shown below in figure). I could not recognize my fault. Can you help me to solve it?