Calculated Energy not equal to simulated energy

- January 24, 2024 at 11:22 am
  
  Aaron Dang
  Subscriber
  
  I'm working on my thesis and my calculated energy is not even close to my simulated energy.
  Context: I am simulating a collision using Explicit Dynamics. I am modeling the parts in Solidworks and converting them into .step and then importing into ANSYS for simulation. Theoretically, the total energy of the system should be equal to 1/2mv^2 as i have a moving part collide with a fixed position part.
  Moving Part:
  Stationary Part:
  Ansys says the mass of the moving object is 0.915kg and the object has an initial velocity of 6m/s. Combined they equal 5.5147J of energy. However, plugging the mass and the velocity into 1/2mv^2 yields 16.483J. My question is where am I going wrong and why is there such a large discrepency? I should also mention that I mated the parts so that they are touching. As far as I know, they are still 2 distinct parts.
  Even if the answer isn't found, I would at the least like a plausible explanation of the issue. Thanks for any input.
- January 25, 2024 at 2:11 pm
  
  Ram Gopisetti
  Ansys Employee
  
  Hi Aaron,
  I am not sure what you are doing here, but consider that the perfect eastic collision between two spherical objects with 4.11025039e-003 kg and 10 m/s should produce 0.205 J of KE.
  If you check the KE trackers, I got the same except with some numerical error, which can be tightened with mesh e.t.c
  Since the momentum is not fully transferred because of the time for ball 1, you are seeing peaking, but for ball 2, with the initial velocity applied, you see it started at 0.196 so it is working as it needed to be. Check your setup.
  Cheers, Ram