Some question in the contactmodel API

Raheem Sterling_22160

Hi,

I introduced a contact model which in contrast to incremental procedure, the force and torque were allowed to be calculated at every moment, so the "contactResults.normalForce" here is "+=" or "=", it seems "+=F_n" is right for me. Does this mean that "+="  for "contactResults"is used for force chain, rather than the accumulating over time ?

Stephen Cole

Hi Raheem,

When you add to the forces I'd recommend using += for most cases.  If you are using the latest version of the API the chaining works per time-step only, so you don't get the sum of the forces over time rather the sum of the forces calculated in the individual components of the model at that time-step.

For example in the image above the forces are calculated in H-M model so using= or += doesn't change the result (unless the model sums the forces in more than 1 place), however that force is then passed to the rolling friction model.  

 

If the rolling friction used = then it would overwrite the forces calculated in H-M and just return the forces from rolling friction.  Using += returns sum of both to EDEM and uses that to calculate the forces for that time-step.  Next time-step they start at 0 and you then return the next set.

 

Regards

Stephen