## General Mechanical

Topics relate to Mechanical Enterprise, Motion, Additive Print and more

#### Unable to solve the model

• Akshath Ghanti
Subscriber

This is a simulation of passing a mandrel through a plate with hole fitted with a split sleeve. Here are the details:-

Analysis Settings

Boundary Conditions

This is where it is getting stuck and exiting with an error.

Contact Details

• peteroznewman
Subscriber

Akshath,

The mandrel is 95% of the way through the hole and reached the point where the cylindrical part of the mandrel is all that is left in the last part of the hole. This means that all the deformation that would result in residual stresses has occurred and all that remains is to remove the mandrel.

The reason the Static Structural solver can't keep going forward is that a dynamic event occurs when the mandrel leaves the bottom of the hole. The elastic strain energy stored in the parts must be released but there is a sudden end to the mandrel. The Static Structural solve can't find a static equilibrium in the next time step.

I suggest you make the mandrel longer and symmetric and put a conical section on top of the cylindrical section. In that way, the elastic strain energy stored in the parts can be released gradually and the solver will find static equilibrium at each time step all the way past the point when the frictional contact opens up and all that remains is the residual stress in the parts.

Good luck,

Peter

• Akshath Ghanti
Subscriber

Thanks a lot Peter, I'll try that and I'll keep it posted.Â

• Akshath Ghanti
Subscriber

I've tried your suggestions, it is still giving me that error.Â

• peteroznewman
Subscriber

It may work if you take very small steps, or put a blend on the edge between the cylinder and the cone.

A different approach is to use the original pin and get the step to end where the cylindrical face is near the end of the hole by editing the displacement value, then use Contact Step Controls to Deactivate the frictional contact between the pin and sleeve in the next step. At the end of that step, it will be as if the pin was not there.