incomprehensible results in dynamic analysis

Mathias_20527

Hi guys,

I tried to validate my results of dynamic analysis tools by doing the following:
First I made a static analysis of a blocked shaft with a torque of 82,000 Nm. This load resulted in a force in the blockade of Fres = 330,000 N which created counterforces in the roller bearings of about F1trans = 43,000 N in the fixed bearing and F2trans = 290,000 N in the floating bearing. This result is correct.

After this I tried basically the same analysis but using the dynamic analysis tools. To avoid any oscillation of the entire shaft, which would result in oscillating forces inside the bearing, I introduced the load softly and continuously as I could. See the chart:

The max load of 82,000 Nm and all other constraints and contacts were exactly the same. So I assumed equal resulting forces inside the blockade and the bearings but this wasn't the case and I can't figure out why. The following spreadsheet shows how big the difference between static and soft dynamic analysis was. 

	static	dynamic
input
load/torque	82,000 Nm	82,000 Nm
output
Fres	330,000 Nm	390,000 Nm
F1trans	43,000 N	5,000 N
F2trans	290,000 N	360,000 N

 

 

 

Evan Brennan_20557

Hi Mathias,

 

Thank you for posting your question in the Community!

Would it be possible to share the model with me so I can investigate the setup/results more closely?

 

Evan