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Using own coupler 3D models

PostPosted: Sun Jan 15, 2017 10:57 pm
by Sanrag
I have modelled my own model of a Tight-lock coupler in solidworks. I would like to know if it is possible to change the coupler in the default wagon model and replace it with my own model with rest of the wagon remaining unchanged.
If it is possible could you please briefly outline the procedure to do the same.

Re: Using own coupler 3D models

PostPosted: Tue Jan 17, 2017 7:33 am
by Roman Kovalev
It depends on what exactly you are interested to simulate. Usually if you want to simuate the coupler itself you probably do not need cars, just two couplers that would let you to simulate basic operations. When we simulates vehicles and trains we usually do not consider detailes coupler / draft gear models. In that case we use simplified model that let us quite accurately predict longitudinal train dynamics without detailed analysis what is really going on in couplers. To give you any indtructions I need to understand what you want and expect from such simulation? What is your plan and what kinds of characteristics you would like to check?

Re: Using own coupler 3D models

PostPosted: Tue Jan 17, 2017 7:50 am
by Sanrag
I am trying to study the effect of coupler slack and the friction between couplers on the longitudinal dynamics of a train. I am trying to address if the coupler features are causing any jerks in a train. And for that I need to consider the exact model of a H-type tight lock coupler.

Re: Using own coupler 3D models

PostPosted: Tue Jan 17, 2017 4:26 pm
by Roman Kovalev
I believe that you need to use a typical train model that considers every car as a body with one longitudinal d.o.f. In UM we use UM Train module for that. I think you do not need detailed (part by part) simulation of couples/draft gears. You may consider the model more generally as a force function with given slacks and deflection-force diagram.

UM Train is briefly described on our web site here: http://www.universalmechanism.com/en/pl ... x.php?id=3
Here is the UM Train user's manual: http://www.universalmechanism.com/downl ... _train.pdf.

Slacks in draft gears and its force diagram influence on the longitudinal train dynamics. It is true. We recently publish a paper where we considered longitudinal train dynamics including slacks in draft gears and its experimental force diagrams. That paper is presented here: http://www.universalmechanism.com/en/ne ... php?id=123. There is a link to download the full paper. If 50 free downloads is already exhausted, just let me know and I will share it with you.

Re: Using own coupler 3D models

PostPosted: Wed Jan 25, 2017 5:19 am
by Sanrag
I am trying to simulate basic operations with just 2 couplers. When I switch on the 3D contact and try to open the simulation window, UM simulation hangs. Could you please tell what should be done to avoid it.

Re: Using own coupler 3D models

PostPosted: Wed Jan 25, 2017 9:15 am
by Roman Kovalev
Oh, it is very difficult to say something definite. The only suggestion I can give you is to turn off all contact pair and turn it on one by one to check what exactly makes the simulation so slow. Please see the attached snap shot.