Dynamic Clearance Analysis: What is the best method?

[EDykstra]

Hello everyone,

I have been tasked to determine the best solution for doing dynamic clearance analysis for machine assemblies. We have asked UGS to give us a demo on how best to achieve this, (ClearanceDB and ‘Total Digital Validation’ among others) but I am soliciting feedback from others too, hence this post.

I know that our assemblies are not really that big (approx 2,000 unique parts at various quantities for a total of 20,000 parts) especially when compared to an aircraft. So, maybe the appropriate solution is going to be different. But, can you share your experience with me? Should the solution be JT based, or NX? What functionality should we plan for – using mechanisms and automatically converting mating conditions to joints etc?

I think the people here expect to be able to dynamically move the sub assemblies of the machine sections and see color changes etc when there are collisions etc.

I expect that any solution will require changes to how the files are prepared. We can’t make those changes for all part files, and the value added comes from the higher level assemblies anyways – so I expect a solution will start at the top level assembly, and we will push it down further as time progresses, to catch issues earlier.

Thoughts?

Thanks in advance for your feedback.

Eric

 

[JohnRBaker]

If you are faithful in applying Mating Conditions and you're not interested in true Kinematic/Dynamic motion analysis, you could also use Assembly Sequencing which will allow you to assign a 'motion' to any element of an assembly and ask that it honor the mating conditions, which means that if they truly represent 'joints' and degrees of freedom, your entire 'mechanism' will articulate. And once you have that working you can set one of two types of collision detection. The first simply highlights the parts that interfere but the motion continues, while the second will halt the motion at the point of interference (there is an option to continue if you wish). Note that this is a simple 'hard interference' type check.

Note that this does require an Advanced Assemblies license.


John R. Baker, P.E.
Product 'Evangelist'
UGS NX Product Line
SIEMENS
UGS PLM Software
Cypress, CA

http://www.siemens.com/ugs

http://www.plmworld.org/museum/

 

[EDykstra]

John,

We experimented with sequencing. In NX 4, it is not always finding the interference. Further, in some cases, it finds an interference where there isn't one. This is with the same assembly. Now, it is likely a tolerance issue with size-on-size scenarios, but regardless, as you stated, it is a simple 'hard interference' check and you can't check that the 'clearance' is at least 40 mm for example.

The more I research the needs here, the more it leans to a ClearanceDB solution. For example, they would love to be able to set a rule such that power and data cables are always at least 100 mm apart etc.

Question: Can ClearanceDB also check that sub assemblies meet the rules through a range of motion? Or, are the rules checked against a static position? Is there an intermediate solution to this problem, or does it require going 'all the way' with ClearanceDB?

Thanks,

Eric