Reverse Engineer a sheetmetal formed shape based on load

[tmalinski]

I am a SolidWorks user and am looking to see if UG or any other higher end package can short cut some development time.

I need to develop a pair of formed sheetmetal leaf springs. The blanks are .030 thick x .125 wide x 1/2 long 301 FH stampings. They each have an s curve shape formed along their length. When assembled the two springs lay on top of each other and a load is applied. Obviously I could go thru a trial and error development process out on the floor to figure out what their free shape is, but I am looking for a CAD system to do this for me, at least get me close.
I want to constuct the leaf spring models in an assembled loaded state and then tell the system what the applied load is. Then I want the Cad system to actually modify both models to their calculated free state.
Is this possible?
tom

Tom Malinski

http://www.okayind.com/

Dell Prec 670, Xeon 3.8,2GB Ram, Nvidia Quadra FX 3450/4000 SDI
SWorks Pro & PDMWorks 2007 SP3.0

 

[JohnRBaker]

If you know the spring rate, you should be able to do that with Deformable Parts and Expressions. However, if you don't know the spring rate, you'll probably have to use somesort of FEA process, but that could still be done by hooking it up to the Optimzation Wizard.


John R. Baker, P.E.
Product 'Evangelist'
NX Design
Siemens PLM Software Inc.
Cypress, CA

http://www.siemens.com/plm

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

 

[tmalinski]

Thanks for your reply, So are you saying that UG can do this? out of the box, or any add on software required? My boss is toying with the Idea of purchasing a higher end system if it will do this (we have SolidWorks now) We actually have many stamped products with similar development requirements. So the ROI could be worth the expense of a seat and training.

Tom Malinski

http://www.okayind.com/

Dell Prec 670, Xeon 3.8,2GB Ram, Nvidia Quadra FX 3450/4000 SDI
SWorks Pro & PDMWorks 2007 SP3.0

 

[JohnRBaker]

The use of Exprssions linked to Deformable models is incuded in the basic modeling bundles, however the FEA and Optimization Wizard will either require a different, more advanced bundle or else you could purchase them as add-on modules to a basic bundle, but it's usually more exconomical to purchase the bundle that has all of the modules that I need since you get a cost benefit due to them being sold as a single bundle to start with.

If you wish to look at the suite of porducts available in the NX family of products, go to:

http://www.plm.automation.siemens.com/en_us/products/index/index.shtml

For imformation about the bundles available and their prices, please contact either your local Siemens PLM Software sales & support office which can be found at (just select on the map what part of the world that you're lcoated):

http://www.plm.automation.siemens.com/en_us/about_us/contact/sales.shtml

Or you can contact one of our regional offices for more details:

http://www.plm.automation.siemens.com/en_us/about_us/contact/index.shtml

Or you could request more information online at:

https://www.plm.automation.siemens.com/forms/request_info/

I hope this helps and that you will follow-up with one of the suggestions above.




John R. Baker, P.E.
Product 'Evangelist'
NX Design
Siemens PLM Software Inc.
Cypress, CA

http://www.siemens.com/plm

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

 

[tmalinski]

Thanks for your help
Tom

Tom Malinski

http://www.okayind.com/

Dell Prec 670, Xeon 3.8,2GB Ram, Nvidia Quadra FX 3450/4000 SDI
SWorks Pro & PDMWorks 2007 SP3.0

 

[hudson888]

The way I see it Tom you could be trying to do one of two scenarios.

The first case would be that you have reasonable amounts of clearance and no real timing issues with how the overall mechanism is going to work. The analogy would be that you have a car with leaf springs which you want to make so that they work to give you a desirable ride height at kerb, (or do you spell it curb). Anyhow you just want to know two conditions how it is made and how it sits under a range of loads. In this case you can do the calculations using expressions, a spreadsheet within NX, or some other calculator outside of NX and just plug in the results later on. Most applications are like this, and you would use deformable parts to show the springs working at different heights. NX can help you to do that out of the box.

The second case is the one where you need to do a bunch of real time work, so that if the spring rate isn't progressive and you have to know precisely where one part is going to be in relation to another so that a mechanism is tripped at a precise time, or a clash is avoided. Then you need to either look at some add on licenses and/or do some extra programming. If you need to analyze material properties and deformation by means of FEA then that is one reason to look beyond standard NX. Then if you have additional elements of the mechanism that you need to input that can't simply be done by iterating with mating conditions then you may need to look at the motion license.

Most of the time it is the first case and you just need a few tips and tricks to set things up so you can get enough info to to the job without needing to go any further.

Best Regards

Hudson

 

[tmalinski]

Thanks Hudson,
What does deformable parts mean in UG? I'm assuming it's more than just an unfolded (flat blank) of a sheetmetal part. In my example the leaf springs "S" curved shape actually decrease their bend radii and relative position to each other as the load decreases to a free state, (the spring becomes more bent). This is why this can be more challenging than it seams. Just to clarify, as the leaf springs unload the s curves of each spring remain tangent to each other but the center distance of the radii and the radii sizes change / get smaller. Although SolidWorks can not do this automatically, if I manually modified the model I would use configurations to save the various states (loaded / unloaded) within the same assembly. I'm assuming UG has something similar to configurations the difference being it would automatically calculate the unloaded shape and update the model for me.
Tom

Tom Malinski

http://www.okayind.com/

Dell Prec 670, Xeon 3.8,2GB Ram, Nvidia Quadra FX 3450/4000 SDI
SWorks Pro & PDMWorks 2007 SP3.0

 

[JohnRBaker]

A 'Deformable Part' is a parametric model that is created in one state (one set of parameters) but which can have, in the context of an assembly, a different set of parameters applied to it. A simple example would be a coil spring where it's modeled based on its free length yet when added to an assembly you would apply an as-assembled length. Now this new length, which will only have an affect on the model in the assembly, meaning that it will not effect the original in anyway, which also means that you do NOT need 'Write access' to the original since ALL of the updated parameters are assigned and stored in the assembly where the spring is installed.

Now as to the automatic nature, that's up to how you derive those parameters in the assembly, which could be calculated from a formula or measured from features of the assembly. For example take, that coil spring. You could measure the distance between the two mating faces where the spring will be installed and that distance applied to the spring as its new length. As the distance between the parts change, so does the length of the spring.

Referenced below is a video clip of a demonstration showing how coil springs can update as the distance between their mountings change. Note that the 3 coiled springs are the exact same part model and that the length of each one is determined by the requirement of their particular assembled position, independent from the others. And for the record, this capability has been part of NX since NX 1, or for about 5 years now.


John R. Baker, P.E.
Product 'Evangelist'
NX Design
Siemens PLM Software Inc.
Cypress, CA

http://www.siemens.com/plm

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

 

[hudson888]

Tom,

What you should know about deformable parts is that there are several posts explaining how it is done that you can search for on this forum. And most importantly you can deform several different component instances of the spring as loaded to an assembly and change them by different amounts. Very useful indeed. You may be able to pick this up from the video, but it may not be immediately obvious, so I thought it should be mentioned.

Best Regards

Hudson