Hanging Lamp Shade, Generative Design

[Anonymous]

Hi!

I would like to do a lamp shade as a generative design in Fusion 360 with two fastening points.

The only structural force subjected to the lamp will be it's own gravity that will applied on the two points.
How will I apply a "counter gravity" structural force when I don't know the final weight of the object?

[pawel.potyrala]

Hi @Anonymous,

welcome to the Fusion 360 Community Forum! Thanks for posting!

For clarification, is the load from the generated lamp shade to be used in the design of the lamp itself?

If it is just the lamp shade with its dead weight that you would like to simulate, perhaps it is sufficient to make sure that the gravity load is activated (see: Apply the Gravity Load) and apply the constraints accordingly (see: Add the Constraints) at the fastening points?

Let me know if that helps. Thanks!

Best regards,

[Anonymous]

Hi and thank you!

Yes exactly, I have the gravity load activated and have set up a structural constraints at the fastening points.

But the program doesn't let med generate unless I set up a structural load as well.
In my case I don't have structural load besides the down pull of gravity on the object which is dependant on the mass that I don't know since I want it to be generated by the generative design.

[TrippyLighting]

I think @MikeSmell_ADSK should be able to answer that question. Interesting application!

[pawel.potyrala]

Hi @Anonymous,

apologies for the late reply. I involved a GD specialist that should be able to help you further.

You can already try the following:

• Put a minor load that will not significantly influence the results (~ .005 N or similar) to allow the calculation
• Begin with a starting shape and use the option to "Maximize stiffness" instead of "Minimize volume" to give the software somewhere to start.

Let me know if that helps. Thanks!

Best regards,

[MikeSmell_ADSK · Accepted solution]

Hi @Anonymous - 

Reading this thread, I get the impression that you may be using generative design more from an aesthetics point of view, rather than pure performance. I am also assuming that what you are designing is the support structure for whatever media you will be using to create the shade, i.e. paper, fabric, etc.. In this scenario, you will need to put some extra thought into the setup for an exercise like this, as gravity load only is not an acceptable setup and generative design is best suited for performance based problems with more complex loading scenarios. A few things to think about, that will allow you to move this along. 
1. Consider any non-service type of loads, i.e. handling of the lamp shade out of the package, or to install. 

2. Some small dummy loads to create some stress in the system. 

In the following images, I did a small compressive force in one load case, and then another load case with forces that would create a bending moment about the vertical axis of the lampshade. These were on the order of magnitude of a couple pounds. You will see, it creates a very minimal design. The direction of the loads and respective magnitudes will influence the shape significantly, so you will definitely want to do some experimentation with your load cases. 

I hope this helps. 

Mike Smell - Product Manager, Fusion 360 - Generative Design

[TrippyLighting]

@MikeSmell_ADSK Great post! Thanks!

[mickey.wakefield · Accepted solution]

I worked on this a bit as well....my explanation is similar to Mike Smell's, but here's a video if you prefer it that way.

https://www.youtube.com/watch?v=yBUijLXYw5c