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Designing an automotive passenger airbag.

Edward_O_ThorpEdward_O_Thorp Member Posts: 5
Hello Everyone,

Myself and a few friends are working on developing a new airbag (AB) for automotive passengers. It will be a double bag system, that is, an outer and a separately inflatable inner bag. How would I start to model an AB with the outer and inner bag? Both of them would inflate with canisters. I am new to CAD/CAE. TIA.


  • billy2billy2 Member, OS Professional, Mentor, Developers, User Group Leader Posts: 1,585 PRO
    I'd do a single surface. I wouldn't worry about the thickness of the bag. If the inner and outer are just slight offsets; I'd show one surface for both. 

    The thickness will probably kill it. I wouldn't show thickness.

  • Edward_O_ThorpEdward_O_Thorp Member Posts: 5
    Thank you.

    According to sales and tech support I can do the modeling of the whole system with the inner and outer bags.

    What do you mean by single surface? TIA.
  • tim_hess427tim_hess427 Member Posts: 568 PRO
    Hi @jerome_papa

    Welcome to the forums. 

    I think from your original description, its a little difficult to understand exactly what you're trying to model and what you want to do with the model. I believe the point that billy2 was trying to make is that modeling the thickness of the bag fabric probably wouldn't add much value to your model but would make it harder to model. So, he was recommending the use of 3D surface modeling as opposed to modeling a 3D solid material. In the case of the surface model, you could define the overall shape of the bags. 

    The learning center has some useful videos that may help you understand surface modeling: 

    One issue that you may find, is that Onshape doesn't have a good way to model soft materials like fabric. So, you can model the shape of the inflated bag, but Onshape doesn't have any tools to show you what the flat shape of the fabric would be for cutting and manufacturing. However, if you can provide any more details on the goal of your model and how it will be used, I'm sure people here could help you find ways to do what you need. 
  • Edward_O_ThorpEdward_O_Thorp Member Posts: 5
    Thanks Tim. Does the pro-version have different materials which can be used for modeling the AB?
  • tim_hess427tim_hess427 Member Posts: 568 PRO
    The pro version of Onshape has all of the same modeling tools as standard. 

    I know you can create custom materials with paid versions of onshape (I'm not sure if you can in the free version), but is only a "property" that's assigned to the model and doesn't impact the geometry. 
  • john_mcclaryjohn_mcclary Member, Developers Posts: 3,302 PRO
    I believe the ability to create a custom material list is linked to a company. Which requires a Pro account or greater.
  • MBartlett21MBartlett21 Member, OS Professional, Developers Posts: 1,953 EDU
    I think free users can create material libraries. I know I certainly can.
    MB - I make FeatureScripts: View FeatureScripts
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