Inventor Multibody Part

[Anonymous]

Hi there,

can somebody please answer me the following question:

Is Autodesk Nastran In-Cad able to handle a multi-body part like an assembly? I mean is it possible to assign different materials to the single bodies of the multi-body part or can this only be done if a real assembly is loaded?

I am looking forward to receive your feedback on that request.

Regards

Matthias

[AndrewSears]

Hi Matthias,

Right now we do not recognize multi-solid bodies (MSB) part files as assemblies in the you are hoping.  This is something we are investigating.  We do recognize solid bodies as having the ability to move apart so you can at least get close.  Contacts will need to be defined.  The only real difference you will find are that the physical definitions will be restricted to one solid, line and shell element.  So, you can still have a mixed model with one material definition per each of the three available physical definition types.  

Below is a screen shot showing a MSB part with a line element and shell element included with the two solid bodies defined by solid elements.

Hope that helps and don't forget to use continuous meshing with shell elements and define mesh refinement for the line and shell element contact points/edges.

Thanks and keep the comments coming!

Andy 

[saainsworth]

This is definitely a needed capability.  Numerous small weldments that require analysis are modeled as multi body parts.  In some cases differing materials are used.  In some cases bodies are added to mimic mating parts in order to produce more realistic constraints.  In these cases the mating bodies not viewed as part of the results and are turned off.  Having to do this as an assembly is painful.

[Anonymous]

This is a very basic requirement for FEA. It wont be successful without this feature. For example, for a simple thermal analysis, where a part is covered with insulation, I can not assign different material properties for each part. In my opinion, Autodesk should look into this on priority.

[Roelof.Feijen]

Hi @Anonymous ,

I do not agree with you that this would be a basic requirement for FEA and that it wont be successful without this.

Please make yourself familiar with the multi-body workflow in Inventor. In a multi-body part go to the Ribbon's Manage tab > Layout panel > Make Components. It's very easy to create an assembly from a multi-body part if you need to apply more than one material property.

I agree with you that it would be nice to have the possibility to apply different materials to different bodies in a multi-body part. That is why I voted for this and this idea on the IdeaStation.

[Anonymous]

Thank you for the response. May be I did not explain it enough. I am very much aware that we can have multibody parts in Inventor. However when it comes to FEA, in most of the cases, which involve stress or thermal analysis of  a component having multiple bodies, it is very much required to assign different material properties for each body or part. I understand it is not possible in Inventor Nastran. Please correct me if I am wrong, and let me know how to do it. That's why I said it is a basic requirement for FEA of most of the industrial problems.

Please note that my comments are specifically for FEA capabilities and not in general for Inventor capabilities. In general, I find Inventor as an excellent tool for 3D modelling and automation. Please excuse me in case my understanding is incorrect.

BR

Kunal

[Roelof.Feijen]

I do understand your situation very well and I agree with you also. I also would like Autodesk to change this for the solid elements/idealizations (Shells and Line elements can have different properties). That's why I voted on those idea's that I mentioned in my previous post. You also want Autodesk to change this, not?  So, vote for those idea's.

[belinda94306]

I've looked at a few threads in the forum related to lack of control for complex mix mode meshing and lack of overall meshing / numbering / element creation control.  I'm not really satisfied with some of the responses

Having used various different versions of Nastran including MSC, NX, and NEI in the past it is possible to create models with 100,000 elements and nodes containing mixed mode linear and parabolic solid elements, linear shell elements, linear shear elements, beams, bars, rigid elements, spring damper elements, etc., with 100's of different idealizations, and materials, from a single body, a single part, or from multiple input files that were either solids, surfaces, curves, iges files, step files, etc. into one single model only needing contact elements when contact analysis was needed.  Cosmos, Ansys, Algor, and Patran, and Femap all have or had this capability.

The lack of control in the meshing controls to create orderly mapped meshes in zones is extremely frustrating   The lack of the ability to create nodes and elements via extruding, revolving sweeping, or to manually create elements node by node, the lack of the ability to control the element and node numbering schemes is also frustrating. 

Having used NASTRAN for 30 years, I know it is not a limitation on the Nastran side of things.   Even if it is a separate module, Autodesk needs to get serious about providing a better FEM pre and post processor module with the capability of doing more complex mixed element type models with more user control features.

fyi, I've purchased and used AutoCAD, Mechanical Desktop, and Inventor products for more than 20 years.  In spite of my frustration, I will continue to support the Autodesk line of products.