Contacts, please explain

[Anonymous]

Hi,

Can somebody explain me what the different CONTACTS are used for in Stress Analysis

Bonded

Sliding / No seperation

etc..

I can't find them in de help of Inventor.

Or a link to a clear tutorial for using Contactsets in Stress Analysis

Thanks

[JDMather]

http://store.autodesk.com/DRHM/store?Action=DisplayProductDetailsPage&SiteID=adsk&Locale=en_US&Env=B...

http://www.vdssolutions.co.uk/

[Anonymous]

Thanks JDMather,

I have ordered the books, to bad Inventor hasn't got a detailed tutorial about the stress module.

I think it will take a while before the books arrive, so meanwhile, maybe you can help me with this puzzle.

I have a panel that rotates with a simple constructed hinge.  Square tube around round bar.

The round bar has a diameter of 40 mm, the inside of the square tube is 42 mm.

I need to calculate the stress on the panel, round bar and square tube when the panel is pushed open with a hydraulic cilinder.

I don't know what contact i need to select in the Stress Analysis so that the square tube can rotate around the round bar.

can you or somebody else help me?

See attached file

[henderh]

Hi dodrain,

  It may be better to start the simulation in Dynamic Simulation to find the unknown force that the hydraulic actuator needs to provide in order to open the panel to the desired angle.   You can use the Unknown Force command in DS to accomplish this. Once you have the computed force at the desired angle, you can use this as the input force in Stress Analysis.

  In SA, I noticed there is a minimum 1mm gap between the cylinder and square tube.  Automatic contacts will not be created by default, since the default contact tolerance is set to 0.1mm.  You can either increase the default contact tolerance to account for this, or create manual contacts.

  The way that the cylinder is smaller than the ID of the square tube, there will be at most two simultaneous contacts between them when the load from the actuator is applied.  You will probably need to re-constrain the assembly to account for this.  If the hinge is well-greased I would use a sliding / no separation type contact as opposed to bonded, since bonded would treat them as welded, or glued together.  The sliding will allow some movement and the no separation will block any penetration.

  What I'm wondering is which (initially vertical) inside face of the square tube will contact the cylindrical pin once the panel is at an angle.  I can't tell for sure from the image, but I would imagine that it would depend on whether the pin for the actuator is located above or below the center of gravity of the door.

Hope this helps...

Thanks, -Hugh

[Anonymous]

Thanks for reply, if i have any results i will let you know.  I wonder why there isn't much tutorials and examples delivered with Inventor concerning dynamic simulation and stress analysis.

[henderh]

I'm not sure if you're aware of this already, but in addition to the online help and tutorials that are shipped with Inventor, we also offer skill builders (for free) that you can download http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=10899589&linkID=9242016 <= Contacts, Convergence and Optimization for Stress Analysis

There is also a white paper for Stress Analysis (Numerical Result Validation) available here: http://usa.autodesk.com/adsk/servlet/pc/index?siteID=123112&id=14003843

Thanks, -Hugh

[JDMather]

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@Anonymous wrote:

I wonder why there isn't much tutorials and examples delivered with Inventor concerning dynamic simulation and stress analysis.

---

Near as I can tell there aren't very many people using it. Yet!  Part of the problem is faculty don't know how to use it and they need 2 semesters worth of documentation to add to the curriculum.  The documentation should include enough labs to do a lecture on say Tues and the students do a lab on Thur for a period of 30 weeks or so.  Plus extras for the professor to pick and choose from.  There is not nearly this much documentation.  But still, something revolutionary needs to be done to educate faculty. The company that realizes this first and does it first will own the Digital Prototyping future.

In the past I have recommended that Autodesk hold something like http://singularityu.org/ focused only on Inventor for competative award to faculty in an attractive location.  This would then ripple out to the design community.  There is an enormous amount of functionality built within Inventor that never even gets touched.  Stuff in the Design Accelerators, FEA, Dynamic Simulation, Tooling......  ....some bright people could get together for a few weeks and develope some really impressive tutorials/examples/case studies.....

[Anonymous]

Dear JDMather,

I love the way Rob Cohee explain things in small broadcasts. The tutorial of Inventor should also have recorded broadcast, especially for the more complex items as you mentioned FEA,  Dynamics etc...

For my example i have put some Jacks on the panel to push it open, so i can discover what force i need in the hydraulic jacks.

But when i run Dynamic Simulation the panel keeps going up and down.  In real life a jack has a stroke length you can define.  The jacks in the joint section hasn't

Now i'm searching for the method how to discover the jacks don't destruct my panel, hinge, frame when opening en closing the panel.  I really need this for my project.

[JDMather]

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@Anonymous wrote:

  The jacks in the joint section hasn't

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Input Grapher.

I am not aware of a motion that cannot be done once you gain some experience.  I have been working with this a couple of years now and I'm just beginning to feel a little bit comfortable.  Enough to know that I've only scratched the surface of what can be done.  Truelly amazing capability hidden in DS.

[Anonymous]

I ordered book from Autodesk store.   Shipment with UPS. Payed in advance.

UPS delivers book on my door and charges 20 euro extra for Taxes. Why doesn't Autodesk charge taxes from start when you order books

143 $ for the book inclusive shipment from Amerika + 20 euro taxes, i hope the book is good  🙂

[JDMather]

I think you should have downloaded the electronic version.

The other (Wasim Younis) book is better.