STRESS ANALYSIS PROBLEMS

[Anonymous]

I need help figuring out where I should indicate my force loads, contact sets or anything else if necessary. Having a huge problem with this and very confused and annoyed. If anyone can help, please HELP! would be GREATLY appreciated.

I attached a picture of the product, hopefully someone can indicate where I can place different loads or if anything applicable. Don't really know what else to do. This is my last hope.

[TheCADWhisperer]

Has  your instructor covered FEA analysis (especially, the limitations of)?

[TheCADWhisperer]

Oops, wrong thread.

[johnsonshiue]

Hi David,

Is this a school project? If yes, have you talked to your teacher or class assistant? If I were you, I would talk to them first. Regarding simulation tips, I would start with something simple. For this case, you don't need to start with all 8 branches. You could isolate the model so there is only one branch plus the main support. For adding load and constraint. You want to make sure the main support is fixed so it does not move around. The load on the cloth support should be 1/8 of actual requirement. Once you can successfully simulate branch, it should be a scalable process to expand to all branches.

Good luck!

Many thanks!

[Anonymous]

i don't need to do a dynamic simulation. Just a stress analysis where a specific load would be on the canes handle, and maybe a load from the umbrella where it connects to the cane. However, I just need a little help with positioning the force load and other possible forces and constraints.

[JDMather]

Analyze only the handle by itself (the rest is too complex and certain aspects are beyond the capability of Inventor FEA.

Split Face the area of the handle where one would normally grip the handle.

Split Face the hole a nominal distance down into the handle.

Add a Bearing Load perpendicular to the axis of the hole in the handle.

Experiment with varying load up to SF=1.

Attach your file here if you have trouble figuring it out.

[Anonymous]

here is the attached file. Having a bit difficulty with this. Thank you.

[TheCADWhisperer]

I tried to simplify the problem to something manageable, but Inventor had trouble with the mesh.

I think that if I had time - the next thing I would do is remove the Top.ipt.

Inventor is not indicating Thin Bodies, but given the aspect ratio of the Central Rod, I might override and set Midsurface offset.

[Anonymous]

I planned on doing the stress analysis on the canes handle not the umbrella handle. If you can see in what I posted earlier, I took a screenshot of the design and just need indication where to place features and load forces and contact sets.

[TheCADWhisperer]

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@Anonymous wrote:

I planned on doing the stress analysis on the canes handle .....

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I do not see a file with that name?

It might have been less confusing to attach only 1 *.ipt file.

In the Cane(MM).ipt file there is a hole that is incorrect tap drill size for an M8 thread?

Several unconstrained sketches missing dimensions?

Some very sharp edges?

Wood is not an isotropic material.

Can  you ask your instructor to join this discussion?

[Anonymous]

Okay I see what you mean. Unfortunately, my instructor would not be able to join the thread. My knowledge on Inventor program isn't above average. However, I tried to do the best I can based on my abilities and prior knowledge. I will change the thread on the hole of the cane as well. I will attach the cane ipt file since that would be the only part that will undergo stress analysis.

I have a question as well. I tried to do the stress analysis myself on the canes handle, I inserted about 178 N force load to compensate the quarter weight an average elderly person may be exerting on the cane. And so with the force load placed on the hump and the edge of the cane handle, should I place a constraint anywhere? If so, where? 

[swalton]

I like to make a Free Body Diagram of my parts and assemblies when I start a new FEA study.  The process makes me think about how to load and constrain the components.  If my hand calculation of the reaction loads does not match the FEA results at the constraints, I've made an error somewhere and I can't trust the FEA until I find the problem.

Anyway, think about both where to apply the load and how the component is restrained in space to resist the load.  Those restraints in the real world become your constraints in the FEA.

Also, if you can find a copy of "ISO 24415-1 Tips for assistive products for walking —Requirements and test methods" and "ISO 11334-1 Assistive products for walking manipulated by one arm — Requirements and test methods —" and any related standards, you will find some real-world test requirements for these types of products.  I did not have time to look for a standard for the exact type of cane you are modeling, but these standards might give you some additional load cases to use in your FEA.