Inventor Stress Analysis

[Sevem]

Hi guys, i just started to use IV2011 and i have a few questions regarding the forces in Stress Analysis.
I have a bar fixed between 2 walls and someone does pullups.
Let's suppose that that person has 90 Kilo's (that means 900 N, right?).
How do i put the two forces that represents the guys 2 hands.
And when i put a force that force it's applied in a point or on the entire surface?
I don't have to do the pullups bar,
but this example will make me understand better and how to dimension the parameters.
I've attached the assembly if someone has the time to show me how to do it.
Another question, can i draw and use in stress analysis a flexible cable (Bowden cable)?
Sorry if i asked stupid questions, but i have no experience with stress analysis.
Thanks.

 

[btrueblood]

You can apply forces in the 2010 Inventor Pro package, at lines or surfaces. So, your model would have to have a feature, e.g. a slight change in diameter in the area of the hand's grips, to select for applying the force boundary conditions.

It's unlikely that inventor will model a braided cable correctly, even if you modelled the individual twisted strands. I haven't tried, so can't tell you yes or know, but I'd be very surprised. Any significant length of braided cable would likely cause the modeller to choke, too many little boundary conditions where the strands contact each other for the computer to keep track of. It might model a single wire strand reasonably well, but only for elastic deflections, it won't model any plastic deformations.

 

[btrueblood]

"Sorry if i asked stupid questions, but i have no experience with stress analysis."

Would suggest getting educated in the subject, either take an elementary class or two at university, or get a book or two and read up. Especially if you intend to use the results of the inventor modeller - it's a useful tool, but you have to know its limitations.

 

[mcgyvr]

You can use the vector xyz dimensions to place the force in the area you want.. Or use split or a small extrusion to create a small face where you want your loads applied.

and to add to what btrueblood said.. a FEA package in the hands of someone who is inexperienced will only lead to incorrect results. Many people think "oh wow this program will take all the thinking out of analysis"..That is simply incorrect. A FEA analysis is only as good as the input fed to it by the operator.