pro/mechanica pt 2

Hello again
I have worked out how do asimple beam, and am satisfied that the
results are correct. However, when i try and do an analysis of a
sketched eam, even a square or round shape, i get no bending. Is there
something i am missing. I am simply swapping the standard beam section
in the analysis for one which when sketched has exactly thesame shape
as the standard one

cheers
Craig

 

A "sketched beam"? A "square or round shape"? Let's say you wanted to do a study
of a twelve inch I beam. What would your beam sketch look like? It would be a
simple, straight line. When you got the sketch constrained and loaded, you'd click
the 'New Beam' icon which would give you the opportunity to set a meterial and
define the shape/size of the beam end profile. Lots of standard extruded shapes
are available, including round, hollow round (pipe), hex pipe, eliptical pipe,
i-beam and c-channel, square, etc. It really depends on what you've picked as
defining the beam: a surface? curves? When you pick surface, this is thickened so
you have a plate the shape of your sketch.

If you just made an oblong, it was probably expecting to select a surface that
filled the inside of the sketch. It would have to assume a THICKNESS value and
probably gave you something that was unbendable. Typically, with sketched beam
profiles, the sketched lines are each turned into a beam section by using it as a
path for "sweeping" the beam profile you define (c-channel, i-beam, square, etc).
That's quite a different structure from filling the inside of a sketch with metal.
And reacts differently.

 

I'm using a curve as my beam length, and trying to use a non standard
section as the beam profile. As I am still learning, I am doing "baby
steps", so that I can be confident of getting results that are
accurate. So I just sketched a profile of a square, to ensure I am
using the sketched profile correctly. However, when i am selecting the
sketched profile of a square , i get no bending stress, leading me to
think that i am not entering something incorrectly in my analysis, or
on my beam setup.

cheers
Craig

 

I read your post, Craig. Are you, in any way, responding to my suggestions? Did
you do one single thing I suggested? I'm sorry, I'm kinda lost! I don't see
anything in response. Please, state your procedure for working with this beam
idealization. Button push by button push, if you will, as if we were a really
intellingent PTC Pro/HELP line. In the words of the immortal Jerry McGuire " Help
us help you! "

 

I thought i was responding to your post. Anyway, I'll describe what i
did

step 1 . create sketched curve

--> applications mechanica
--> insert --> beam

Beam definition menu
-->
references: edge/curve, select sketched curve
section: new-->
type--> sketched solid

create a sketch of a square, centred on the coordinate system, 47 mm
--> ok
--> ok

constraints
fix the two ends of the curve, except for a Rx

Load
create a point halfway along the curve, and place a load on it

Analysis
--> mechanica/analyses studies
file -->new static --> ok
run -->start
summary

The only thing i have done differently from an analyses that worked,
was to change the standard section into a sketched section.

Thanks for your help

Cheers
Craig