How to join structural members? Help please.

[Roxana]

Hello:

I am new with inventor and would appreciate if you could help me go the right direction with a structure I am trying to build with extrusions of Cylindrical and Square cross section.

I am having a hard time making sure that when I join the members they do not just intersect one another...

I will need to do a stress analysis on this structure later, so I want to make sure my geometry will allow for that. But simply, how do I join, let's say, a square section member perpendicularly onto a cylindrical section member? I mean, without either intersecting a member into the other or leaving a gap of space between their surfaces? The joint surfaces will later be spot welded and would of course need to mate. So for instance, the end of a square extrusion would have to end up with a radious instead of remaining flat ended in order for it to mate onto the curved radial surface length of the cylindrical extrusion.

I am hoping I am making myself clear. Sorry for the rambling about this...

Your help will be greatly appreciated.

Thanks very much.

[jong]

Done a lot of this.
There are 2 approaches.
1) build the frame as a lot of individual parts (which is what I suspect you are doing) you then need to model the ends of the members ie bevels on square tubes or a round cut where it meets a round tube.
A good whiz is to model the parts in the assembly and use faces or planes to extrude the parts too.
2) a quick and dirty solution for say a box section frame is to start with a cube cut out the spaces to leave the members, add fillets then shell it out so it all becomes hollow. This is simple but you won't get cutting lists and individual drawings of the bits but heck who need a detail drawing of a tube cut to length.
3) If you want to add weld details ( depends on your FEA package) then either start with a weldment assy or switch it on later. As a tip ad the welds as late as possible big design changes can cause some of the welds to get confused when edges dissapear this has probably got better in the newer releases.
Note: if you build as an assy then parts lists etc get done but it is well worth spending time planning out what file names to use for all the members and the assy before you start
Hence if you are say doing a car space frame you could build each bulkhead frame as a seperate part then position them in space in an assy and extrude all the extra tubes to meet the existing parts
JonG
Enjoy.

[Roxana]

Hi, I am trying to follow your suggestions. I very much appreciate your reply. I feel like a real beginner and wonder if there are any online tutorials or better video tutorials that you could direct me to. I cannot find anything specific and friendly enough in the HELP sessions...

Thanks.

[Roxana]

Hi, would you be able to explain to me in more details what you are suggesting with you comment:

"you then need to model the ends of the members ie bevels on square tubes or a round cut where it meets a round tube.
A good whiz is to model the parts in the assembly and use faces or planes to extrude the parts too."

Perhaps you could point out a link to a tutorial or a help session? I am sorry, I am just having a hard time following your suggestion and am basically having a hard time understanding how I can easily join, let's say, a square channel perpendicularly onto a cylindrical pipe for instance. I am building a structure with several members of different cross section, and would like to be able to join the members at different angles and do this relatively expediently.

Thank you very much for any help.

[jong]

attached are 2 files
1 a box frame done as 1 part
2) a piece of angle with adjustable bevels ( put this in the templates folder. start mew parts from here. then you can soon build up lots of cut angle to assemble into a frame.)

Note both parts have the red dot and eon of part note inthe broser pulled up to the top of the tree. This makes the files smaller to e-mail as you drag it down the model will rebuild.
doing this will allow you to see how they have been done.

Also look at Parameters in the Part features menu box or
TOOLS>Parameters
Have compressed both files into a zip file jongardam.zip
hope this helps

[Roxana]

Thank you. I will try that.