How to check whether a given structural support or frame can support a given machine 4

[mechanicaljw]

Dear all,

I wanted to find out if structurally, there is a rule for finding out if a given support or frame can support a given machine?

We have a current frame that supports a single machine but we need to connect or build an additional machine on top of this first machine and to support it with the same frame used for the single machine. How do i check if this is possible?

Thanks!
James

 

[hokie66]

Thanks, BA. I apologize, thaidavid40. There was nothing personal, but it is commonplace on the site for members from different countries to poke a bit of fun. I suppose the most common is for many of us to take exception to things like the naming of the "International" Building Code. By the way, I am US born and bred, living in Australia, so I have some standing to be sarcastic about North American things.

 

[thaidavid40]

@hokie66
Thank you for your apology, and I can see now that your original statement was an attempt to poke fun at me. Surprisingly (to some), I actually do have a good sense of humor - much of it self-deprecating. In a terse, written format like this website, our attempts at humor or sarcasm sometimes do not read quite right on the other end. That is one reason that I try not to use such in a setting like this, but rather try to focus on the original poster's question, and not on the respondents specifically. I am American also, but I lived and worked in Thailand for over ten years (eventually teaching engineering college in Thai), and I have worked on projects around the world (from that setting, and later, for the US military). I have seen enough in that time that I understood that there are resources available for professional design no matter where in the world you are located. My second reply was simply an exhortation to the original poster to seek qualified help on an important safety subject. Some reader "starred" it, so they likely have had a similar experience too.
And I apologize for failing to catch the intent of your post. I didn't mean to offend you either.
Thanks,
Dave

Thaidavid

 

[mechanicaljw]

Hi Kingnero,

I forgot to add that in one case, the beams are not touching the floor. In that case, the beams are connected to 4 rubber mountings of height 35mm. In this case i guess you will not add any load at the bottom of the beams in the modeling?

I agree that with the four bars, the structure is not stable. I remember for stability, S=2k-3 must be satisfied, with S the number of bars and k the number of nodes. For k=4, we get S=5 and so an extra bar would be needed as you suggested.

Thanks for your support.

Jimmy

 

[BAretired]

If the four rubber mountings are located directly below the four applied point loads, the channel members have no bending moment at all, but if all nodes are hinged, the structure is unstable and will collapse.

BA

 

[zcp]

This might get you started:

http://ocw.mit.edu/courses/mechanical-engineering/

Good luck! Suggest hiring out the review and then learning from it for the next one.

ZCP

http://www.phoenix-engineer.com

 

[lukin1977]

Steel is cheap so use plenty of it

 

[BAretired]

Steel may be cheap, but you are not going to get the most out of it if you notch the top flange as you are showing in your sketch.

BA

 

[mechanicaljw]

@BA: What do you recommend we do if notching is not going to work?

Thanks!

Jimmy

 

[kingnero]

not notching, as it seriously impairs the geometrical properties of the U-shape with respect to its resistance to bending.

 

[mechanicaljw]

@BA: I forgot to add that the mounting points at the bottom with rubber are not directly located under the notched points at the top. It looks so from the sketch but that is not the case.

Thanks!

Jimmy

 

[BAretired]

@BA: What do you recommend we do if notching is not going to work?

1. Tell the boss he can't add another machine on top of the existing without modifying the existing frame.
2. Modify the existing frame as required to accommodate additional machine on top of existing.

BA