Help with beam design

Dang man, nobody replied even to your second request! I have pretty much the same question. I will let you know if I figure it out. dean s

Go to Mcmaster-carr's website and search for gantry crane,steel. Up pops a page with lot's of specs and dimensions! You should be able to build one from those! If in boubt, 'sizeup' to the next bigger crane, if it'll fit into your shop.

Heck they want over 2000 for the crane.....

hth jay

bill, is this program available on the net? thanks dean s

Hey Bill,

What is the program? Is it available on-line?

What size does it suggest (in one of the standard I-beams, or standard H-beam) for a 10 foot span, fixed both ends, 6000 pound live load at one point in the centre? Safety factor of?

You tell us that, and I'll start to warn him about safety problems if he's making it a moveable load or moveable gantry!

Take care.

Brian Laws>Ive got a program that will do beam designs, but it will only do verticle

Take a look at Grainger's online catalog as well. I looked around to see what was comercially available to assist in the design of my gantry. I did the calculations as well. Ultimately I wound up with a beam that was way overkill for my application, 1 ton capacity, but priced right. Take a look in the dropbox and look for Gantry_Crane to see what I built.

Since you don't want it to be on casters, I would suggest simple end columns that sit on the floor with an A-Frame to stabilized it. This will be the strongest and easiest way to construct the end frames.

My design enables the ends to swivel which is really handy for manuevering into tight places. Since you don't have this need, drop the complexity and keep it dirt simple. Remember that beam section size and span both contribute to the load carrying capacity.

Lifting heavy objects can be dangrous work. Building equipment to lift heavy objects when not properly done can result in very hazardous conditions. Something you may want to research a bit more than just take anyone's word for on the web.

Many years ago a load of 3 tons had to be lifted. The lifting boom was anchored at the bottom and leaning out about 30 degrees from the vertical, the top of the boom was connected with an horizontal steel cable to the building structure. The worker called the engineering department and asked what the maximum load capacity was of boom part No. xyz. The engineer called back and said: That boom will fail in buckling at approximately a load of about 5 tons. The workers decided to go ahead, in their opinion having enough of a safety margin. The boom collapsed and one guy got killed. The problem was that the load was hoisted by a winch with the cable going thru a pulley at the top of the boom and down from the pulley to the load. The two cable forces of each more than 3 tons (its more than 3 tons because the 3 ton load has to be accelerated to hoisting speed) went thru that pulley into the top of the boom, loading the boom with more than 6 tons. In this case the engineer was to blame for providing an answer without having all the facts. Frank, I suggest that you make sketches of what you want to build, complete with material specs and approx. dimensions. Also details of how you want to connect the sections together. Then present that to an engineer or qualified contractor or your local building inspector. HTH

gradstdnt wrote: (Snip)

(Snip)

Wow! Very nice!

What program did you use to do the FEA? Is it an Autocad plugin?

--Winston

A local building inspector will not have the skills to do a calculation on a lifting device, much less a simple beam calc. Please don't go to a building inspector for this. If you really want to know, run it by an engineer.

JTMcC.

HTH

The program is not an Autocad plugin. It is a Pro-E type of software program that is both CAD and analysis tool that links the two together. I was able to do the design and analysis with one package. As one can imagine, such a bit of software takes a bit of time and effort to learn. It did yield value added as my original assumptions of what I though I needed were better refined to allow for a lighter structure that is easier to move around.

In a past life I spent a lot of time using CAD tools so the design and analysis using the computer was second nature. If you don't have any formal training using such tools, any attempt to work them occasionally can be an excercise in extreme frustration. Kind of like trying to pick up a second language by only speaking it a couple of hours on the weekend.

I agree with that in general, but I'm one of those who use CAD and FEA on an irregular basis, and I've found that there is one lightweight FEA program that I can drop and pick up from time to time without much trouble. It's CADRE Lite

There's a trial version that is fully functional (or the old version was; I own it now, and I haven't tried the trial for a couple of years).

It won't do a lot of things that we expect of fancier FEA packages, but it's good for simple structures. I've used it to analyze a couple of spaceframe designs I'd already created in CAD (well, in Rhino, actually). It was very straightforward and fairly simple.

However -- and this is a big however -- no simple FEA program is going to be simple if you don't know basic engineering statics pretty well, including things like elastic modulus and radius of gyration.

Ed Huntress

Hey Guys,

A friend has written asking if I can help him out with a Java appelet. I cannot, but his question sounds pretty simple to someone who works with Java, so I'm wondering if anyone here might know. Replies to would be fine.

Question: "I've picked up a sail-boat race scoring program with source code and all, but would like to alter the printed output as it has a gray background with black data. I'd like to change it so that it prints on white paper without using up all my ink supply on coloring the background in gray. I've scanned the source code but haven't been able to find where its creating the gray background. The program utilizes the browser's print function to list the results. Again, any help would be greatly appreciated."

Any help greatly appreciated.

Brian Lawson, Bothwell, Ontario.

Hi James, I suspect for the backgrond it sounds like a frame and you will find a line that looks like

setBackground(Color.gray);

change to the basic colors of course, also, if you want something less boring you can set the color with a RGB number, I forget the limits at the moment. Though in your case it sounds like you want setBackground(Color.white);

thanks for asking, hope this helps, made me get out a reference book and found an interesting program to generate fractals.

mark

Brian Laws> Hey Guys,

Alternatively, if they are using IE, go into the advanced options, and turn off "print background colors and images".

HTH, --Glenn Lyford

Hey again Guys,

Thanks for the help. Great group. Below is what my friend sent me this morning.

Brian. XXXXXXXXXXXXXXXXX Hi Brian, Well, thanks to you and your friends for pushing me in the right direction I was able to correct my problem. I started out by trying to find "setBackground(Color.gray)" in the program code - no luck there. Next I looked in the JavaScore file folder and found the print file that was created. I then printed the file directly to the printer and the output had a white back ground so I came to the conclusion that somewhere in the browser was where the background was set to gray. I found it and over wrote the color with white only when processing this program and everything is now working just fine. Attached is a copy of the race results - page 1.

Thanks again, Al