A36 Plate Steel Thicknes For 35,000 Winch

[bbpfab]

Hi all I am new here and run Autodesk Inventor 2012 Pro. I am designing a mount plate for behind the cab of a semi. The winch will be mounted so that 8, 7/8-grade 8 bolts will be in shear. The mount plate is a36 steel that is currently 1/2-inch thick with a flatness of no more then .02-inch. I just would like to know if the 1/2 plate thickness is enough or should I bump it up to 3/4-inch plate to add a bit more beef? see attached basic drawing.


Thanks,
Aaron J. Potts "Pottsy"
Metal Artist/Mechanical Designer

Built By Pottsy LLC
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[drawoh]

bbpfab,

I observe that no one is responding to your question.

You are asking a question requiring significant engineering. The consequences of any mistakes are potentially lethal. You don't want this thing failing out on the highway, and/or with someone standing underneath it.

You need to contract this out to an engineer.

The qualified people are not going to answer your question "yes" or "no". There is way more to it than that.

--
JHG

 

[racookpe1978]

Per the above comment ... "Add a bit more beef"?

In "my defense" please explain why you are concerned enough about strength, ultimate pullout/pulloff of the trailer, fatigue failure, etc to feel like you want to "add more beef" to your design?

Something is bothering you enough that you are not sure of your (already calculated) results for the current plate.

But - you're in a business selling to transportation and a very - repeat! very competitive trucking industry facing fewer loads and higher fuel costs today! Weight (unneeded weight actually) is expensive to buy, build and fabricate, and to "ship" both to your customer and behind his truck. A heavier plate - if the weight is indeed unneeded - gives you a more expensive product due to more steel costs, more welding thickness, more cutting time, etc. (all = fewer sales), more expensive shipping (fewer sales) and a more expensive product to use every day (more fuel costs to your buyer = fewer sales.)

Justify why you feel you need more strength. To yourself, if not to your boss. There are times when he'd (she'd) prefer to get the ability to decide between two alternatives - IF !!! - you have done both calculations.

Can you use a higher strength alloy to save weight and give you an advertising "edge" over your competitors?

 

[bbpfab]

I hear both of you. The winch is a 30,000-lb unit that will be foot mounted. The mounting specs for the winch from the manufacture (Domestic U.S. Made High End Winch MFG>) state 1/2 plate as a min. I feel completely comfortable with my design, but owner of the company I design for would like to increase the plate to 3/4. I was just looking to see what everyone here had to say.

Thanks All...

 

[Jboggs]

I say make the owner happy. Steel is cheap.

 

[MiketheEngineer]

Without running all the numbers - 3/4'' is about 50% stronger than 1/2'' and he is your boss. So what are you arguing about??

 

[dhengr]

Your feeling “completely comfortable with my design” does not make it good or adequate design from the structural standpoint. So far, all you seem to have is a drawing which might have matching bolt holes, and a hole cut for the lower parts of the winch. What you have shown is drafting, not design or engineering. That winch applies a 30kip load, 16" +/- above your base plate causing both shear and tension in some bolts, and significant bending in the base plate. That is what truck owner is worried about, and at this point you have not shown that this has even been considered. And, you have not provided any info. which would allow any meaningful discussion beyond the above.