How to strengthen a steel angle frame against twisting/torsion?

[BrokenBiker]

I don’t think reading a book will help stop an angle iron frame like that from twisting . Outer frame as a minimum needs to be c section or box.

Bob

ive never found a situation where having more related knowledge has hindered my efforts...reading the book may not help with this frame as it looks naff from the start, but it cant hurt the attempt at re-making or re-designing

 

[ELL]

OK guys. I see people not liking the whole, trying to polish a T*** idea. The frame is too weak. So I will start from scratch with some box setion, or possibly thicker angle iron. Thanks for all your replies.

 

[pedrobedro]

Get some similar angle and make the outer frame into a box.

 

[zzr1200]

amazing, thanks

Name of book and Author + .pdf download.....sorted in most cases..

 

[dave h 2]

Best thing you can do is not buy cast offs from the guy who made his own hiab trailer as featured on here last year or so .

 

[BrokenBiker]

OK guys. I see people not liking the whole, trying to polish a T*** idea. The frame is too weak. So I will start from scratch with some box setion, or possibly thicker angle iron. Thanks for all your replies.

Doesnt necessarily need thicker angle, but being made correctly will be a massive improvement in itself, fully welded corners, fully welded cross braces etc...if it is then still too flexible you can, as suggested above, get some 16mm round bar and weld into the angle iron in strategic places...try twisting it, see where it twists, reinforce that area etc

 

[chrismac]

OK guys. I see people not liking the whole, trying to polish a T*** idea. The frame is too weak. So I will start from scratch with some box setion, or possibly thicker angle iron. Thanks for all your replies.

Box section is a great idea.

 

[Erie Fred]

I don’t think reading a book will help stop an angle iron frame like that from twisting . Outer frame as a minimum needs to be c section or box.

Bob

The book is great, has lot's of pictures too for the "reading compromised" members here.....

 

[ELL]

The book is great, has lot's of pictures too for the "reading compromised" members here.....

I'm more of a pictrures with text guy. I find in a lot of books that get technical, they miss the basics and don't tell you what a lot of terminology actually means. They expect you to walk when you're still at the crawling stage, if you know what I mean. Text and lots of pics is ideal.

 

[voipio]

Angle iron is great if the ends are anchored solid, and the forces from the load are applied parallel to the sides of the angle. What it isn't particularly good at is torsional stiffness, which is what the twisting moments on the door are applying. Box section, or tube, would be a far better construction material.

Replacing the steel angle cross members with box section would improve the stiffness of the overall construction, to some extent. It would be better, but not perfect.

 

[8ob]

The book is great, has lot's of pictures too for the "reading compromised" members here.....

Some people have engineering nous, some don’t. A book might help those that don’t instinctively know what’s right from wrong but from my experience most books tip toe around a subject. I read a book on suspension design once, it went into great detail of everything other than designing your own.

Bob

 

[knighty]

so... what are they for anyway?

 

[dave h 2]

I'm more of a pictrures with text guy. I find in a lot of books that get technical, they miss the basics and don't tell you what a lot of terminology actually means. They expect you to walk when you're still at the crawling stage, if you know what I mean. Text and lots of pics is ideal.

To be honest all you had to do is flex the, er 'door' whilst looking at the tacked ends. You would have seen the movement at the joint and maybe understood that an extra tack at the open end would stop that movement and give you a better idea of how stiff it would be fully welded.

 

[Erie Fred]

I would not Dish a book you have not cracked sir.

But that's just me.....

Some people have engineering nous, some don’t. A book might help those that don’t instinctively know what’s right from wrong but from my experience most books tip toe around a subject. I read a book on suspension design once, it went into great detail of everything other than designing your own.

Bob

 

[Erie Fred]

I'm more of a pictrures with text guy. I find in a lot of books that get technical, they miss the basics and don't tell you what a lot of terminology actually means. They expect you to walk when you're still at the crawling stage, if you know what I mean. Text and lots of pics is ideal.

Just get the ^%$#@! book.

 

[voipio]

Below is a relevant figure/table from the above mentioned book, showing the angles of twist for a given torsional loading on different sections. Look at the bottom two rows in the table. Sections "a" and "b" are the nearest to angle iron, shape-wise, with angle iron being somewhere in between these two, and these cross sections are poor at resisting torsional loading. Closed round tube and square section (also applies to rectangular), are by far the most resistant to twisting by torsional forces. The actual page in the book is page 2.10-3 [or choose page 101 in the pdf browser]:

 

[Erie Fred]

From the above mentioned book, the angles of twist for a given torsional loading on different sections. Closed round tube and square section (also applies to rectangular), are by far the most resistant to twisting by torsional forces. The actual page in the book is page 2.10-3 [or choose page 101 in the pdf browser]. Look at the bottom two rows in the table:

View attachment 499840

Some people will be corfused when they see numbers, might start taking off footwear...

The rest might find that table very helpful.


Or look at page 114.....

 

[chrismac]

Below is a relevant figure/table from the above mentioned book, showing the angles of twist for a given torsional loading on different sections. Look at the bottom two rows in the table. Sections "a" and "b" are the nearest to angle iron, shape-wise, with angle iron being somewhere in between these two, and these cross sections are poor at resisting torsional loading. Closed round tube and square section (also applies to rectangular), are by far the most resistant to twisting by torsional forces. The actual page in the book is page 2.10-3 [or choose page 101 in the pdf browser]:

View attachment 499840

I think I'll go back to being a welder..... point me in the direction something need stuck together..

 

[Erie Fred]

I think I'll go back to being a welder..... point me in the direction something need stuck together..

If you don't want to learn something new.... that's fine, the chart is not for beginners,
I can see where some might be turned off by it. That chart is what is in most books.

However you might just need a different way of learning, hence the book suggestion,
as it's not like anything else I have come across, look at the examples on page 114 where it put's that chart into practical use.

 

[BrokenBiker]

If you don't want to learn something new.... that's fine, the chart is not for beginners,
I can see where some might be turned off by it. That chart is what is in most books.

However you might just need a different way of learning, hence the book suggestion,
as it's not like anything else I have come across, look at the examples on page 114 where it put's that chart into practical use.

im only a few pages in but its already quite interesting, seeing the effects of undercut/fillet size with numbers linked to each test gives me a better understanding of just how much it actually does effect the part not just 'undercut is bad, it will all fail'