Stress Analysis

[J.Kahn]

If someone was to design a steel tube fuselage or a modification to a
steel tube fuselage, does anybody know of a relatively inexpensive and
painless way to get a stress analysis done, or software to do it?

John

[[email protected]]

On Jan 14, 9:31 am, "J.Kahn" > wrote:
> does anybody know of a relatively inexpensive and
> painless way to get a stress analysis done,

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'Stress Analysis Made Painless' by Raoul J. Hoffman.

Mr. Hoffman was an aeronautical engineer who crunched the numbers for
Matty Laird. His series of illustrated articles on stress analysis
appeared in flying magazines during the 1930's. They began with
'Properties of Airplane Materials' and included 'Elementary Graphical
Diagrams,' 'Graphical Resolution of Forces and Loads' and more than a
dozen other extremely valuable articles written for the novice
engineer.

Back when the EAA cared about more than air shows the Hoffman articles
were compiled in a single manual 'Engineering for the Amateur Aircraft
Builder' and offered to members for two dollars.

There are also a number of texts intended for the first-year
engineering student such as 'Fundamentals of Aircraft Structural
Analysis' by Frederick K. Teichmann.

During the 1930's most high schools in America offered courses dealing
with aviation. These were supported by a number of texts that usually
included stress analysis at the practical level, showing not only how
to do the various calculations but how to set-up practical experiments
for testing ribs, beams, struts and so forth.

Aviation trade-schools run by Boeing (Oakland), Northrup, Spartan and
others often published their own manuals, all of which touched upon
stress analysis although their main emphasis was on maintenance &
repair, rather than design.

This material is still out there although it's getting harder to
find. The physics & math hasn't changed -- the equations remain the
same -- and are just as applicable to today's home-builders as they
were to the yesterday's aircraft manufacturers. This subject also
provides a neat lesson in America's decline, in that you can see the
same basic-level material once offered in our public high-schools now
treated as a college-level subject for which the student is required
to pay tens of thousands of dollars.

-R.S.Hoover
-EAA 58400 (Life Member)

[[email protected]]

On Jan 14, 11:31*am, "J.Kahn" > wrote:
> If someone was to design a steel tube fuselage or a modification to a
> steel tube fuselage, does anybody know of a relatively inexpensive and
> painless way to get a stress analysis done, or software to do it?
>
> John

There is a free finite element program available for download from
this NASA website. They may ask for voluntary donations.

http://femci.gsfc.nasa.gov/links.html

The link on the page that I am talking about is the MYSTRAN link near
the bottom of the page. It is a finite element analysis program
written by Dr. Bill Case of NASA.
There are many other links that should be useful.

Regards,
Bud

[[email protected]]

On Jan 14, 11:31*am, "J.Kahn" > wrote:
> If someone was to design a steel tube fuselage or a modification to a
> steel tube fuselage, does anybody know of a relatively inexpensive and
> painless way to get a stress analysis done, or software to do it?
>
> John

Sorry, I got two links mixed up. This link

http://homepage.usask.ca/~ijm451/finite/fe_resources/fe_resources.html

has references that are free or donation asked. The MYSTRAN software
is $200 for a 1 year license. Cheap in the software world.

Regards,
Bud

[Charles Vincent]

wrote:
> On Jan 14, 11:31 am, "J.Kahn" > wrote:
>> If someone was to design a steel tube fuselage or a modification to a
>> steel tube fuselage, does anybody know of a relatively inexpensive and
>> painless way to get a stress analysis done, or software to do it?
>>
>> John
>
> Sorry, I got two links mixed up. This link
>
> http://homepage.usask.ca/~ijm451/finite/fe_resources/fe_resources.html
>
> has references that are free or donation asked. The MYSTRAN software
> is $200 for a 1 year license. Cheap in the software world.
>
> Regards,
> Bud

A Finite Element Analysis package is worse than useless without mastery
of the basics. If you can't do it by hand, what you get from FEA could
get you or someone else killed. EAA still sells "Stress Without Tears"
that takes you through the basic principles and simplified equations for
doing stress analysis of aircraft structures. If you can't master that,
you aren't going to do much better learning the ins and outs of meshing
for FEA.

Charles.

[[email protected]]

On Jan 14, 10:11*pm, Charles Vincent > wrote:
> wrote:
> > On Jan 14, 11:31 am, "J.Kahn" > wrote:
> >> If someone was to design a steel tube fuselage or a modification to a
> >> steel tube fuselage, does anybody know of a relatively inexpensive and
> >> painless way to get a stress analysis done, or software to do it?
>
> >> John
>
> > Sorry, I got two links mixed up. This link
>
> >http://homepage.usask.ca/~ijm451/finite/fe_resources/fe_resources.html
>
> > has references that are free or donation asked. The MYSTRAN software
> > is $200 for a 1 year license. Cheap in the software world.
>
> > Regards,
> > Bud
>
> A Finite Element Analysis package is worse than useless without mastery
> of the basics. *If you can't do it by hand, what you get from FEA could
> get you or someone else killed. *EAA still sells "Stress Without Tears"
> that takes you through the basic principles and simplified equations for
> doing stress analysis of aircraft structures. *If you can't master that,
> you aren't going to do much better learning the ins and outs of meshing
> for FEA.
>
> Charles.- Hide quoted text -
>
> - Show quoted text -

'Stress Analysis Made Painless' by Raoul J. Hoffman

Hand analysis can be made painless through simplified equations
available from somebody, whereas setting up a finite analysis input
file in order to let a computer do the calcs is beyond his grasp. GOT
IT! thanks.

Bud

[[email protected]]

On Jan 14, 11:31*am, "J.Kahn" > wrote:
> If someone was to design a steel tube fuselage or a modification to a
> steel tube fuselage,
>
> John

Now that the beers have worn off.....

does anybody know of a relatively inexpensive and
> painless way to get a stress analysis done

No!

Bud

[Charles Vincent]

wrote:
> On Jan 14, 10:11 pm, Charles Vincent > wrote:
>> A Finite Element Analysis package is worse than useless without mastery
>> of the basics. If you can't do it by hand, what you get from FEA could
>> get you or someone else killed. EAA still sells "Stress Without Tears"
>> that takes you through the basic principles and simplified equations for
>> doing stress analysis of aircraft structures. If you can't master that,
>> you aren't going to do much better learning the ins and outs of meshing
>> for FEA.
>>
>> Charles.- Hide quoted text -
>>
>> - Show quoted text -
>
> 'Stress Analysis Made Painless' by Raoul J. Hoffman
>
> Hand analysis can be made painless through simplified equations
> available from somebody, whereas setting up a finite analysis input
> file in order to let a computer do the calcs is beyond his grasp. GOT
> IT! thanks.
>
> Bud

Without a basic grounding in airframe stress analysis, how does one know
where to apply the loads and the vectors? How does one determine the
magnitude of the loads? Setting aside the learning curve for FEA and
the program, how does one know the solution is in the realm of possible
if you haven't applied any hand calcs beforehand? A comparison to a
second independent analysis method is generally part of the FEA process.

Finally, FEA is not simple. ISO guidelines suggest a minimum of five
years engineering experience and six months of post training FEA
experience for FEA work on critical structures. FEA texts will assume
you already understand stress analysis. The sources suggested by others
here for hand calcs of stress(other than Teichmann) do not In the
end, unless you are set on generating worthless pretty color pictures,
you will have to hit the hand calcs anyway.

Charles

Charles

[[email protected]]

On Jan 14, 11:31*am, "J.Kahn" > wrote:
> If someone was to design a steel tube fuselage or a modification to a
> steel tube fuselage, does anybody know of a relatively inexpensive and
> painless way to get a stress analysis done, or software to do it?
>
> John

Consider posting this question to www.eng-tips.com

[J.Kahn]

Charles Vincent wrote:
> wrote:
>> On Jan 14, 11:31 am, "J.Kahn" > wrote:
>>> If someone was to design a steel tube fuselage or a modification to a
>>> steel tube fuselage, does anybody know of a relatively inexpensive and
>>> painless way to get a stress analysis done, or software to do it?
>>>
>>> John
>>
>> Sorry, I got two links mixed up. This link
>>
>> http://homepage.usask.ca/~ijm451/finite/fe_resources/fe_resources.html
>>
>> has references that are free or donation asked. The MYSTRAN software
>> is $200 for a 1 year license. Cheap in the software world.
>>
>> Regards,
>> Bud
>
> A Finite Element Analysis package is worse than useless without mastery
> of the basics. If you can't do it by hand, what you get from FEA could
> get you or someone else killed. EAA still sells "Stress Without Tears"
> that takes you through the basic principles and simplified equations for
> doing stress analysis of aircraft structures. If you can't master that,
> you aren't going to do much better learning the ins and outs of meshing
> for FEA.
>
> Charles.

Don't see it on the EAA site but it is available on Amazon. Just what
I'm looking for.

Thanks for the input all!

John

[Charles Vincent]

J.Kahn wrote:
> Charles Vincent wrote:
>> EAA still sells "Stress Without Tears" that takes you through the basic principles and
>> simplified equations for doing stress analysis of aircraft structures. If you can't master that, you aren't going to do much better learning the ins and outs of
meshing for FEA.

> Don't see it on the EAA site but it is available on Amazon. Just what
> I'm looking for.
>
>

I figured you had just missed it on the site, but I can't find it there
either. Can't find any of Pazmany's stuff either. Or any of the other
decent design material that carried just a couple of years ago. All they
have that seems even close is "Practical Light Plane Design and
Construction for Amateurs" by Fike. Sixty whole pages. Wow.
Hopefully none of those pages are wasted on composite antenna design.....

Charles

[Evan Carew]

For anyone actually watching this thread who is interested in purchasing
the book, its ISBN is as follows:

ISBN-13: 978-0788113437

Evan

[Charles Vincent]

Evan Carew wrote:
> For anyone actually watching this thread who is interested in purchasing
> the book, its ISBN is as follows:
>
> ISBN-13: 978-0788113437
>
> Evan

Amazon is selling it used for $21. Aircraft Spruce sells it new for
$19. It appears that EAA may still sell it in the members area of their
website, but since I haven't upped mine again this year, I can't tell
for sure. The author, Tom Rhodes was a professional engineer that did
stress analysis for Republic on the reconnaissance version of the F-84F.
He later did stress analysis on the XB-70. The book, "Stress without
Tears" subtitled "A Primer on aircraft-stress analysis requiring no
advanced mathematics" was actually first published as a 42 part article
in "Kitplanes" in 1985. Rhodes actually went to the effort of having it
peer reviewed by other engineers in the field. It is not going to equip
you to do work for Boeing, but it will give you an understanding of the
basics and lead you into more advanced texts. A bargain at $20. It
appears that EAA may still sell it in the members area of their website,
but since I haven't upped mine again this year, I can't tell for sure.

Charles

[[email protected]]

On Jan 17, 9:40*pm, "J.Kahn" > wrote:
> Charles Vincent wrote:
> > wrote:
> >> On Jan 14, 11:31 am, "J.Kahn" > wrote:
> >>> If someone was to design a steel tube fuselage or a modification to a
> >>> steel tube fuselage, does anybody know of a relatively inexpensive and
> >>> painless way to get a stress analysis done, or software to do it?
>
> >>> John
>
> >> Sorry, I got two links mixed up. This link
>
> >>http://homepage.usask.ca/~ijm451/finite/fe_resources/fe_resources.html
>
> >> has references that are free or donation asked. The MYSTRAN software
> >> is $200 for a 1 year license. Cheap in the software world.
>
> >> Regards,
> >> Bud
>
> > A Finite Element Analysis package is worse than useless without mastery
> > of the basics. *If you can't do it by hand, what you get from FEA could
> > get you or someone else killed. *EAA still sells "Stress Without Tears"
> > that takes you through the basic principles and simplified equations for
> > doing stress analysis of aircraft structures. *If you can't master that,
> > you aren't going to do much better learning the ins and outs of meshing
> > for FEA.
>
> > Charles.
>
> Don't see it on the EAA site but it is available on Amazon. * Just what
> I'm looking for.
>
> Thanks for the input all!
>
> John- Hide quoted text -
>
> - Show quoted text -
If you are inclined to take a look at the real thing, not the Reader's
Digest version, you can download almost anything you want for free
from this site at NASA.

http://euler9.tripod.com/analysis/asm.html

There are also links to much more.

Regards,
Bud

[Charles Vincent]

wrote:

> If you are inclined to take a look at the real thing, not the Reader's
> Digest version, you can download almost anything you want for free
> from this site at NASA.
>
> http://euler9.tripod.com/analysis/asm.html
>
> There are also links to much more.
>
> Regards,
> Bud

That is fascinating Bud and I have actually reviewed it before. Somehow
though I have missed the section on the stress analysis of a steel tube
fuselage.

The books recommended by myself and others are primers. As such they
give the reader the needed context of where to apply a euler equation to
an airframe and how to apply it.

Charles

[Charles Vincent]

wrote:

> If you are inclined to take a look at the real thing, not the Reader's
> Digest version, you can download almost anything you want for free
> from this site at NASA.
>
> http://euler9.tripod.com/analysis/asm.html
>
> There are also links to much more.
>
> Regards,
> Bud

By the way, that is not in fact a NASA site, but a private site. The
NASA material can also be found on the NASA site though the last time I
looked. It is disheartening, but a lot of the NASA material (actually
NACA) has been made inaccessible in the last couple of years.

Charles