Training - Aircraft Structural Analysis 16

SAITAETGrad... My bible is the MIL-HDBK-5 [now MMPDS]... with Bruhn running a close second.

In ~1973 I was taking one of my first stress courses. The instructor decided to teach from 'course notes', 'to save us the expense of buying another textbook'. Every couple of weeks we received one or two packages of photocopied 'course notes'. This guy was a real theorist and had a complex writing style: what a nightmare trying to sort-out stress with his overly simplistic sketches and long equations!

One day I was down-town SLO and discovered a used book store… and was soon poking around the engineering texts. Guess what I found: a ‘gently used’ copy of Bruhn, 1965. I remember standing there thumbing thru page after page till I had to pee so bad I could hardly stand it. In that +hour of thumbing, 2-months of stress class came into sharper focus. I paid the grand sum of ~$25 for that book and never regretted it. Needless to say every topic the instructor covered, I reviewed the same topic in Bruhn... only to realize that Bruhn was far more concise and to-the-point... and had really good illustrations!

One afternoon it all came-to-a-head when I was called to his office to explain why I had NOT used his course-note techniques for solving a multi-cell torque/bending problem... but had used the much simpler format laid-out by Bruhn [remember this guy was a theorist]. I proposed we go to the aero-dean and discuss why an alternate solution from Bruhn was unacceptable relative to his 'course notes'. It was then that he relented. Found-out that a few other classmates had talked to one of the higher-level stress instructors about the course and his exclusive use of poorly written 'course-notes'. It was then that we heard he was supposed to be teaching from Perry's Aircraft Structures or Bruhn's text; and that his 'course notes' were actually sections/chapters from a stress-analysis text he was writing. Grrrrr... but thank God for Bruhn.

However, in BRUHN, I quickly found a few pages of metals data tables extracted from a mysterious document... numbered 'MIL-HDBK-5’... which seemed to present actual/authoritative mechanical allowables for real metal materials! I found a copy of MIL-HDBK-5A METALLIC MATERIALS AND ELEMENTS FOR AEROSPACE in the library... and realized that all the theory boiled down to how real metals and fasteners actually perform in-service… and here were real numbers!!! What hit me hard was that NONE of my courses or instructors had ever mentioned MIL-HDBK-5! In almost every case we were ‘given numbers to plug into the equations’ and told “where they came from was not our concern at the present”. The second major expense I had was paying $40? for a new copy of MIL-HDBK-5B mailed from the GPO. When it arrived, I fell in-love airframe with metallic materials, which has turned-out to be a thorn covered rose: many bloody lessons still were to be to learn about materials, specifications, testing, etc... but I had started.


Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true.
o For those who believe, no proof is required; for those who cannot believe, no proof is possible.
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion"]
o Learn the rules like a pro, so you can break them like an artist. [Picasso]

Wil,
Thank you for the story. Resonates with me and, I'm sure, many others who will read it.

This would also make a good preface of the book you are destined to write!


SAITAETGRAD,
I see that Simon's back on the warhorse. Excellent! Since I frequently find myself thumbing through Bruhn at work I don't think I could stand evenings doing the same thing, but I will recommend the course to others who are on the verge of learning aircraft-related topics in structural analysis but still relying on standard ME training.


STF

Hi Gents,

A very interesting thread this. At my workplace I have been tasked from time to time to give short courses to newly-graduated engineers. College training in aero structures lacked two very important topics: Fasteners and the concept of a load path. One particular "student" was scornful of having to learn the stressing of lugs, this being beneath his dignity. I told him to go and look at real aircraft to see how important the lowly lug was. Sigh.

Andries

wkTaylor, Bruhn was our principle text for us 'SAIT Aero Eng Tech' three year diploma types. Simon was our instructor and the course mentioned above was our first of three courses from Bruhn. In Bruhn we Trust!

Andries, Bruhn D1 and D2 are part of this first course.

For $750, great value. Right now that's less than $600 USD.

Way back in 1971 I paid the equivalent of US$15 for my copy of Bruhn.
(Wil,looks like I'm older than you!)

Andries

Howdy all,

So I was looking at Amazon.com for a copy of this book and I noticed that Bruhn has 2 books. One call 'Analysis and Design of Aircraft Structures' published in 1944 and 1958 and 'Analysis and Design of Flight Vehicle Structures' published in 1965 and 1973. I'm no book collector (well I've got a lot of books, but hey how doesn't) but before I drop a significant chunk on one of these books I want to make sure I'm getting the right one. Is there any reason to purchase anything other than the 1973 version? I know there's a significant errata file for the Bruhn available for download; has the errata been incorporated in the 1973 edition?

Simon,

I am interested in taking this course. I'm located in Oklahoma. I don't know how to verify testing from such a distance. I also don't really need an official certificate. Can I audit the course and just dispense with having a proctor? (BTW learned a new word - invigilation. Thanks.) I intend to meet the requirements of the testing, since doing otherwise would be cheating myself.

Thanks for your help.

-Kirby

Kirby Wilkerson

Remember, first define the problem, then solve it.

I've got the '43 or '44, '58,and '73 versions. The '73 is the latest, and I suspect that is what the class identified by the OP will use. If you plan on working biplanes and old technology, get the '43 vintage book. The data for biplanes was removed, but additional material was added to the '58 version. There are also '46 or '47 versions out there.

You might also want to download the Bruhn errata from Gran Corp.

@Kirby ... "Analysis and Design of Flight Vehicle Structures".

also remember McCombs "supplement"

another day in paradise, or is paradise one day closer ?

I was one of the last students to take a class under Prof. Bruhn at Purdue before he retired in the early 1960's...
G-pa Dave

Probably the single most valuable thing that has come from the internet is the opportunity for anyone who truly wishes, to get a university level education at no cost thanks to these online courses.

However, the point made about simply learning the analytical approach to use for a structure without having a good knowledge of material properties is excellent. For example, many aircraft structural components are shot peened which greatly improves fatigue performance. But how would you know what effect this would have on your analysis unless someone explained it to you?

MMPDS is easily the best overall reference for mechanical properties of metallic materials used in aircraft structures. But you still need to have an extensive understanding of things like manufacturing processes, corrosion protection, heat treatment, etc to make use of the information contained in MMPDS. And the only way I know of to accumulate this specific knowledge is by spending lots of time working in the industry.

Great topic!

I have started a similar effort and it is all online. My focus presently is on cabin interiors. If you feel you have extensive experience in primary structures and composites stress analysis at a level where you consider yourself a proven expert, please reach out to me. Here is the most recent blog post I wrote, please feel free to comment and let me your feedback.


Aerospace Stress Analysis and FEA Courses
Stressing Stresslessly!

A clarification may be necessary:
The OP (member SAITAETGrad) is not the instructor, he is letting the Eng-Tips community know about this course, which being offered by his former teacher Simon Bergen-Henengouwen. I think he posted the link just to help out a friend, colleague, and mentor (as I would also be glad to do on Simon's behalf). I have informed some of my co-workers about the course, which is what I think SAITAETGrad was doing too.

StressbookLLC, Kirby, and others,
Simon would probably he happy to hear from you, but as far as I know, he is not signed on to Eng-Tips. You should feel welcome to contact him directly with your inquiries.

(I am only stepping in to point this out because I believe SAITAETGrad doesn't check in at Eng-Tips as often as I do, and I don't want the misunderstanding to persist. I know these two people personally, so I hope they can understand why I am speaking for them).

STF

I learned much more from Bruhn,I have both editions from Amazon.com,on by own than nine trimesters at Parks Air College.I don't know the course work required now,but in my days back in early 70's,the structural analysis and design courses really lacked.Here again the texts selected by the instructors were not good,their class notes even worse,a sad sight for one truly interested in structures.I now after many years have accumulated a decent library,thru used book stores.Hopefully the tmes I went thru have been improved upon.

I have corresponded with Simon Bergen-Henengouwen. It looks like the cost and time frame are not going to work out for me this time around. Perhaps the next time he offers this course things will line up better.

tbuelna said:

Probably the single most valuable thing that has come from the internet is the opportunity for anyone who truly wishes, to get a university level education at no cost thanks to these online courses.

Click to expand...

I totally agree. The quality of available free online education has greatly improved. The course level has increased as well. It used to be you could get plenty of help for basic maths, and most elementary and secondary education subjects. Now there are excellent lower level undergraduate courses in most subjects. I'm looking forward to some higher level courses being presented, partly as prep to see if I still have what it takes to go back for a graduate degree and to do some revising to make sure I can remember everything from my undergraduate degree.

My current go to web site for education is edx.org. Good interface and a nice selection of courses from a broad array of topics. Just finished a Calculus I course which I remembered well, mostly, though the presented some topics in more depth than I had been exposed to before so there was some genuine new ground covered.


Kirby Wilkerson

Remember, first define the problem, then solve it.

NOTE.

One element that Bruhn missed, is what does real structure look like in preparation for analysis.

I have to admit, various liaison courses I've taken... and books like Niu's Airframe Structural Design ... are the next necessary step in a great training regimen.

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true.
o For those who believe, no proof is required; for those who cannot believe, no proof is possible.
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion"]
o Learn the rules like a pro, so you can break them like an artist. [Picasso]

One thing really lacking in all the aero structures courses I am familiar with is down to earth practicality.The reason I chose Parks Air College of SLU back in the late 60's & early 70's was its goal to apply design engineering to the real world.For example it was mindless to design a super compact engine block,and yet not allow for mechanics to be able to reach the cylinder hold down nuts.I still see today many a young EIT's with gobs of course work,but lacking in practical experience.Their college course work needs to be coupled with practical on the job experience,be it in a lab running along with the lectures or better yet real world experience you get on the job,yes work.Purdue and Parks College both at one time went this route.As times have changed and students desires changed thus so has the learning experience,maybe for not the better.Maybe the way that we learned was not the best,but from what I have seen recently of AE students,I am of the opinion that more down to earth subject matter should be taught and less canned software courses provided.Anyone agree ?

MOHR1951, I went to Parks also, stated out in Aircraft Maintenance Engineering, and that program was a good mix of practical and theoretical. Unfortunately my math background wasn't as good as it should be, so I switched to Aircraft Maintenance Management class of '78. My Parks education has served me well. Hated to see the A&P along with AMM and AME programs go down the drain in the early 2000s. My daughter also went to Parks, AME class of 2000.

Online education is a huge threat to the University system and they either have to join in or perish. And all the Ivy League schools have joined the bandwagon with their own versions of MOOCS, to name one, and my shameless plug for just to name a few.. this is exactly why I started my own site to teach and make passive income on the side... anyone can dream it, only a few can do it.

Aerospace Stress Analysis and FEA Courses
Stressing Stresslessly!

The problem I have with online education,applied to the engineering world is its passive nature.Havinr been taught in Statics 101 that to really understand technical theory it was necessary to work the problems.The more problems the students did,usually the greater the understanding of the material.The internet is great,I wished I had it growing up and through college,things are here that I only dreamed of seeing one day,a great resource.The drawback,in engineering education is its passive mentality.Much too easy to sit and read the lectures without forcing oneself to actually work through the calculations.This is the advantage a traditional university setting will always have over a net based education.I'm already seeing it,when I ask,for example,if the kid listened to the Khan lectures I am told yes,when I aske how many sample problems did you work through,I get that big blank grin.To learn engineering one must work the problems,without this its as if reading a storybook.