Fixed Leading Edge (FLE)

[oragutise]

Hello, as a stress engineer, I am working on fixed leading edge (FLE) of wing. I need details about how to analyze Ribs, skin, clips, etc.

Where can i find such reference details?

 

[SWComposites]

Your company's stress manuals

Niu, Airframe Stress Analysis and Sizing
Bruhn, Analysis and Design of Flight Vehicle Structures
Peery, Aircraft Structures

ask your lead stress analyst

take a class in aircraft stress analysis: UCLA Extension, University of Kansas, etc.

 

[40818]

Not sure wht typw of a/c your working on, or at what stage (concept, DFM, modification etc), but if your FLE then wing ribs probably wont be necessary. You should be able to stress clips???? shouldn't you.

More details will help guidance, but if your working for an OEM (Boeing/Airbus) either directly or tfor a sub-con company, then you should have access to the relevent data. If your working for a company purely doing mods, then its back to basics i'm afraid. Read books/papers etc and ask morew specific questions here if necessary.
You sound kinda new to the industry, i would recommend reading bruhn from start to finish then you will be in a good position.

 

[bf109g]

Birdstrike may also be an issue, depending on certification basis (if dealing with the FAA). Are there slats involved?

 

[oragutise]

work is not for Boeing or Airbus.
We need to design the wing from scratch.

It does not contain slats

 

[40818]

If your doing it from scratch (the whole wing) then you will probably have to go round the loop as it where. You will need to work out what type of wing, its sizes, shape etc and the operating environment (loadcases etc). Loading will be a big part of the story before you even start thinking about stressing with any conviction. I would recommend books along the lines of Raymer's.
Once you have a decent idea about the shape and the loading, then you can get on with the first stage of the concept. The you will have to move through various stages of design and iteration till you get to a DFM stage. Then you will have finished design calcs and sealed designs, so you can embark upon an independent checkstress activity.
Oh the fun.........
Seriously though depending upon the aircraft size and complexity it could be a hard slog for you.
A word of advice though, sort the loading out, because it can and does come back to haunt you in the later stages and make you have to shapren your pencil.

Any more detail you could give and maybe could give advice on the detail analysis.

 

[oragutise]

40818, thank you.

Part i would be interested at the moment are designing ribs and clips. loadcases have already been done by others.

Now i need to hand calculate using the loadcases.

 

[40818]

Do you mean wing ribs or more of a "D" shape diaphragm forward of the front spar?

 

[oragutise]

region between nose of wing till web of front spar

 

[SWComposites]

Do you have the references I listed above?

If not, buy/obtain them, read the relevant sections, then ask specific questions.

 

[oragutise]

Yes Sir, i have the books u have listed.
there are alot of materials, wish if you could list down few important tops.

 

[40818]

Probably the most important tip is to get the design/analysis right. There are 2 ways to make this happen, the first is luck,and the second is to know what your doing. The best way to know what your doing is to research the problem by reading the literature.

You have to read the books to understand the problems, we dont know what sort of knowledge level your actually at, but you must try to give specific problems you encounter as there is simply to much to generalise upon.

What sort of aircraft are we talking about? things like this help. Have a think about your actual problem, it might be having problem working out the shearflow on your panel structure and subsequently whether it buckles due to shear under proof loading etc.

Theres no easy route i'm afraid, but everybody here has been in the same boat, and the onlyway out is to read the books.

 

[oragutise]

I am new to this field. its an aircraft for less than 10 people.

i have come across shearflow, but dont exactly still know what does it exactly mean. kindly explain me please 40818

 

[40818]

Before you can run you must be able to walk, and even crawl before that.
Dont even start with Niu, Peery or Bruhn, get a mechanics of materials/strength of materials book and start at the front page. Once you understand basic principles then you can maybe start to apply them to structures.

 

[RPstress]

As 40818 says, looking at your query about shear flow, then it appears that you're barely at the stage of using P/A (unless perhaps there are some language difficulties). You probably need some experienced people local to your team to learn from. I don't think this sort of internet forum is really suitable to such general basic education. By the way, shear flow (q) is shear per unit length, which is also shear stress times thickness.

 

[mohr]

Hi Oragutise :

Paul Kuhn from NACA did some works you can find at NASA Tech server and may help you (box analysis,cutoff,diagonal fields, shear lag, etc) plus all literature cited here such as Bruhn,
Niu and others.

Do a work hypothesis and discuss it whit a people near you as
RPstress said, always with a conservative criteria and good sense.

Cheers

 

[oragutise]

Thank you mohr!

 

[rb1957]

i fear your company has placed you in an unenviable position (not knowing how to do the task assigned) and is going to lose a whole bunch of money in this effort. all the texts and NACA references in world are only data ... that is information without understanding.

if you're going to hand calc the wing, i'd start with Bruhn, it's a big book full of relevent analysis and considerations. but no book is going to tell you everything you need to know, we've already had a few thoughts (like birdstrike) but there's fatigue and literally a million other things (how are you going to build it? have you looked into FAR23 yet??).

good luck, but i have a sense of impending doom (if this is a real plane, and not a design project).