1. Jan 7, 2010

### elephunk

1. The problem statement, all variables and given/known data

Stuck on this for quite some time.

http://img685.imageshack.us/img685/1387/22580211.png [Broken]

2. Relevant equations

3. The attempt at a solution

I've drawn the component parts in question. Don't know where to even begin to find this solution (dont have my scanner here too). I am assuming I need to work out the CSAs of all the materials then move on from there? Need some assistance.

Thanks,

Last edited by a moderator: May 4, 2017
2. Jan 7, 2010

### nvn

elephunk: Cross-sectional areas are one thing you need. Read a few pages in your text book to find out how to compute the different types of stress. You must list relevant equations yourself, and show your work; and then someone might check your math.

3. Jan 8, 2010

### elephunk

Can you suggest two textbooks I can find this in? I've got technology of engineering materials and mechanical engineering principles and they dont appear to go in depth with stress.This is unlike anything I've done before and I've been searching for the information for days.

I've calculated the CSAs.

Steel CSA = 0.1mm^2
Timber CSA = 0.3mm^2

Thanks

4. Jan 8, 2010

### nvn

elephunk: Your cross-sectional areas are currently incorrect. Try again. Applied stress in this problem is force divided by area. Compare that stress to the given material strength by dividing the applied stress by material strength, which is called stress level, R. The highest stress level governs (fails first). Also, per the international standard (ISO 31-0), always leave a space between a numeric value and its following unit symbol. E.g., 20 mm, not 20mm. Also, N/mm^2 is called MPa. Always use the correct unit symbol (MPa in this case), if a derived unit has a special name.

5. Jan 9, 2010

### pongo38

1. You need to be clear about the distinct meanings of s t and tau
2. The end distance given has a clue to another failure mode

6. Jan 10, 2010

### elephunk

Steel = 20x5 - (5x5)= 75 mm^2

timber = 20x15-15x5= 270 mm^2

brass = pi*D^2/4=19.625 mm^2

Those are the CSAs. So from then on what do I do with the tmax and smax values. I didn't quite understand what you mean?

This is so confusing for me sorry.

7. Jan 10, 2010

### nvn

Your cross-sectional areas are incorrect. The diameter of the rivet is 10 mm. Try again. After that, compute the stress on the cross-sectional areas. The third sentence of post 4 tells you how to do that. You must list relevant equations yourself, and show your work. We are not allowed to give you the equations nor do your school assignment for you on this site. If you do not understand a particular sentence, explain exactly which part of the sentence or words you do not understand, and explain why you do not understand the words.