|
||||||||||||||
|
||||||||||||||
| question on material deflection |  |  | |
| Post Reply | Forum | ||
| Posted by: mark.rowe4 ® 04/20/2008, 13:19:31 Author Profile eMail author Edit |
I have a challenge for all you budding engineers our there I have a piece or 304 steel used in an application where it is used in part of a seat The shape is roughly an L shaped bracket about 6 inches per leg with a bend just below 90 degrees and on each end about 2 inches in the metal is bent up (the opposite way to the 90 degree) about 4 degrees the flat bar is 25mm by 5mm roughly about 18 inches total in length the problem is that with some one sitting on this part repeatedly the material bends past its elastic limit and permanently deforms is am looking at a way of working out the yield point so i can select a different material which wont bend permanently (it must go back to the original shape) i can use any metal (with in cost realism) but it must not go past the yield point or enter the plastic region any ideas how this can be calculated with thanks
|
| Post Reply Tell a Friend (must be logged in) Alert Admin About Post |
View All | Previous | Next | Current page |
| Replies to this message |
| : question on material deflection | | ||
| : question on material deflection -- mark.rowe4 | Post Reply | Top of thread | Forum |
| Posted by: hardcoreengineer ® 05/03/2008, 00:06:30 Author Profile eMail author Edit |
if you are not pickey about material go get some t6 6061 alum. and use that it should give you plenty of spring back but dont give it a small radius when you bend it it may crack one way to combat that is to line grain it first |
| Post Reply Tell a Friend (must be logged in) Alert Admin About Post |
Where am I? Original Top of thread | Previous | | Current page |
| : question on material deflection | | ||
| : question on material deflection -- mark.rowe4 | Post Reply | Top of thread | Forum |
| Posted by: sudhakar.s ® 05/02/2008, 03:37:45 Author Profile eMail author Edit |
1.use i-beam which will have more MI.. select i beam or higher web length. this beam can take more load than existing. 2. use stiffner or trusses which will increase the stifness without changing the material.. Modified by sudhakar.s at Fri, May 02, 2008, 05:01:02 |
| Post Reply Tell a Friend (must be logged in) Alert Admin About Post |
Where am I? Original Top of thread | Previous | Next | Current page |
| : question on material deflection | | ||
| : question on material deflection -- mark.rowe4 | Post Reply | Top of thread | Forum |
| Posted by: jboggs ® 04/20/2008, 13:47:06 Author Profile eMail author Edit |
Well as a first effort, you might examine just making the bracket out of thicker material. The problem is that you really don't know what the actual loading is. So either calculate it, or set up tests of various design options. You might look at ways of stiffening the material at the bend (a weldment, a bolted joint, fillets). I assume that is where it is failing. |
| Post Reply Tell a Friend (must be logged in) Alert Admin About Post |
Where am I? Original Top of thread | Previous | Next | Current page |
| : : question on material deflection | | ||
| : : question on material deflection -- jboggs | Post Reply | Top of thread | Forum |
| Posted by: mark.rowe4 ® 04/20/2008, 14:02:26 Author Profile eMail author Edit |
yes my problem is that the loading on the seat can be anyone with differing weights and sizes i was going to try to figure out the yield point and then pick a stronger material say double the compressive strength (i assume) i can not really change the shape it has to be flat both sides so i can not add anything to strengthen the bend either as the design has fabric both sides regards
|
| Post Reply Tell a Friend (must be logged in) Alert Admin About Post |
Where am I? Original Top of thread | Previous | Next | Current page |
| : : : question on material deflection | | ||
| : : : question on material deflection -- mark.rowe4 | Post Reply | Top of thread | Forum |
| Posted by: jboggs ® 04/20/2008, 14:09:14 Author Profile eMail author Edit |
I assume the bar is stainless for a reason. If so, there are stiffer grades of stainless steel. There are alos much stiffer grades of carbon steels. Any good steel supplier book should have the information you need. |
| Post Reply Tell a Friend (must be logged in) Alert Admin About Post |
Where am I? Original Top of thread | Previous | Next | Current page |
| : : : : question on material deflection | | ||
| : : : : question on material deflection -- jboggs | Post Reply | Top of thread | Forum |
| Posted by: mark.rowe4 ® 04/20/2008, 14:23:31 Author Profile eMail author Edit |
this is what i thought and told my mate that the simplest way would be to increase the thickness thus increasing the strength (lack of bend ability) or change the material for a stronger one but the same size is there any way of working out say the difference between 5mm thick and 8mm thick (10mm is a bit thick for application i think)so i could say that the original will bend at X and the new will bend at Y Regards
|
| Post Reply Tell a Friend (must be logged in) Alert Admin About Post |
Where am I? Original Top of thread | Previous | Next | Current page |
| : : : : : question on material deflection | | ||
| : : : : : question on material deflection -- mark.rowe4 | Post Reply | Top of thread | Forum |
| Posted by: jboggs ® 04/20/2008, 14:29:01 Author Profile eMail author Edit |
In theory the 8mm will exhibit 160% of the stiffness of the 5mm. But the complications of the bent shape and other application factors may negatively affect the actual performance. The only way to know if it will work for you is to try it. |
| Post Reply Tell a Friend (must be logged in) Alert Admin About Post |
Where am I? Original Top of thread | Previous | | Current page |
