How do I calculate the length of a rod?

[exibo177]

Homework Statement

I need to calculate the breaking point of a Steel rod.

Homework Equations

I know the density: 8.03
Cross section: 1m^2
Tensile Strength: 500*10^6
Volume: 62266500.6
The whole length is: 406700

The Attempt at a Solution

Please provide me with explanations and equations which i could use. Thank You.

 

[LawrenceC]

You must attempt a solution before we will help. Furthermore, your problem is vague. How is the rod situated?

 

[exibo177]

You must attempt a solution before we will help. Furthermore, your problem is vague. How is the rod situated?

I don't have an attempt at a solution because i don't really know what to do at all. There is no information given except for what i wrote above, that's why i have a big problem with solving this..

 

[losttongue]

Material Science right?

You seem to be asking two questions the length of the rod and the breaking point of the steel correct?

If you are wondering about the breaking point of the steel it is a trick question the tensile strength is the maximum stress that may be sustained by a structure in tension (it is the top point in the stress/strain curve). If this stress is applied and maintained fracture will result.

so the tensile strength is the breaking point of steel.

As for the length of the rod, you have the whole length written up there as 406700. Units would help with all your data.

I have a few formulas that would work for this problem but with your given information it looks like a 100% trick problem.

Furthermore, your problem is vague. How is the rod situated?

It would be placed in a tensile testing machine, (most if not all of the time vertical) with two crossheads to attach the specimen.

 

[cupid.callin]

Hi
I have attached a pic i found of stress strain curve of mild steel,
Here, the breaking point's stress is given less that maximum stress ...

EDIT: Forgot to add pic ...

http://pages.uoregon.edu/struct/courseware/461/461_lectures/461_lecture24/461_lecture24_pic1.gif

 

[losttongue]

Hi
I have attached a pic i found of stress strain curve of mild steel,
Here, the breaking point's stress is given less that maximum stress ...

EDIT: Forgot to add pic ...

If you were to give me that value of stress and I were to look at the chart I would still be at the left side of the curve. How did you get to the right side of the curve?

The tensile strength is the breaking point, unless the problem has a chart along with it with time through the experiment with the corresponding stress on the specimen. This is the answer they are looking for.

As an engineer if your design reaches the tensile strength is a broken plastic deformed mess.

You understand that the slope reaches a max (tensile strength) and then begins to slope down, because the steel has already fractured. Metals are a ductile material though they do not crack into two like a brittle ceramic dinning room plate would. It bends first and the fracture grows, until the fracture is complete and it is in two pieces.