# Internal Forces in Coaxial Bars of Different Materials

• chandran
In summary, the conversation discusses two coaxial circular bars of different materials with a force of 30kN applied at the top. The speaker believes that the internal forces in both bars will also be 30kN. However, there is some uncertainty about the load being applied to both parts or just the inner one. The possibility of calculating the new diameter of the shaft and the potential interference between the two bars is also mentioned.
chandran
i have attached a doc file. it shows two coaxial circular bars of different material and a force(30kn) is applied in the top. I think the internal forces in both the bars
will be 30kn. Am i correct.

bar1 is made of steel and bar 2 of aluminium. the total length of the structure is
10metres.

No .doc file attached.

i have attached a jpg since memory was less.

#### Attachments

• coaxial.jpg
3.5 KB · Views: 351
I can't really make out the picture. I can't tell if the load is applied to both parts or the inner one. If you are asking what the compressive load is and the 30kN is applied to both bars, then you are correct.

As another possibility, you may also nee to look at this is with the application of the load to the inner shaft, which will compress according $$\Delta = \frac{PL}{AE}$$ Since the volume remains constant that should give you an ability to calculate the new diameter of the shaft. The same holds true for the outer shaft, simply using the constants for a different material. Once you have calculated the new diameters, chances are that there is an interference between the two. That interference will produce a contact pressure and thus an internal stress between the two.

## 1. What are internal forces in coaxial bars?

Internal forces in coaxial bars refer to the forces that are generated within the bar itself due to the application of external forces or loads. These forces can cause the bar to deform or change shape, and can ultimately lead to failure if they exceed the bar's strength.

## 2. How do internal forces differ in coaxial bars made of different materials?

The internal forces in coaxial bars can differ depending on the material properties of the bar. For example, a bar made of a brittle material such as glass will experience higher internal forces and is more likely to fail than a bar made of a ductile material such as steel.

## 3. What factors affect the internal forces in coaxial bars?

The internal forces in coaxial bars are influenced by several factors, including the material properties of the bar, the applied external loads, the geometry of the bar, and the boundary conditions at the ends of the bar. These factors can all impact the distribution and magnitude of internal forces within the bar.

## 4. How can internal forces in coaxial bars be calculated?

Internal forces in coaxial bars can be calculated using various equations and principles from mechanics, such as the equations of equilibrium and stress-strain relationships. Finite element analysis is also commonly used to determine the internal forces in complex bar geometries and loading conditions.

## 5. How do internal forces in coaxial bars affect the overall structural integrity?

The internal forces in coaxial bars play a crucial role in determining the overall structural integrity of a system. If the internal forces exceed the strength of the bar, it can lead to failure and compromise the stability of the entire structure. Therefore, it is important to consider internal forces when designing and analyzing structures that incorporate coaxial bars.

• Classical Physics
Replies
5
Views
219
• Classical Physics
Replies
9
Views
1K
• Classical Physics
Replies
10
Views
673
• Mechanical Engineering
Replies
8
Views
2K
• Classical Physics
Replies
1
Views
564
• Classical Physics
Replies
5
Views
4K
• Classical Physics
Replies
1
Views
659
• Introductory Physics Homework Help
Replies
12
Views
264
• Classical Physics
Replies
5
Views
621
• Engineering and Comp Sci Homework Help
Replies
2
Views
776