# Quick strengths question

• glid02
In summary, to find the deflection of a beam made of steel and brass, with different values for E, using the formula PL/AE, both materials must be considered together as they will deflect by the same amount under the applied load. The total area of the beam is 1.5m x 1.5m, with the force applied evenly on the end.

#### glid02

I'm supposed to find the deflection of a beam. It's steel with a brass shell, so they have different values for E. How do I do this problem using PL/AE.

Intuitively I think I should take the average, but I have no idea if that's right or not.

Thanks.

I should probably give some more information:
the steel part is 1m x 1m and the shell is 1/4 m on all sides, so the total area of the beam is 1.5m x 1.5m. The force is applied evenly on the end of the beam.

I thought maybe I should just use PL/AE for the material with the higher E value - steel - but the brass shell would have to have some effect on the deflection.

Last edited:
glid02 said:
I'm supposed to find the deflection of a beam. It's steel with a brass shell, so they have different values for E. How do I do this problem using PL/AE.

Intuitively I think I should take the average, but I have no idea if that's right or not.

Thanks.

I should probably give some more information:
the steel part is 1m x 1m and the shell is 1/4 m on all sides, so the total area of the beam is 1.5m x 1.5m. The force is applied evenly on the end of the beam.

I thought maybe I should just use PL/AE for the material with the higher E value - steel - but the brass shell would have to have some effect on the deflection.
When the beam is subject to the axial load P, part of that load is carried by the steel, and the other part by the brass. Both the brass and steel must deflect together by the same amount. Does that give you a hint as to how to proceed?

Yeah, that helps. I'll give it a shot and you'll hear back from me if I still can't get the right answer.

Thanks.