Is it possible to do this without Poission's ratio?

AI Thread Summary
The discussion centers on a problem involving a steel alloy bar experiencing elastic deformation, where the goal is to determine the force required to achieve a specific diameter reduction. Participants debate whether it's feasible to solve the problem without knowing Poisson's ratio, which is typically necessary for relating axial strain to lateral strain. The key equations mentioned include stress, strain, and Hooke's law, but the absence of Poisson's ratio complicates the solution. One participant suggests assuming a Poisson's ratio of 0.3 to proceed with the calculations. Ultimately, the consensus leans toward the necessity of Poisson's ratio for an accurate solution.
Nodnarb98
this is the problem as our professor gave it to us

"A steel alloy bar (modulus of elasticity of 205 GPa) is 20mm in diameter and experiances an
elastic deformation by applying a force along its axis (IE pulling it apart perpendicular to the
circular cross section). Determine the force needed to cause a .003mm diameter reduction."
is it even possible to do the problem without the ratio? if so where do I start?

2. Homework Equations
I Know stress =f/a, and strain = Δl/l and hooke's law σ=Eεz. as you can see he didn't give us possion's ratio, used in εz=-εx/v.

The Attempt at a Solution


I've tried setting it up multiple ways, but each time i have more unknowns that equations. I emailed my instructor but he hasn't answered

Thanks!
 
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In my judgment, you need to know Poisson's ratio. Assume 0.3
 
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