Calculating Poisson's ratio

Hi, im new to this so bear with me,

I'm stuck on a question, basically, i need to work out the poissons ratio for a solid cylinder 140mm dia by 4.0m long to find out if it's steel or aluminium. I know the formula for poisson ratio is lateral strain / axial strain. The question states that there is a force acting on the cylinder but gives no values, how would I go about working out the poisson's ratio? Any help would be much appreciated.

Many Thanks
Scott.

Astronuc
Staff Emeritus
Does the problem provide stresses or strains, and the elastic or bulk modulus?

One would need to know the axial and lateral strains, or a force/stress.

Please write the problem as given.

the whole question

A circular cross section tie rod located in a structure has a diameter of 140mm and a length of 4.0m. If under load the length increases by 1.2mm and the diameter decreses by 0.11mm, identify the relationship between lateral and transverse strain and determine the value of poisson's ratio.

I have no idea how to go about completing this one. Any help would be greatly appreciated.

Morrai Waram
FredGarvin
What is the definition for strain? You have two things you need to calculate in order to calculate Poisson's Ratio, the axial strain and the lateral strain. You are given all of the pieces of the two parts. What two numbers will make up the axial strain? What two numbers will make up the lateral strain?

continued...

the strain formula is: change divided by original

the 4.0m & 1.2mm increase is for the lateral strain and the 140mm and 0.11mm decrease is for the axial strain i beleive.

FredGarvin