50Cent
Jan13-10, 10:41 AM
1. The problem statement, all variables and given/known data
Given two wires of guage length 100mm and 200mm
They are loaded to fracture in tension
The 100mm sample extends by 15mm
The 200mm sample extends by 25mm.
I need to use this information to calculate the nominal strain at which necking commences in the wires
2. Relevant equations
These are the relavent equations i can find in my notes relating to necking, stress/strain, true stress/strain
http://i47.tinypic.com/f42u0j.jpg
we are also told, the true stress/strain curve generally represented by,
http://i50.tinypic.com/fo1xmd.jpg
where n is the work-hardening exponent
"necking" in a sample started when the value of the true strain is equal to the work hardening exponent, i.e.,
http://i47.tinypic.com/2cxvrwm.jpg
3. The attempt at a solution
Im not so sure where to start with this as there are no forces given or areas. I assume we have to use the two sets of data to equated these terms and cancel them out.
Given two wires of guage length 100mm and 200mm
They are loaded to fracture in tension
The 100mm sample extends by 15mm
The 200mm sample extends by 25mm.
I need to use this information to calculate the nominal strain at which necking commences in the wires
2. Relevant equations
These are the relavent equations i can find in my notes relating to necking, stress/strain, true stress/strain
http://i47.tinypic.com/f42u0j.jpg
we are also told, the true stress/strain curve generally represented by,
http://i50.tinypic.com/fo1xmd.jpg
where n is the work-hardening exponent
"necking" in a sample started when the value of the true strain is equal to the work hardening exponent, i.e.,
http://i47.tinypic.com/2cxvrwm.jpg
3. The attempt at a solution
Im not so sure where to start with this as there are no forces given or areas. I assume we have to use the two sets of data to equated these terms and cancel them out.