you have a alloy. it has a 75GPa elastic moduls and it has been determined to have  215MPa of yeild strength. if your material has linear elastic stress-strain, figure out what the modulus of resiliance is for your alloy in J/m^

6.27 Compute the dislocation density in tungsten if the flow stress is controlled by the stress necessary to operate a Frank--Read source. The shearstress in the slip plane is 50 MPa. Take G = 166 GPa.

This is a follow up to my question and the answer you submitted. The equation you used for J is wrong, not sure how you got J=π32×Do4-Di4, the equation should be J=π/2×ro4-ri4 which is J=pi/2(50^4-40^4) = 5.8e+6 mm^4

3. Assume the plane stress state: ơ1 = 0, 02 = 20, T12 = 15 (all stresses in ksi). If oz alone is increased until the maximum shear stress t1, in the material reaches ±20 ksi, what is the value of o, at this point? HINT: this is relatively easy to figure out if you construct a Mohr's circle for the initial stress state and then consider what happens if o, is replaced with Ao2 and you solve for A when the maximum shear stress (from the circle geometry) reaches ±20 ksi.