I am building a pneumatic shear to cut .135" C1018 round wire. We will be holding the wire in a hardened thimble and using a heat treated beveled cutting knife.
How much force do we need to be able to produce?
1
-
$\begingroup$ Is the diameter 135 inches or 0.135 inches ? i see a dot before number one! because the force i calculated is unbelievably big, and ingot is the correct name for 135 inches not wire. $\endgroup$– user14407Sep 26, 2018 at 16:36
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
I use to build a very simple model first, then try to expand it. Here i try to find the minimum, force require to cut the wire, by using Tresca criterion:
Yielding starts when the maximum shear stress in the material $\tau_{max}$ equals the maximum shear stress at yielding in a simple tension test $\tau_x$. You can verify the final result with the Mohr's circle: $$\tau_{max} = \frac{\sigma_y}{2}$$
Here $\sigma_y$ is the yield strength of your material. A quick google search, i find the yield strength of $370 MPa$.
Now, the force: $$\tau_{max} = \frac{F}{A}$$
$\tau_{max} = 185 Mpa$ and the section area of the wires are about is about $37 m^2$. The require force is about $6845 MN$.
I worked so far conservative, by using other criteria, you may find much lower values for the force, i think, but you have to make sure if the force is enough to cut through the wires.