I made a shear and moment diagram plot in mathcad and it should look like this:
However, in mathcad, mine is looking like this:
The problem, in particular is that on the moment diagram at about x= 1" there's a "knee" in the moment diagram that shouldn't be there.
Does anyone know the cause of the "knee?" Anyway to increase the resoltion of the plot?
You don't show how x is defined, but looking at the graph I'll guess it's a range variable 0*in,1*in..15*in. So you get a point every 1 inch. Make the increment much smaller, say 0*in,0.01*in..15*in.
If that's not the problem, please post a worksheet.
It's clearly a resolution problem. Presumably a low resolution has been set because the Moment integration takes too long otherwise. But the integration is simple to do analytically, so:
If you set n to 20 in the above you get the same corner cut-offs in M as in your original.
Don't rely on the quickplot feature of Mathcad. It gets lots of people into trouble. Use a range variable to define the x-axis range and increment.
Maybe that is a flaw with the quickplot feature. I think the user should be able to change the quickplot scale, to allow as in this instance, the increment to be reduced.