Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations KootK on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Mathcad - Empirical Equations 2

Status
Not open for further replies.

EngineerRam

Structural
Jul 31, 2014
50
Hi,

For all engineers who use Mathcad:

For example:

If I were to define fc := 4000psi

How would Mathcad perform the following function for the elastic modulus?:

57000(fc)^0.5

I know Mathcad is smart in terms of performing unit conversions seamlessly, but what about equations where a specific unit is required to obtain a desired result? Is there a way to "hardset" the input unit? Also, is there a way to "hardset" the output unit for empirical equations where the output units don't necessarily equal the input units (such as the formula for the elastic modulus)? Or would I need to apply a unit to the constant portion so that the units equal?

Thanks
 
Replies continue below

Recommended for you

Just multiply by the value 1 with whatever unit is needed to get the final units you need. For your case, I would multiply the equation by sqrt(1 psi), which would let MathCAD give you a result in psi.
 
psi_n33cao.png


would be the way I'd do it. This allows the equation to be used with whatever unit system you might use. So, you could input the quantity in psi and do the post-fix conversion to pascal or bar, for example.

psi2_moxmhk.png


TTFN
I can do absolutely anything. I'm an expert!
faq731-376 forum1529
 
I tend to just multiply fc by psi. So it looks like 57000*(fc*psi)^0.5, does the same thing as the method mentioned by IRstuff.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor