INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

MATHCAD 15.0 Units problem

MATHCAD 15.0 Units problem

(OP)
This is my spreadsheet for flat slab design:

The demand and capacity moments moments seemingly have same units( all in ft.kip or ft.lb), however they are not comparable according to the program's error message.
the moment demand is Mu.str_pos is in <ft.kip> uints, while ϕMn.pos seems to be in <ft.kip> in the calculation equation per reinforcement and section geometry. however, if I output ϕMn.pos again, it is in <ft.lb>, and if I use units conversion tool try to change to <ft.kip>, it changed into "sec^/ft*ft.kip.

I highly appreciate your answer.

File attached

RE: MATHCAD 15.0 Units problem

I guess I probably could have guessed without the file(s); In Mathcad, as in real life, there is a tendency to elide part of lb-mass or lb-force when using "lb." While verbally understood, Mathcad is exact and unforgiving when it comes to units, which is its strength.


kip is 1000 lb-force, not lb-mass, which is not how you defined kip and ksi on your reference sheet. When these are corrected by replacing "lb" with "lbf" you get an "ok" for the answer

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers

RE: MATHCAD 15.0 Units problem

(OP)
Thank you very much! IR

RE: MATHCAD 15.0 Units problem

(OP)
one more question, why the variables defined in the referenced file( for barrier design) doe snot carry over to my mathcad sheet properly? it seems that my mathcad sheet doe snot recogize these variables already defined in the reference file.

RE: MATHCAD 15.0 Units problem

(OP)
IR, Thank you so much for your help.
I was trying to design the negative reinforcement for the slab using the barrier design results( the vehicle impact force and moment etc. from the reference file for barrier design). none of the barrier design results can be carried over and recognized by the slab design sheet. The variables that I was trying to be used are : Lci, Lce, M.cint,M.cend,A.barrier,cgx.barrier.

I have no problem to use the variables defined in the other three reference files.

RE: MATHCAD 15.0 Units problem

Are you sure that file is being referenced? The reference function shows a different file name than what you uploaded; there's a difference in underscores vs. spaces in the file name, but only for the Barrier Capacity file. The other 3 files get their relative references correct; that 4th file is also not set for relative reference at all.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers

RE: MATHCAD 15.0 Units problem

(OP)
I'm sure the reference was established correctly. since some of the variables such as nlegse.prov,A.vfreq,V.res were able to be output in my main sheet.
It is just some variables and results that I actually need to use can not be carried over into my main sheet.

RE: MATHCAD 15.0 Units problem

OK, Seems to be a bunch of different problems
> you switched ORIGIN to 1 in the reference sheet, but ORIGIN=0 in the main sheet
> your Long.Data matrix is not transferring, but hardcoding the matrix does allow it to be transferred, but ORIGIN discrepancy still needs to be fixed

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers

RE: MATHCAD 15.0 Units problem

(OP)
Thank you IR.
I was sidetracked by some review tasks. I will get back to my spreadsheet again soon. I will let you know.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close